U.S. patent application number 17/649974 was filed with the patent office on 2022-05-19 for communication system, base station and communication terminal.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Mitsubishi Electric Corporation. Invention is credited to Noriyuki FUKUI, Masaaki KUSANO, Mitsuru MOCHIZUKI, Tadahiro SHIMODA.
Application Number | 20220159704 17/649974 |
Document ID | / |
Family ID | 1000006125473 |
Filed Date | 2022-05-19 |
United States Patent
Application |
20220159704 |
Kind Code |
A1 |
MOCHIZUKI; Mitsuru ; et
al. |
May 19, 2022 |
COMMUNICATION SYSTEM, BASE STATION AND COMMUNICATION TERMINAL
Abstract
Provided is a communication system capable of suppressing
increase in the power consumption of a communication terminal
device, degradation in the communication quality, and reduction in
the use efficiency of radio resources. A base station device (gNB)
notifies a communication terminal device (UE) of information on the
next reception timing. The UE receives, for example, a downlink
control signal in a subframe. The UE obtains, from the downlink
control signal, information on a piece of user data in the
subframe, and the information on the next reception timing. The UE
transmits and receives the piece of user data to and from the gNB.
The information on the next reception timing indicates a subframe
as the next reception timing of the UE. The UE receives a downlink
control signal in the subframe.
Inventors: |
MOCHIZUKI; Mitsuru; (Tokyo,
JP) ; SHIMODA; Tadahiro; (Tokyo, JP) ; FUKUI;
Noriyuki; (Tokyo, JP) ; KUSANO; Masaaki;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitsubishi Electric Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Tokyo
JP
|
Family ID: |
1000006125473 |
Appl. No.: |
17/649974 |
Filed: |
February 4, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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16340228 |
Apr 8, 2019 |
|
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PCT/JP2017/046054 |
Dec 22, 2017 |
|
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17649974 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 52/0209 20130101;
H04W 72/1289 20130101; H04W 16/28 20130101; H04W 84/042
20130101 |
International
Class: |
H04W 72/12 20060101
H04W072/12; H04W 16/28 20060101 H04W016/28 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 22, 2016 |
JP |
2016-249443 |
Claims
1. A communication system comprising a base station and a
communication terminal which can perform radio communication with
the base station, wherein the base station transmits a physical
downlink control channel reception period and an offset, and the
communication terminal receives the physical downlink control
channel reception period and the offset.
2. A base station in a communication system comprising a base
station and a communication terminal which can perform radio
communication with the base station, wherein the base station
transmits a physical downlink control channel reception period and
an offset.
3. A communication terminal in a communication system comprising a
base station and a communication terminal which can perform radio
communication with the base station, wherein the communication
terminal receives a physical downlink control channel reception
period and an offset.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of and claims the benefit
of U.S. application Ser. No. 16/340,228, filed on Apr. 8, 2019,
which is a National Stage Application of PCT/JP2017/046054, filed
on Dec. 22, 2017, which claims the benefit of Japanese Patent
Application No. 2016-249443, filed on Dec. 22, 2016.
TECHNICAL FIELD
[0002] The present invention relates to a communication system in
which radio communication is performed between a communication
terminal device such as a user equipment device and a base station
device.
BACKGROUND ART
[0003] The 3rd generation partnership project (3GPP), the standard
organization regarding the mobile communication system, is studying
communication systems referred to as long term evolution (LTE)
regarding radio sections and system architecture evolution (SAE)
regarding the overall system configuration including a core network
and a radio access network, which will be hereinafter collectively
referred to as a network as well (for example, see Non-Patent
Documents 1 to 5). This communication system is also referred to as
3.9 generation (3.9 G) system.
[0004] As the access scheme of the LTE, orthogonal frequency
division multiplexing (OFDM) is used in a downlink direction and
single carrier frequency division multiple access (SC-FDMA) is used
in an uplink direction. Further, differently from the wideband code
division multiple access (W-CDMA), circuit switching is not
provided but a packet communication system is only provided in the
LTE.
[0005] The decisions by 3GPP regarding the frame configuration in
the LTE system described in Non-Patent Document 1 (Chapter 5) will
be described with reference to FIG. 1. FIG. 1 is a diagram
illustrating the configuration of a radio frame used in the LTE
communication system. With reference to FIG. 1, one radio frame is
10 ms. The radio frame is divided into ten equally sized subframes.
The subframe is divided into two equally sized slots. The first and
sixth subframes contain a downlink synchronization signal per radio
frame. The synchronization signals are classified into a primary
synchronization signal (P-SS) and a secondary synchronization
signal (S-SS).
[0006] Non-Patent Document 1 (Chapter 5) describes the decisions by
3GPP regarding the channel configuration in the LTE system. It is
assumed that the same channel configuration is used in a closed
subscriber group (CSG) cell as that of a non-CSG cell.
[0007] A physical broadcast channel (PBCH) is a channel for
downlink transmission from a base station device (hereinafter may
be simply referred to as a "base station") to a communication
terminal device (hereinafter may be simply referred to as a
"communication terminal") such as a user equipment device
(hereinafter may be simply referred to as a "user equipment"). A
BCH transport block is mapped to four subframes within a 40 ms
interval. There is no explicit signaling indicating 40 ms
timing.
[0008] A physical control format indicator channel (PCFICH) is a
channel for downlink transmission from a base station to a
communication terminal. The PCFICH notifies the number of
orthogonal frequency division multiplexing (OFDM) symbols used for
PDCCHs from the base station to the communication terminal. The
PCFICH is transmitted per subframe.
[0009] A physical downlink control channel (PDCCH) is a channel for
downlink transmission from a base station to a communication
terminal. The PDCCH notifies of the resource allocation information
for downlink shared channel (DL-SCH) being one of the transport
channels described below, resource allocation information for a
paging channel (PCH) being one of the transport channels described
below, and hybrid automatic repeat request (HARM) information
related to DL-SCH. The PDCCH carries an uplink scheduling grant.
The PDCCH carries acknowledgement (Ack)/negative acknowledgement
(Nack) that is a response signal to uplink transmission. The PDCCH
is referred to as an L1/L2 control signal as well.
[0010] A physical downlink shared channel (PDSCH) is a channel for
downlink transmission from a base station to a communication
terminal. A downlink shared channel (DL-SCH) that is a transport
channel and a PCH that is a transport channel are mapped to the
PDSCH.
[0011] A physical multicast channel (PMCH) is a channel for
downlink transmission from a base station to a communication
terminal. A multicast channel (MCH) that is a transport channel is
mapped to the PMCH.
[0012] A physical uplink control channel (PUCCH) is a channel for
uplink transmission from a communication terminal to a base
station. The PUCCH carries Ack/Nack that is a response signal to
downlink transmission. The PUCCH carries a channel quality
indicator (CQI) report. The CQI is quality information indicating
the quality of received data or channel quality. In addition, the
PUCCH carries a scheduling request (SR).
[0013] A physical uplink shared channel (PUSCH) is a channel for
uplink transmission from a communication terminal to a base
station. An uplink shared channel (UL-SCH) that is one of the
transport channels is mapped to the PUSCH.
[0014] A physical hybrid ARQ indicator channel (PHICH) is a channel
for downlink transmission from a base station to a communication
terminal. The PHICH carries Ack/Nack that is a response signal to
uplink transmission. A physical random access channel (PRACH) is a
channel for uplink transmission from the communication terminal to
the base station. The PRACH carries a random access preamble.
[0015] A downlink reference signal (RS) is a known symbol in the
LTE communication system. The following five types of downlink
reference signals are defined: a cell-specific reference signal
(CRS), an MBSFN reference signal, a data demodulation reference
signal (DM-RS) being a UE-specific reference signal, a positioning
reference signal (PRS), and a channel state information reference
signal (CSI-RS). The physical layer measurement objects of a
communication terminal include reference signal received power
(RSRP).
[0016] The transport channels described in Non-Patent Document 1
(Chapter 5) will be described. A broadcast channel (BCH) among the
downlink transport channels is broadcast to the entire coverage of
a base station (cell). The BCH is mapped to the physical broadcast
channel (PBCH).
[0017] Retransmission control according to a hybrid ARQ (HARM) is
applied to a downlink shared channel (DL-SCH). The DL-SCH can be
broadcast to the entire coverage of the base station (cell). The
DL-SCH supports dynamic or semi-static resource allocation. The
semi-static resource allocation is also referred to as persistent
scheduling. The DL-SCH supports discontinuous reception (DRX) of a
communication terminal for enabling the communication terminal to
save power. The DL-SCH is mapped to the physical downlink shared
channel (PDSCH).
[0018] The paging channel (PCH) supports DRX of the communication
terminal for enabling the communication terminal to save power. The
PCH is required to be broadcast to the entire coverage of the base
station (cell). The PCH is mapped to physical resources such as the
physical downlink shared channel (PDSCH) that can be used
dynamically for traffic.
[0019] The multicast channel (MCH) is used for broadcast to the
entire coverage of the base station (cell). The MCH supports SFN
combining of multimedia broadcast multicast service (MBMS) services
(MTCH and MCCH) in multi-cell transmission. The MCH supports
semi-static resource allocation. The MCH is mapped to the PMCH.
[0020] Retransmission control according to a hybrid ARQ (HARQ) is
applied to an uplink shared channel (UL-SCH) among the uplink
transport channels. The UL-SCH supports dynamic or semi-static
resource allocation. The UL-SCH is mapped to the physical uplink
shared channel (PUSCH).
[0021] A random access channel (RACH) is limited to control
information. The RACH involves a collision risk. The RACH is mapped
to the physical random access channel (PRACH).
[0022] The HARQ will be described. The HARQ is the technique for
improving the communication quality of a channel by combination of
automatic repeat request (ARQ) and error correction (forward error
correction). The HARQ is advantageous in that error correction
functions effectively by retransmission even for a channel whose
communication quality changes. In particular, it is also possible
to achieve further quality improvement in retransmission through
combination of the reception results of the first transmission and
the reception results of the retransmission.
[0023] An example of the retransmission method will be described.
If the receiver fails to successfully decode the received data, in
other words, if a cyclic redundancy check (CRC) error occurs
(CRC=NG), the receiver transmits "Nack" to the transmitter. The
transmitter that has received "Nack" retransmits the data. If the
receiver successfully decodes the received data, in other words, if
a CRC error does not occur (CRC=OK), the receiver transmits "AcK"
to the transmitter. The transmitter that has received "Ack"
transmits the next data.
[0024] The logical channels described in Non-Patent Document 1
(Chapter 6) will be described. A broadcast control channel (BCCH)
is a downlink channel for broadcast system control information. The
BCCH that is a logical channel is mapped to the broadcast channel
(BCH) or downlink shared channel (DL-SCH) that is a transport
channel.
[0025] A paging control channel (PCCH) is a downlink channel for
transmitting paging information and system information change
notifications. The PCCH is used when the network does not know the
cell location of a communication terminal. The PCCH that is a
logical channel is mapped to the paging channel (PCH) that is a
transport channel.
[0026] A common control channel (CCCH) is a channel for
transmission control information between communication terminals
and a base station. The CCCH is used in the case where the
communication terminals have no RRC connection with the network. In
the downlink direction, the CCCH is mapped to the downlink shared
channel (DL-SCH) that is a transport channel. In the uplink
direction, the CCCH is mapped to the uplink shared channel (UL-SCH)
that is a transport channel.
[0027] A multicast control channel (MCCH) is a downlink channel for
point-to-multipoint transmission. The MCCH is used for transmission
of MBMS control information for one or several MTCHs from a network
to a communication terminal. The MCCH is used only by a
communication terminal during reception of the MBMS. The MCCH is
mapped to the multicast channel (MCH) that is a transport
channel.
[0028] A dedicated control channel (DCCH) is a channel that
transmits dedicated control information between a communication
terminal and a network on a point-to-point basis. The DCCH is used
when the communication terminal has an RRC connection. The DCCH is
mapped to the uplink shared channel (UL-SCH) in uplink and mapped
to the downlink shared channel (DL-SCH) in downlink.
[0029] A dedicated traffic channel (DTCH) is a point-to-point
communication channel for transmission of user information to a
dedicated communication terminal. The DTCH exists in uplink as well
as downlink. The DTCH is mapped to the uplink shared channel
(UL-SCH) in uplink and mapped to the downlink shared channel
(DL-SCH) in downlink.
[0030] A multicast traffic channel (MTCH) is a downlink channel for
traffic data transmission from a network to a communication
terminal. The MTCH is a channel used only by a communication
terminal during reception of the MBMS. The MTCH is mapped to the
multicast channel (MCH).
[0031] CGI represents a cell global identifier. ECGI represents an
E-UTRAN cell global identifier. A closed subscriber group (CSG)
cell is introduced in the LTE, and the long term evolution advanced
(LTE-A) and universal mobile telecommunication system (UMTS)
described below.
[0032] The closed subscriber group (CSG) cell is a cell in which
subscribers who are allowed use are specified by an operator
(hereinafter, also referred to as a "cell for specific
subscribers"). The specified subscribers are allowed to access one
or more cells of a public land mobile network (PLMN). One or more
cells to which the specified subscribers are allowed access are
referred to as "CSG cell(s)". Note that access is limited in the
PLMN.
[0033] The CSG cell is part of the PLMN that broadcasts a specific
CSG identity (CSG ID) and broadcasts "TRUE" in a CSG indication.
The authorized members of the subscriber group who have registered
in advance access the CSG cells using the CSG ID that is the access
permission information.
[0034] The CSG ID is broadcast by the CSG cell or cells. A
plurality of CSG IDs exist in the LTE communication system. The CSG
IDs are used by communication terminals (UEs) for making access
from CSG-related members easier.
[0035] The locations of communication terminals are tracked based
on an area composed of one or more cells. The locations are tracked
for enabling tracking the locations of communication terminals and
calling communication terminals, in other words, incoming calling
to communication terminals even in an idle state. An area for
tracking locations of communication terminals is referred to as a
tracking area.
[0036] 3GPP is studying base stations referred to as Home-NodeB
(Home-NB; HNB) and Home-eNodeB (Home-eNB; HeNB). HNB/HeNB is a base
station for, for example, household, corporation, or commercial
access service in UTRAN/E-UTRAN. Non-Patent Document 2 discloses
three different modes of the access to the HeNB and HNB.
Specifically, an open access mode, a closed access mode, and a
hybrid access mode are disclosed.
[0037] Further, 3GPP is pursuing specifications standard of long
term evolution advanced (LTE-A) as Release 10 (see Non-Patent
Documents 3 and 4). The LTE-A is based on the LTE radio
communication system and is configured by adding several new
techniques to the system.
[0038] Carrier aggregation (CA) is studied for the LTE-A system, in
which two or more component carriers (CCs) are aggregated to
support wider transmission bandwidths up to 100 MHz. Non-Patent
Document 1 describes the CA.
[0039] In the case where CA is configured, a UE has a single RRC
connection with a network (NW). In RRC connection, one serving cell
provides NAS mobility information and security input. This cell is
referred to as a primary cell (PCell). In downlink, a carrier
corresponding to PCell is a downlink primary component carrier (DL
PCC). In uplink, a carrier corresponding to PCell is an uplink
primary component carrier (UL PCC).
[0040] A secondary cell (SCell) is configured to form a serving
cell group with a PCell, in accordance with the UE capability. In
downlink, a carrier corresponding to SCell is a downlink secondary
component carrier (DL SCC). In uplink, a carrier corresponding to
SCell is an uplink secondary component carrier (UL SCC).
[0041] A serving cell group of one PCell and one or more SCells is
configured for one UE.
[0042] The new techniques in the LTE-A include the technique of
supporting wider bands (wider bandwidth extension) and the
coordinated multiple point transmission and reception (CoMP)
technique. The CoMP studied for LTE-A in 3GPP is described in
Non-Patent Document 1.
[0043] Furthermore, 3GPP is studying the use of small eNB s
(hereinafter also referred to as "small-scale base station
devices") configuring small cells to satisfy tremendous traffic in
the future. In an example technique under study, etc., a large
number of small eNBs will be installed to configure a large number
of small cells, thus increasing spectral efficiency and
communication capacity. The specific techniques include dual
connectivity (abbreviated as DC) in which a UE communicates with
two eNBs through connection thereto. Non-Patent Document 1
describes the DC.
[0044] Among eNBs that perform dual connectivity (DC), one of them
may be referred to as a master eNB (abbreviated as MeNB), and the
other may be referred to as a secondary eNB (abbreviated as
SeNB).
[0045] The traffic flow of a mobile network is on the rise, and the
communication rate is also increasing. It is expected that the
communication rate will be further increased when the operations of
the LTE and the LTE-A are fully initiated.
[0046] For increasingly sophisticated mobile communications, the
fifth generation (hereinafter also referred to as "5G") radio
access system is studied, whose service is aimed to be launched in
2020 and afterward. For example, in the Europe, an organization
named METIS summarizes the requirements for 5G (see Non-Patent
Document 5).
[0047] Among the requirements in the 5G radio access system are a
system capacity 1000 times as high as, a data transmission rate 100
times as high as, a data latency one tenth ( 1/10) as low as, and
simultaneously connected communication terminals 100 times as many
as those in the LTE system, to further reduce the power consumption
and device cost.
[0048] To satisfy such requirements, 3GPP is pursuing the study of
5G standards as Release 14 (see Non-Patent Documents 6 to 10). The
techniques on 5G radio sections are referred to as "New Radio
(abbreviated as NR) Access Technology", and the several new
techniques are being studied (see Non-Patent Documents 11 to 13).
Examples of the techniques include a NR frame structure using a
self-contained subframe, multi-beamforming (MBF) through analog
beamforming or hybrid beamforming, beam sweeping in the MBF, and
the maximum code block size in coding.
PRIOR-ART DOCUMENTS
Non-Patent Documents
[0049] Non-Patent Document 1: 3GPP TS36.300 V14.0.0 [0050]
Non-Patent Document 2: 3GPP S1-083461 [0051] Non-Patent Document 3:
3GPP TR 36.814 V9.0.0 [0052] Non-Patent Document 4: 3GPP TR 36.912
V13.0.0 [0053] Non-Patent Document 5: "Scenarios, requirements and
KPIs for 5G mobile and wireless system", [online], Apr. 30, 2013,
ICT-317669-METIS/D1.1, [Searched on Dec. 13, 2016], Internet
<https://www.metis2020.com/documents/deliverables/> [0054]
Non-Patent Document 6: 3GPP TR 23.799 V1.1.0 [0055] Non-Patent
Document 7: 3GPP TR 38.801 V0.4.0 [0056] Non-Patent Document 8:
3GPP TR 38.802 V0.3.0 [0057] Non-Patent Document 9: 3GPP TR 38.804
V0.3.0 [0058] Non-Patent Document 10: 3GPP TR 38.912 V0.0.2 [0059]
Non-Patent Document 11: 3GPP R1-166104 [0060] Non-Patent Document
12: 3GPP R1-165364 [0061] Non-Patent Document 13: 3GPP
R1-1609068
SUMMARY
Problems to be Solved by the Invention
[0062] The multi-beamforming is being studied in the NR. In the
multi-beamforming, the beam sweeping is performed with different
timings using one or more beams to cover a necessary coverage when
the number of beams formed by the cell at a time is less. Thus,
each of the beams formed by the cell cannot be transmitted or
received with all the timings.
[0063] In the LTE, the UE needs to receive a downlink control
channel in each subframe, since the dynamic scheduling is normally
performed. Since the beams cannot be transmitted or received with
all the timings during the beam sweeping in the multi-beamforming
as previously described, it is useless for the UE to continue to
receive the downlink control channel in each subframe. Thus,
unnecessary power consumption will be increased. Moreover, it is
useless for the UE to transmit an uplink control channel with the
timings of the beams that cannot be transmitted or received. The
power consumption will be increased, and the uplink communication
becomes impossible.
[0064] In the multi-beamforming, one cell forms a plurality of
beams, and forms a coverage for each of the beams. Thus, the
coverage of the beam is narrower than the coverage of the cell.
Unless the coverage of the beam is appropriately formed, problems
occur e.g., a coverage hole, and being susceptible to disconnection
in communication during the movement of the UE between beams.
[0065] It is expected in the NR that the broadening of use
frequency band increases the size of a transport block and also the
number of code blocks. Since the Ack/Nack feedback scheme such as
the LTE involves retransmission of the whole transport block
including code blocks that have successfully been received,
increase in the number of code blocks will cause substantial
reduction in the use efficiency of radio resources.
[0066] Thus, retransmitting a code block that cannot be accurately
decoded according to the HARQ is being studied in the NR. However,
when a plurality of code blocks have reception errors due to being
high in number, a problem of increase in the number of bits
required for the feedback occurs. This will cause increase in the
power consumption of the UE and reduction in the use efficiency of
the radio resources.
[0067] The object of the present invention is to provide a
communication system that can suppress increase in the power
consumption of a communication terminal device, degradation in the
communication quality, and reduction in the use efficiency of the
radio resources.
Means to Solve the Problems
[0068] A communication system according to the present invention
includes a base station device and at least one communication
terminal device capable of radio communication with the base
station device, wherein the base station device notifies the
communication terminal device of information on a next reception
timing, and the communication terminal device performs reception
based on the information on the next reception timing that has been
notified from the base station device.
Effects of the Invention
[0069] A communication system according to the present invention
includes a base station device and at least one communication
terminal device capable of radio communication with the base
station device. The base station device notifies the communication
terminal device of information on a next reception timing. The
communication terminal device performs reception based on the
information on the next reception timing that has been notified
from the base station device. Since the communication terminal
device can receive the information transmitted from the base
station device with the notified reception timing, the power
consumption required for the reception can be saved. Since
retransmission can be promptly performed when the retransmission is
necessary, the latency in the communication between the base
station device and the communication terminal device can be
reduced. Thus, increase in the power consumption of the
communication terminal device, degradation in the communication
quality, and reduction in the use efficiency of radio resources can
be suppressed.
[0070] These and other objects, features, aspects and advantages of
the present invention will become more apparent from the following
detailed description of the present invention when taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0071] FIG. 1 is a diagram illustrating the configuration of a
radio frame for use in an LTE communication system.
[0072] FIG. 2 is a block diagram showing the overall configuration
of an LTE communication system 200 under discussion of 3GPP.
[0073] FIG. 3 is a block diagram showing the configuration of a
user equipment 202 shown in FIG. 2, which is a communication
terminal according to the present invention.
[0074] FIG. 4 is a block diagram showing the configuration of a
base station 203 shown in FIG. 2, which is a base station according
to the present invention.
[0075] FIG. 5 is a block diagram showing the configuration of an
MME according to the present invention.
[0076] FIG. 6 is a flowchart showing an outline from a cell search
to an idle state operation performed by a communication terminal
(UE) in the LTE communication system.
[0077] FIG. 7 shows the concept of a cell configuration when macro
eNBs and small eNBs coexist.
[0078] FIG. 8 illustrates the beam sweeping.
[0079] FIG. 9 illustrates one example where the gNB notifies the UE
of the next timing with which the PDCCH needs to be received and
the UE transmits and receives the uplink/downlink data.
[0080] FIG. 10 illustrates one example where the gNB notifies the
UE of the PDCCH reception timing for a predefined duration and the
UE transmits and receives the uplink/downlink data.
[0081] FIG. 11 illustrates transmission/reception channels in the
uplink communication when the notification of Ack/Nack and the
retransmission are performed in a subframe next to the uplink
initial transmission.
[0082] FIG. 12 illustrates one example method for setting the PUCCH
resources for each beam using a period, an offset, and a symbol
number.
[0083] FIG. 13 illustrates one example method for setting the
PUCCHs as many as the number of times the beam sweeping is
performed within k subframes.
[0084] FIG. 14 illustrates another example method for setting the
PUCCHs as many as the number of times the beam sweeping is
performed within k subframes.
[0085] FIG. 15 illustrates yet another example method for setting
the PUCCHs as many as the number of times the beam sweeping is
performed within k subframes.
[0086] FIG. 16 illustrates one example sequence for setting the
PUCCHs and transmitting and receiving the SR.
[0087] FIG. 17 illustrates one example sequence for setting the
PUCCHs for each UE and transmitting and receiving the SR.
[0088] FIG. 18 illustrates one example method for setting
information on starting, modifying, and stopping the setting of the
PUCCH resources to each UE.
[0089] FIG. 19 illustrates one example sequence for setting the
PUCCHs for each UE and transmitting and receiving the SR.
[0090] FIG. 20 illustrates one example method for setting the PUCCH
resources in a subframe identical to that for the DL resources for
the serving beam of the UE.
[0091] FIG. 21 illustrates one example sequence for setting the
PUCCH resources in the subframe identical to that for the DL
resources and transmitting and receiving the SR.
[0092] FIG. 22 illustrates one example sequence for transmitting
and receiving the SR when priorities for receiving the PUCCH are
assigned to beams.
[0093] FIG. 23 illustrates the one example sequence for
transmitting and receiving the SR when priorities for receiving the
PUCCH are assigned to beams.
[0094] FIG. 24 illustrates one example sequence for setting the
transmission/reception timing of the uplink grant for the SR.
[0095] FIG. 25 illustrates one example sequence for setting the
transmission/reception timing of the uplink grant for the SR upon
movement between beams after transmission of the SR.
[0096] FIG. 26 illustrates the one example sequence for setting the
transmission/reception timing of the uplink grant for the SR upon
movement between beams after transmission of the SR.
[0097] FIG. 27 illustrates another example sequence for setting the
transmission/reception timing of the uplink grant for the SR upon
movement between beams after transmission of the SR.
[0098] FIG. 28 illustrates the other example sequence for setting
the transmission/reception timing of the uplink grant for the SR
upon movement between beams after transmission of the SR.
[0099] FIG. 29 illustrates reception errors in code blocks due to
the URLLC interrupt.
[0100] FIG. 30 illustrates associations between code blocks and a
plurality of CBGs when the code blocks belong to the plurality of
CBGs.
[0101] FIG. 31 illustrates a relationship between a code block
cluster and consecutive code blocks including reception errors.
[0102] FIG. 32 illustrates patterns of code blocks including
reception errors.
[0103] FIG. 33 illustrates the assignment of parity checks 3401 to
3404 to the respective CBGs.
DESCRIPTION OF EMBODIMENTS
First Embodiment
[0104] FIG. 2 is a block diagram showing an overall configuration
of an LTE communication system 200, which is under discussion of
3GPP. FIG. 2 will be described. A radio access network is referred
to as an evolved universal terrestrial radio access network
(E-UTRAN) 201. A user equipment device (hereinafter, referred to as
a "user equipment (UE)") 202 that is a communication terminal
device is capable of radio communication with a base station device
(hereinafter, referred to as a "base station (E-UTRAN Node B:
eNB)") 203 and transmits and receives signals through radio
communication.
[0105] Here, the "communication terminal device" covers not only a
user equipment device such as a movable mobile phone terminal
device, but also an unmovable device such as a sensor. In the
following description, the "communication terminal device" may be
simply referred to as a "communication terminal".
[0106] The E-UTRAN is composed of one or a plurality of base
stations 203, provided that a control protocol for the user
equipment 202 such as a radio resource control (RRC), and user
planes such as a packet data convergence protocol (PDCP), radio
link control (RLC), medium access control (MAC), or physical layer
(PHY) are terminated in the base station 203.
[0107] The control protocol radio resource control (RRC) between
the user equipment 202 and the base station 203 performs broadcast,
paging, RRC connection management, and the like. The states of the
base station 203 and the user equipment 202 in RRC are classified
into RRC_IDLE and RRC_CONNECTED.
[0108] In RRC_IDLE, public land mobile network (PLMN) selection,
system information (SI) broadcast, paging, cell re-selection,
mobility, and the like are performed. In RRC_CONNECTED, the user
equipment has RRC connection and is capable of transmitting and
receiving data to and from a network. In RRC_CONNECTED, for
example, handover (HO) and measurement of a neighbor cell are
performed.
[0109] The base stations 203 are classified into eNBs 207 and
Home-eNBs 206. The communication system 200 includes an eNB group
203-1 including a plurality of eNBs 207 and a Home-eNB group 203-2
including a plurality of Home-eNBs 206. A system, composed of an
evolved packet core (EPC) being a core network and an E-UTRAN 201
being a radio access network, is referred to as an evolved packet
system (EPS). The EPC being a core network and the E-UTRAN 201
being a radio access network may be collectively referred to as a
"network".
[0110] The eNB 207 is connected to an MME/S-GW unit (hereinafter,
also referred to as an "MME unit") 204 including a mobility
management entity (MME), a serving gateway (S-GW), or an MME and an
S-GW by means of an S1 interface, and control information is
communicated between the eNB 207 and the MME unit 204. A plurality
of MME units 204 may be connected to one eNB 207. The eNBs 207 are
connected to each other by means of an X2 interface, and control
information is communicated between the eNB s 207.
[0111] The Home-eNB 206 is connected to the MME unit 204 by means
of an S1 interface, and control information is communicated between
the Home-eNB 206 and the MME unit 204. A plurality of Home-eNBs 206
are connected to one MME unit 204. Or, the Home-eNBs 206 are
connected to the MME units 204 through a Home-eNB gateway (HeNBGW)
205. The Home-eNB 206 is connected to the HeNBGW 205 by means of an
S1 interface, and the HeNBGW 205 is connected to the MME unit 204
by means of an S1 interface.
[0112] One or a plurality of Home-eNBs 206 are connected to one
HeNBGW 205, and information is communicated therebetween through an
S1 interface. The HeNBGW 205 is connected to one or a plurality of
MME units 204, and information is communicated therebetween through
an S1 interface.
[0113] The MME units 204 and HeNBGW 205 are entities of higher
layer, specifically, higher nodes, and control the connections
between the user equipment (UE) 202 and the eNB 207 and the
Home-eNB 206 being base stations. The MME units 204 configure an
EPC being a core network. The base station 203 and the HeNBGW 205
configure the E-UTRAN 201.
[0114] Further, 3GPP is studying the configuration below. The X2
interface between the Home-eNBs 206 is supported. In other words,
the Home-eNBs 206 are connected to each other by means of an X2
interface, and control information is communicated between the
Home-eNBs 206. The HeNBGW 205 appears to the MME unit 204 as the
Home-eNB 206. The HeNBGW 205 appears to the Home-eNB 206 as the MME
unit 204.
[0115] The interfaces between the Home-eNBs 206 and the MME units
204 are the same, which are the S1 interfaces, in both cases where
the Home-eNB 206 is connected to the MME unit 204 through the
HeNBGW 205 and it is directly connected to the MME unit 204.
[0116] The base station device 203 may configure a single cell or a
plurality of cells. Each cell has a range predetermined as a
coverage in which the cell can communicate with the user equipment
202 and performs radio communication with the user equipment 202
within the coverage. In the case where one base station device 203
configures a plurality of cells, every cell is configured so as to
communicate with the user equipment 202.
[0117] FIG. 3 is a block diagram showing the configuration of the
user equipment 202 of FIG. 2 that is a communication terminal
according to the present invention. The transmission process of the
user equipment 202 shown in FIG. 3 will be described. First, a
transmission data buffer unit 303 stores the control data from a
protocol processing unit 301 and the user data from an application
unit 302. The data stored in the transmission data buffer unit 303
is passed to an encoding unit 304 and is subjected to an encoding
process such as error correction. There may exist the data output
from the transmission data buffer unit 303 directly to a modulating
unit 305 without the encoding process. The data encoded by the
encoding unit 304 is modulated by the modulating unit 305. The
modulated data is converted into a baseband signal, and the
baseband signal is output to a frequency converting unit 306 and is
then converted into a radio transmission frequency. After that, a
transmission signal is transmitted from an antenna 307 to the base
station 203.
[0118] The user equipment 202 executes the reception process as
follows. The radio signal from the base station 203 is received
through the antenna 307. The received signal is converted from a
radio reception frequency into a baseband signal by the frequency
converting unit 306 and is then demodulated by a demodulating unit
308. The demodulated data is passed to a decoding unit 309 and is
subjected to a decoding process such as error correction. Among the
pieces of decoded data, the control data is passed to the protocol
processing unit 301, and the user data is passed to the application
unit 302. A series of processes by the user equipment 202 is
controlled by a control unit 310. This means that, though not shown
in FIG. 3, the control unit 310 is connected to the individual
units 301 to 309.
[0119] FIG. 4 is a block diagram showing the configuration of the
base station 203 of FIG. 2 that is a base station according to the
present invention. The transmission process of the base station 203
shown in FIG. 4 will be described. An EPC communication unit 401
performs data transmission and reception between the base station
203 and the EPC (such as the MME unit 204), HeNBGW 205, and the
like. A communication with another base station unit 402 performs
data transmission and reception to and from another base station.
The EPC communication unit 401 and the communication with another
base station unit 402 each transmit and receive information to and
from a protocol processing unit 403. The control data from the
protocol processing unit 403, and the user data and the control
data from the EPC communication unit 401 and the communication with
another base station unit 402 are stored in a transmission data
buffer unit 404.
[0120] The data stored in the transmission data buffer unit 404 is
passed to an encoding unit 405 and is then subjected to an encoding
process such as error correction. There may exist the data output
from the transmission data buffer unit 404 directly to a modulating
unit 406 without the encoding process. The encoded data is
modulated by the modulating unit 406. The modulated data is
converted into a baseband signal, and the baseband signal is output
to a frequency converting unit 407 and is then converted into a
radio transmission frequency. After that, a transmission signal is
transmitted from an antenna 408 to one or a plurality of user
equipments 202.
[0121] The reception process of the base station 203 is executed as
follows. A radio signal from one or a plurality of user equipments
202 is received through the antenna 408. The received signal is
converted from a radio reception frequency into a baseband signal
by the frequency converting unit 407, and is then demodulated by a
demodulating unit 409. The demodulated data is passed to a decoding
unit 410 and is then subjected to a decoding process such as error
correction. Among the pieces of decoded data, the control data is
passed to the protocol processing unit 403, the EPC communication
unit 401, or the communication with another base station unit 402,
and the user data is passed to the EPC communication unit 401 and
the communication with another base station unit 402. A series of
processes by the base station 203 is controlled by a control unit
411. This means that, though not shown in FIG. 4, the control unit
411 is connected to the individual units 401 to 410.
[0122] FIG. 5 is a block diagram showing the configuration of the
MME according to the present invention. FIG. 5 shows the
configuration of an MME 204a included in the MME unit 204 shown in
FIG. 2 described above. A PDN GW communication unit 501 performs
data transmission and reception between the MME 204a and the PDN
GW. A base station communication unit 502 performs data
transmission and reception between the MME 204a and the base
station 203 by means of the S1 interface. In the case where the
data received from the PDN GW is user data, the user data is passed
from the PDN GW communication unit 501 to the base station
communication unit 502 via a user plane communication unit 503 and
is then transmitted to one or a plurality of base stations 203. In
the case where the data received from the base station 203 is user
data, the user data is passed from the base station communication
unit 502 to the PDN GW communication unit 501 via the user plane
communication unit 503 and is then transmitted to the PDN GW.
[0123] In the case where the data received from the PDN GW is
control data, the control data is passed from the PDN GW
communication unit 501 to a control plane control unit 505. In the
case where the data received from the base station 203 is control
data, the control data is passed from the base station
communication unit 502 to the control plane control unit 505.
[0124] A HeNBGW communication unit 504 is provided in the case
where the HeNBGW 205 is provided, which performs data transmission
and reception between the MME 204a and the HeNBGW 205 by means of
the interface (IF) according to an information type. The control
data received from the HeNBGW communication unit 504 is passed from
the HeNBGW communication unit 504 to the control plane control unit
505. The processing results of the control plane control unit 505
are transmitted to the PDN GW via the PDN GW communication unit
501. The processing results of the control plane control unit 505
are transmitted to one or a plurality of base stations 203 by means
of the S1 interface via the base station communication unit 502,
and are transmitted to one or a plurality of HeNBGWs 205 via the
HeNBGW communication unit 504.
[0125] The control plane control unit 505 includes a NAS security
unit 505-1, an SAE bearer control unit 505-2, and an idle state
mobility managing unit 505-3, and performs an overall process for
the control plane. The NAS security unit 505-1 provides, for
example, security of a non-access stratum (NAS) message. The SAE
bearer control unit 505-2 manages, for example, a system
architecture evolution (SAE) bearer. The idle state mobility
managing unit 505-3 performs, for example, mobility management of
an idle state (LTE-IDLE state, which is merely referred to as idle
as well), generation and control of a paging signal in the idle
state, addition, deletion, update, and search of a tracking area of
one or a plurality of user equipments 202 being served thereby, and
tracking area list management.
[0126] The MME 204a distributes a paging signal to one or a
plurality of base stations 203. In addition, the MME 204a performs
mobility control of an idle state. When the user equipment is in
the idle state and an active state, the MME 204a manages a list of
tracking areas. The MME 204a begins a paging protocol by
transmitting a paging message to the cell belonging to a tracking
area in which the UE is registered. The idle state mobility
managing unit 505-3 may manage the CSG of the Home-eNBs 206 to be
connected to the MME 204a, CSG IDs, and a whitelist.
[0127] An example of a cell search method in a mobile communication
system will be described next. FIG. 6 is a flowchart showing an
outline from a cell search to an idle state operation performed by
a communication terminal (UE) in the LTE communication system. When
starting a cell search, in Step ST601, the communication terminal
synchronizes slot timing and frame timing by a primary
synchronization signal (P-SS) and a secondary synchronization
signal (S-SS) transmitted from a neighbor base station.
[0128] The P-SS and S-SS are collectively referred to as a
synchronization signal (SS). Synchronization codes, which
correspond one-to-one to PCIs assigned per cell, are assigned to
the synchronization signals (SSs). The number of PCIs is currently
studied in 504 ways. The 504 ways of PCIs are used for
synchronization, and the PCIs of the synchronized cells are
detected (specified).
[0129] In Step ST602, next, the user equipment detects a
cell-specific reference signal (CRS) being a reference signal (RS)
transmitted from the base station per cell and measures the
reference signal received power (RSRP). The codes corresponding
one-to-one to the PCIs are used for the reference signal RS.
Separation from another cell is enabled by correlation using the
code. The code for RS of the cell is derived from the PCI specified
in Step ST601, so that the RS can be detected and the RS received
power can be measured.
[0130] In Step ST603, next, the user equipment selects the cell
having the best RS received quality, for example, the cell having
the highest RS received power, that is, the best cell, from one or
more cells that have been detected up to Step ST602.
[0131] In Step ST604, next, the user equipment receives the PBCH of
the best cell and obtains the BCCH that is the broadcast
information. A master information block (MIB) containing the cell
configuration information is mapped to the BCCH over the PBCH.
Accordingly, the MIB is obtained by obtaining the BCCH through
reception of the PBCH. Examples of the MIB information include the
downlink (DL) system bandwidth (also referred to as a transmission
bandwidth configuration (dl-bandwidth)), the number of transmission
antennas, and a system frame number (SFN).
[0132] In Step ST605, next, the user equipment receives the DL-SCH
of the cell based on the cell configuration information of the MIB,
to thereby obtain a system information block (SIB) 1 of the
broadcast information BCCH. The SIB1 contains the information about
the access to the cell, information about cell selection, and
scheduling information on another SIB (SIBk; k is an integer equal
to or greater than two). In addition, the SIB1 contains a tracking
area code (TAC).
[0133] In Step ST606, next, the communication terminal compares the
TAC of the SIB1 received in Step ST605 with the TAC portion of a
tracking area identity (TAI) in the tracking area list that has
already been possessed by the communication terminal. The tracking
area list is also referred to as a TAI list. TAI is the
identification information for identifying tracking areas and is
composed of a mobile country code (MCC), a mobile network code
(MNC), and a tracking area code (TAC). MCC is a country code. MNC
is a network code. TAC is the code number of a tracking area.
[0134] If the result of the comparison of Step ST606 shows that the
TAC received in Step ST605 is identical to the TAC included in the
tracking area list, the user equipment enters an idle state
operation in the cell. If the comparison shows that the TAC
received in Step ST605 is not included in the tracking area list,
the communication terminal requires a core network (EPC) including
MME and the like to change a tracking area through the cell for
performing tracking area update (TAU).
[0135] The device configuring a core network (hereinafter, also
referred to as a "core-network-side device") updates the tracking
area list based on an identification number (such as UE-ID) of a
communication terminal transmitted from the communication terminal
together with a TAU request signal. The core-network-side device
transmits the updated tracking area list to the communication
terminal. The communication terminal rewrites (updates) the TAC
list of the communication terminal based on the received tracking
area list. After that, the communication terminal enters the idle
state operation in the cell.
[0136] Widespread use of smartphones and tablet terminal devices
explosively increases traffic in cellular radio communications,
causing a fear of insufficient radio resources all over the world.
To increase spectral efficiency, thus, it is studied to downsize
cells for further spatial separation.
[0137] In the conventional configuration of cells, the cell
configured by an eNB has a relatively-wide-range coverage.
Conventionally, cells are configured such that
relatively-wide-range coverages of a plurality of cells configured
by a plurality of macro eNBs cover a certain area.
[0138] When cells are downsized, the cell configured by an eNB has
a narrow-range coverage compared with the coverage of a cell
configured by a conventional eNB. Thus, in order to cover a certain
area as in the conventional case, a larger number of downsized eNBs
than the conventional eNBs are required.
[0139] In the description below, a "macro cell" refers to a cell
having a relatively wide coverage, such as a cell configured by a
conventional eNB, and a "macro eNB" refers to an eNB configuring a
macro cell. A "small cell" refers to a cell having a relatively
narrow coverage, such as a downsized cell, and a "small eNB" refers
to an eNB configuring a small cell.
[0140] The macro eNB may be, for example, a "wide area base
station" described in Non-Patent Document 7.
[0141] The small eNB may be, for example, a low power node, local
area node, or hotspot. Alternatively, the small eNB may be a pico
eNB configuring a pico cell, a femto eNB configuring a femto cell,
HeNB, remote radio head (RRH), remote radio unit (RRU), remote
radio equipment (RRE), or relay node (RN). Still alternatively, the
small eNB may be a "local area base station" or "home base station"
described in Non-Patent Document 7.
[0142] FIG. 7 shows the concept of the cell configuration in which
macro eNBs and small eNBs coexist. The macro cell configured by a
macro eNB has a relatively-wide-range coverage 701. A small cell
configured by a small eNB has a coverage 702 whose range is
narrower than that of the coverage 701 of a macro eNB (macro
cell).
[0143] When a plurality of eNBs coexist, the coverage of the cell
configured by an eNB may be included in the coverage of the cell
configured by another eNB. In the cell configuration shown in FIG.
7, as indicated by a reference "704" or "705", the coverage 702 of
the small cell configured by a small eNB may be included in the
coverage 701 of the macro cell configured by a macro eNB.
[0144] As indicated by the reference "705", the coverages 702 of a
plurality of, for example, two small cells may be included in the
coverage 701 of one macro cell. A user equipment (UE) 703 is
included in, for example, the coverage 702 of the small cell and
performs communication via the small cell.
[0145] In the cell configuration shown in FIG. 7, as indicated by a
reference "706", the coverage 701 of the macro cell configured by a
macro eNB may overlap the coverages 702 of the small cells
configured by small eNBs in a complicated manner.
[0146] As indicated by a reference "707", the coverage 701 of the
macro cell configured by a macro eNB may not overlap the coverages
702 of the small cells configured by small eNBs.
[0147] Further, as indicated by a reference "708", the coverages
702 of a large number of small cells configured by a large number
of small eNBs may be configured in the coverage 701 of one macro
cell configured by one macro eNB.
[0148] 5G proposes that a base station (a 5G base station will be
referred to as a gNB in this Description) should communicate with
application of beamforming for forming narrow beams using a
plurality of antennas to broaden a radio coverage, i.e., a
coverage. For example, the gNB includes a multi-element antenna as
the antenna 408 illustrated in FIG. 4. The gNB forms a beam in a
predefined direction, using a part of the multi-element antenna or
all of a plurality of antennas. Forming the narrow beams can
broaden the radio coverage. A proposal is made on a method for
performing the beam sweeping with different timings using one or
more beams to cover a wide coverage when the number of beams formed
by the gNB at a time is less and a coverage necessary for a cell
cannot be covered (see Non-Patent Document 12).
[0149] FIG. 8 illustrates the beam sweeping. To perform the beam
sweeping, downlink beam sweeping blocks (DL sweeping blocks) 801
and uplink beam sweeping blocks (UL sweeping blocks) 803 are
provided. DL/UL data subframes 805 in which the downlink data and
the uplink data are to be transmitted are interposed between the
downlink beam sweeping blocks 801 and the uplink beam sweeping
blocks 803.
[0150] As indicated by a reference 811, the block 801 and the block
803 include a plurality of resources 802, and a plurality of
resources 804 and 806, respectively. Each of the resources is
transmitted via a beam denoted by a reference 812.
[0151] The downlink beam sweeping block 801 is repeatedly
transmitted with a predefined downlink sweeping block period
T.sub.sbp. In the downlink beam sweeping block 801, beams are
formed and transmitted for a predefined narrow coverage during a
first predefined duration, and beams are formed and transmitted for
the next predefined narrow coverage during the next predefined
duration. With repetition of this, all coverages for a cell are
covered. The resources denoted by the reference 802 are used for
transmitting, for example, a synchronization signal, the PBCH, and
a beam reference signal.
[0152] In the uplink beam sweeping block 803, beams are formed and
received for a predefined narrow coverage during a first predefined
duration, and beams are formed and received for the next predefined
narrow coverage during the next predefined duration. With
repetition of this, all coverages for a cell are covered. The
resources denoted by the reference 804 are used for transmitting,
for example, the RACH.
[0153] A series of beam sweepings during covering of all the
coverages for the cell will be referred to as beam sweeping blocks.
In the following description, a transmission/reception duration of
each beam in the beam sweeping blocks may be referred to as a "beam
unit".
[0154] The beam sweeping block is periodically provided. In the
downlink beam sweeping block 801, a common control signal and a
channel are transmitted via each of the beams. Examples of the
common control signal and the channel include a synchronization
signal (SS), the PBCH, and a reference signal (RS) that are common
control signals necessary for initial access. In the uplink beam
sweeping block 803, RACH resources, etc. are allocated to each of
the beams.
[0155] A UE 813 performs reception during the entire duration of
the downlink beam sweeping blocks 801. Consequently, wherever being
located in the coverage for the cell, the UE 813 can receive beams
transmitted to its position. Thus, the UE 813 can receive, for
example, the common control signal necessary for initial access.
The UE 813 performs transmission in the uplink beam sweeping blocks
803. Consequently, the gNB can receive the uplink transmission from
the UE 813. The UE 813 transmits and receives uplink data/downlink
data to and from the gNB, using the beams in the DL/UL data
subframes 805.
[0156] As described above, the UE finds a beam that can be
transmitted and received by its own UE using the beam sweeping, and
uses the beam for communication with the gNB. When the gNB uses a
beam different from the beam, the UE need not receive the downlink
signal.
[0157] However, the UE does not know with which timing the gNB
transmits and receives data for the UE. Thus, the UE needs to
receive the downlink control signal to be transmitted from the gNB
in each subframe to determine whether to transmit and receive the
uplink/downlink user data to and from the gNB. Reception of the
downlink control signal from the gNB in each subframe by the UE
will waste the power consumption of the UE, and the frequency and
the time resources to be used for the reception.
[0158] 3GPP R1-1609135 (hereinafter referred to as "Reference 1")
proposes receiving the downlink control signal with a period longer
than that per scheduling. Furthermore, 3GPP R1-1610240 (hereinafter
referred to as "Reference 2") proposes allocating, to each beam,
the timing with which the gNB transmits the downlink control
signal.
[0159] The aforementioned methods require the UE to perform an
operation of periodically receiving the downlink control signal
even when the gNB does not transmit the downlink control signal
with the period. Thus, the operation of receiving the downlink
control signal by the UE will cause a problem of wasting the power
consumption. The aforementioned methods also have a problem of
increase in the latency in the communication between the gNB and
the UE. This is because even when the gNB retransmits the downlink
control signal according to the HARQ, the UE needs to wait for the
retransmission until the next period. Moreover, the aforementioned
methods do not consider any method for setting the period.
[0160] The first embodiment will disclose a method for solving such
problems.
[0161] The gNB notifies the UE of the next timing with which the UE
needs to perform an operation of receiving the PDCCH (hereinafter
will be referred to as a "PDCCH reception timing"). The PDCCH
reception timing may be a timing with which the gNB probably
transmits the downlink control information to the UE, a timing with
which the gNB probably schedules transmission and reception of the
uplink/downlink data for the UE, or a timing with which the gNB
directs a beam toward the UE. The gNB may notify, with the PDCCH
reception timing, the UE of scheduling information for transmitting
and receiving the uplink/downlink data. The gNB may transmit and
receive the uplink/downlink data to and from the UE. The UE
performs the operation of receiving the PDCCH from the gNB with the
PDCCH reception timing. The UE may receive the downlink control
information for its own UE from the gNB. The UE may transmit and
receive the uplink/downlink data to and from the gNB.
[0162] The gNB may notify the PDCCH reception timing using a
downlink control signal. The downlink control signal may be
notified via the L1/L2 signaling. Application of the L1/L2
signaling enables prompt notification of the PDCCH reception
timing.
[0163] Alternatively, the gNB may notify the PDCCH reception timing
via the MAC control signal. Since the retransmission control
according to the HARQ is performed with application of the MAC
control signal, the PDCCH reception timing can be notified with
high reliability.
[0164] The UE may perform the operation of receiving the PDCCH in
each subframe, until receiving the notification of the PDCCH
reception timing. The gNB may notify the PDCCH reception timing
after the RRC connection establishment with the UE, during the RRC
connection establishment process, or in a random access procedure.
When the PDCCH reception timing is notified in the random access
procedure, information on the PDCCH reception timing may be
included in a random access response to be notified.
[0165] Information indicating a subframe number may be notified as
the PDCCH reception timing. The information indicating the subframe
number may be, for example, the subframe number or a remainder
obtained by dividing the subframe number by a predefined divisor.
The predefined divisor may be defined in a standard, broadcast from
the gNB to the UE, or notified individually via the RRC-dedicated
signaling.
[0166] Alternatively, the time from the current subframe may be
notified as the PDCCH reception timing. The time from the current
subframe may be a time per subframe or another unit.
[0167] The gNB may predefine several options for the PDCCH
reception timing, and notify the UE of an identifier of a selected
value. The options may be defined in a standard, or notified from
the gNB to the UE in advance. The options may be broadcast to the
UEs being served by the gNB, or notified individually to each of
the UEs. The individual notification may be made via the
RRC-dedicated signaling. Since the gNB can notify the UE of an
identifier of a value selected from the options as the PDCCH
reception timing by individually notifying the options, it can
notify the PDCCH reception timing with less number of bits.
[0168] The gNB may set a plurality of PDCCH reception timings to
the UE. Even when the PDCCH cannot be transmitted from the gNB to
the UE with a PDCCH reception timing, the UE has only to perform
the operation of receiving the PDCCH with the next PDCCH reception
timing. Thus, the received power of the UE until the next PDCCH
reception timing can be saved.
[0169] When the gNB sets the plurality of PDCCH reception timings
to the UE, one piece of downlink control information may include
information on the plurality of PDCCH reception timings, or a
plurality of downlink control information may be multiplexed to be
notified.
[0170] Alternatively, a plurality of downlink control information
each including a plurality of PDCCH reception timings may be used.
An upper limit may be set to the number of PDCCH reception timings
in one piece of the downlink control information. The upper limit
may be defined in a standard. Consequently, the gNB can notify the
UE of a plurality of PDCCH reception timings while the size of one
piece of the downlink control information is reduced to less than
or equal to a constant. Thus, the process of receiving the downlink
control information in the UE is simplified.
[0171] In setting the plurality of PDCCH reception timings, the gNB
and the UE may validate both of the PDCCH reception timing
previously notified to the UE and the PDCCH reception timing
subsequently notified to the UE. Consequently, the number of PDCCH
reception timings to be subsequently notified to the UE can be
reduced.
[0172] Alternatively, the gNB and the UE may invalidate the PDCCH
reception timing previously notified to the UE and validate the
PDCCH reception timing subsequently notified to the UE.
Consequently, control over the operation of receiving the PDCCH in
the UE can be simplified, and the power consumption in the
operation of receiving the PDCCH in the UE can be reduced.
[0173] Whether to validate the PDCCH reception timing previously
notified to the UE may be defined in a standard or notified from
the gNB to the UE in advance. Alternatively, information indicating
whether to validate the PDCCH reception timing previously notified
to the UE may be included in the notification of the PDCCH
reception timing to be subsequently notified to the UE. For
example, including such information in the notification of the
PDCCH reception timing to be subsequently notified to the UE
enables flexible control over the PDCCH reception timings.
[0174] FIG. 9 illustrates one example where the gNB notifies the UE
of the next timing with which the PDCCH needs to be received and
the UE transmits and receives the uplink/downlink data. FIG. 9
illustrates notification of the next transmission/reception timing
of the UE using the downlink control information transmitted from
the gNB to the UE. Portions denoted by references 902, 906, and 910
in FIG. 9 represent downlink control signals that the UE receives
from the gNB. Portions denoted by references 903, 907, and 911
represent pieces of user data to be transmitted and received by the
UE. Thick solid-line arrows 904, 908, and 912 each represent
information on a subframe indicated by the next PDCCH reception
timing. The downlink control signals 902, 906, and 910 may or may
not include scheduling information for transmitting and receiving
the pieces of user data 903, 907, and 911, respectively, in the
corresponding subframes. FIG. 9 illustrates a case where the
downlink control signals 902, 906, and 910 include the scheduling
information for transmitting and receiving the pieces of user data
903, 907, and 911, respectively, in the corresponding
subframes.
[0175] In FIG. 9, the UE receives the downlink control signal 902
in a subframe 901. The UE obtains, from the downlink control signal
902, the scheduling information for transmitting and receiving the
piece of user data 903 in the subframe 901, and the information 904
on the next PDCCH reception timing. The UE transmits and receives
the piece of user data 903 to and from the gNB. The scheduling
information included in the downlink control signal 902 is used for
transmitting and receiving the piece of user data 903.
[0176] In FIG. 9, the information 904 on the next PDCCH reception
timing indicates a subframe 905 as the next PDCCH reception timing
of the UE. The UE receives the downlink control signal 906 in the
subframe 905. The UE obtains, from the received downlink control
signal 906, information on the piece of user data 907 in the
subframe 905, and the information 908 on the next PDCCH reception
timing. The UE transmits and receives the piece of user data 907 to
and from the gNB. The scheduling information included in the
downlink control signal 906 is used for transmitting and receiving
the piece of user data 907.
[0177] In FIG. 9, the information 908 on the next PDCCH reception
timing indicates a subframe 909 as the next PDCCH reception timing
of the UE. Since the subsequent procedure is the same as that
previously described, the description will be omitted.
[0178] The gNB may include another downlink control information in
the PDCCH including the downlink control information indicating the
next PDCCH reception timing. Examples of the other downlink control
information may include information on scheduling of the
uplink/downlink data, a request for transmitting the CQI, and an
instruction for the UE to control power.
[0179] Alternatively, the gNB may not include the other downlink
control information in the PDCCH including the downlink control
information indicating the next PDCCH reception timing for the UE.
Consequently, the UE can receive the next PDCCH reception timing
from the gNB, even in the absence of, for example, transmission and
reception of the uplink/downlink data that the gNB should transmit
and receive with the timing and any other downlink control
information that should be transmitted from the gNB to the UE.
Thus, the UE need not perform any unnecessary operation of
receiving the PDCCH.
[0180] The gNB may notify a plurality of UEs that perform
transmission and reception using the same beam of the next PDCCH
reception timing. The plurality of UEs may or may not be all the
UEs that perform transmission and reception using the beam. The
timing may be notified via the L1/L2 signaling. The timing may be
notified to each of the plurality of UEs, or simultaneously
notified to all the UEs that use the beam.
[0181] An identifier indicating the beam may be used when the
timing is simultaneously notified to all the UEs that use the beam.
The identifier may be used, for example, in a process of coding the
downlink control information. Alternatively, the identifier may be
used in a process of modulating the downlink control information.
The identifier may be used in both the coding process and the
modulating process.
[0182] The gNB may multiplex the downlink control signals for a
plurality of UEs to transmit the resulting signal. The multiplexing
may be used when the timing is notified to each of the plurality of
UEs. The multiplexing may be frequency multiplexing, time
multiplexing, or a combination of the frequency multiplexing and
the time multiplexing. The multiplexing method may be defined in a
standard, broadcast from the gNB to the UEs being served thereby in
advance, or notified to each of the UEs.
[0183] When the timing is notified to each of the plurality of UEs,
the gNB may notify the UEs of the same timing or different timings.
Notifying a plurality of UEs of the same value enables the gNB to
perform flexible scheduling of the plurality of UEs. Even in the
absence of transmission and reception of the user data to and from
a predefined UE in the beam with the timing, the transmission and
reception of the user data with the timing can be allocated to the
other UEs in the beam. Consequently, the frequency resources can be
efficiently used with the timing.
[0184] The gNB may multiplex the downlink control signal for the
other UEs with an uplink/downlink signal to be transmitted and
received to and from the UE. The uplink/downlink signal may include
the downlink control signal for the UE. The multiplexing may be
frequency multiplexing, time multiplexing, or a combination of the
frequency multiplexing and the time multiplexing. The multiplexing
method may be defined in a standard, broadcast from the gNB to the
UEs being served thereby in advance, or notified to each of the
UEs. Consequently, the gNB can, for example, notify the next PDCCH
reception timing of the other UEs as well as transmitting and
receiving the uplink/downlink data to and from the UE and notifying
the next PDCCH reception timing of the UE. Thus, the frequency
resources and the time resources can be efficiently used.
[0185] The gNB may not transmit the PDCCH to the UE with the next
PDCCH reception timing of the UE. The gNB may not perform
uplink/downlink transmission and reception to and from the UE.
Consequently, the gNB can reduce the power consumption in the
absence of data to be transmitted and received to and from the
UE.
[0186] The following (1) to (11) will be disclosed as specific
examples of information necessary for the gNB to determine the next
PDCCH reception timing of the UE:
[0187] (1) a channel state, for example, CQI/CSI;
[0188] (2) variations in a channel state, for example, variations
in CQI/CSI;
[0189] (3) buffer occupancy;
[0190] (4) variations in buffer occupancy;
[0191] (5) target Quality of Service (target QoS);
[0192] (6) a difference between the target Quality of Service and
the actual Quality of Service;
[0193] (7) information on the UEs in a beam, for example, the
number of UEs in the beam;
[0194] (8) a throughput of the user data to be transmitted from a
master eNB to its own gNB;
[0195] (9) a throughput of the user data to be transmitted from a
high-level network device to its own gNB;
[0196] (10) a throughput of the user data to be transmitted from
its own gNB to a secondary eNB; and
[0197] (11) combinations of (1) to (10) above.
[0198] Regarding (1), the gNB may set longer a duration until the
timing to the UE when the CQI/CSI to be notified from the UE is
inferior. The gNB may set shorter the duration until the timing
when the CQI/CSI is superior. Thereby, the gNB may frequently
allocate the transmission/reception timing to the UE whose CQI/CSI
is superior. Consequently, a throughput of the whole system can be
increased. Alternatively, the gNB may set shorter the duration
until the timing, for example, when the CQI/CSI is inferior. Since
the time for the UE from the initial transmission to the
retransmission according to the HARQ can be shortened, the latency
caused by the HARQ retransmission can be reduced.
[0199] Regarding (2), the gNB sets shorter the duration until the
timing to the UE when, for example, the variations in CQI/CSI to be
notified from the UE are larger, so that the scheduling by the gNB
can promptly follow variations in a communication channel.
[0200] Regarding (3), the gNB may use the buffer occupancy for
downlink communication or for uplink communication. The buffer
occupancy for uplink communication may be obtained from a Buffer
Status Report (BSR) to be notified from the UE to the gNB, or may
be another value.
[0201] Regarding (3), for example, when the buffer occupancy in the
UE is greater, the gNB sets shorter the duration until the timing
to the UE. Since this increases the communication between the gNB
and the UE, a buffer overflow in the UE can be prevented.
[0202] The buffer occupancy in (3) may be, for example, a relative
value of a buffer occupancy of data for another UE in the downlink
communication, or a relative value of a buffer occupancy of another
UE in the uplink communication. Since application of the relative
value enables setting shorter the duration until the timing to the
UE whose buffer occupancy is greater, a buffer overflow in the UE
whose buffer occupancy is greater can be prevented.
[0203] Regarding (4), the gNB sets shorter the duration until the
timing to the UE when, for example, the buffer occupancy in the UE
is increasing, so that the scheduling by the gNB can promptly
follow increase in the buffer occupancy.
[0204] Regarding (5), setting shorter the duration until the timing
to the UE that communicates using, for example, the Ultra Reliable
and Low Latency Communication (URLLC) service can reduce the
latency in the UE.
[0205] Regarding (6), when a predefined communication rate cannot
be maintained for the UE that communicates using, for example, the
enhanced Mobile BroadBand (eMBB) service, the duration until the
timing may be set shorter. This can increase the communication rate
in the UE and maintain the predefined communication rate.
[0206] Regarding (7), for example, when many UEs are in a coverage
of a beam, a throughput of each of the UEs can be maintained by
setting shorter the duration until the timing to the UE.
[0207] Regarding (8), the gNB sets shorter the duration until the
timing, for example, to the UEs being served thereby when the user
data to be received by the gNB from the master eNB is increasing in
the DC, so that the gNB can transmit the user data to the UEs
without retaining the user data. Although the master eNB is a LTE
base station herein, it may be replaced with a 5G base station,
that is, it may be a base station to be a master in the DC, for
example, a master gNB.
[0208] Regarding (9), the gNB sets shorter the duration until the
timing, for example, when the user data to be received by the gNB
from the high-level network device is increasing, so that the gNB
can transmit the user data to the UE without retaining the user
data. Here, the gNB may apply the configuration of the DC. The gNB
may be a master base station in the configuration of the DC. The
high-level network device may be a high-level network device in the
LTE or in the 5G.
[0209] Regarding (10), the duration until the timing may be set
shorter, for example, when the gNB is a master base station in the
DC and the throughput of the user data to be transmitted from the
gNB to the secondary eNB is decreasing. Consequently, the occupancy
in the gNB can be reduced when the gNB transmits the user data to
the UE. Here, the secondary eNB may be replaced with a 5G base
station, that is, it may be a secondary base station in the DC, for
example, a secondary gNB.
[0210] For example, (3) and (7) are combined in (11), a sum of
buffer occupancies of the UEs using a beam is calculated, and the
duration until the timing is set shorter to a UE using the beam and
whose sum of buffer occupancies is greater. Consequently, a buffer
overflow in the communication with the UE using the beam can be
prevented.
[0211] For example, (9) and (10) are combined in (11), and the
duration until the timing may be set shorter when a value is
increasing: the value is obtained, for example, in a DC
configuration where the gNB is a master base station, by
subtracting a throughput of the user data to be transmitted from
the gNB to the secondary eNB, from a throughput of the user data to
be transmitted from the high-level network device to its own gNB.
Since the timing can be set using the amount of data to be stored
in the gNB, the user data can be transmitted to the UE while the
occupancy in the gNB is reduced.
[0212] When the gNB notifies the UE of the next PDCCH reception
timing, the gNB may notify the UE of the PDCCH reception timing for
a predefined duration. There may be a plurality of PDCCH reception
timings. The gNB may determine the transmission/reception timing
for the duration. The UE performs transmission and reception to and
from the gNB with the timing. Consequently, the gNB need not notify
the UE of the PDCCH reception timing every time. Even when the gNB
cannot communicate with the UE with a PDCCH reception timing, the
gNB can communicate with the UE with the next PDCCH reception
timing.
[0213] The gNB may notify the UE of the predefined duration.
Examples of the predefined duration may include the number of times
data is transmitted and received to and from the UE until
expiration, the number of subframes until the expiration, and the
subframe number upon the expiration.
[0214] The gNB may notify the UE of the predefined duration and the
PDCCH reception timing separately. Alternatively, the gNB may
notify the UE of the predefined duration and the PDCCH reception
timing simultaneously. The gNB may notify the predefined duration
and the PDCCH reception timing, using the same downlink control
information or different pieces of downlink control information.
The UE may update the predefined duration or the PDCCH reception
timing with the notification.
[0215] The gNB may directly notify the UE of a value indicating the
predefined duration, or predefine several options and notify the UE
of an identifier of a selected value. The options may be defined in
a standard, or notified from the gNB to the UE in advance. The
options to be notified may be broadcast to the UEs being served by
the gNB, or notified individually to each of the UEs. The
individual notification may be made via the RRC-dedicated
signaling. Since the gNB can notify the UE of an identifier of a
value selected from the options as the duration, it can notify the
duration with less number of bits.
[0216] The gNB may notify the UE of the PDCCH reception timings in
bitmap format. For example, assuming that the number of subframes
until the predefined duration is 10 and that the timing after 1
subframe, the timing after 3 subframes, the timing after 6
subframes, and the timing after 8 subframes are designated as the
PDCCH reception timings, the bitmap to be notified to the UE may be
1010010100, where 1 denotes a bit corresponding to each of the
timings, and 0 denotes the other bits. Consequently, the PDCCH
reception timings can be notified with less number of bits. In the
bit map, 1 and 0 may be reversed.
[0217] The gNB may be able to change the duration and the PDCCH
reception timing for the UE. The gNB may semi-statically or
dynamically change the duration and the PDCCH reception timing. The
gNB may notify the UE of the duration and the PDCCH reception
timing with each PDCCH reception timing for the UE, only when
changing the PDCCH reception timing during the duration, or when
updating the duration. The gNB preferably updates the duration and
the PDCCH reception timing for the UE before expiration of the
duration. Consequently, the power waste caused by the UE performing
the operation of receiving the PDCCH in each subframe can be
avoided. Alternatively, the gNB may notify the UE of the duration
and the PDCCH reception timing soon after expiration of the
duration.
[0218] The gNB may semi-statically or dynamically notify the UE of
the duration and the PDCCH reception timing. The semi-static
notification may be made via, for example, the RRC-dedicated
signaling. The dynamic notification may be made, for example, via
the MAC control signal or via the L1/L2 signaling. The duration and
the PDCCH reception timing may be notified using the same method or
different methods. Alternatively, both of the methods may be used
in combination. For example, the gNB notifies the UE of the
duration via the RRC-dedicated signaling and of the PDCCH reception
timing via the L1/L2 signaling. Consequently, the dynamic change in
the timing during the duration can be made with less amount of
signaling.
[0219] The aforementioned (1) to (11) disclosed as the specific
examples of the information necessary for determining the
transmission/reception timing may be used as information necessary
for the gNB to determine the duration and the PDCCH reception
timing.
[0220] FIG. 10 illustrates one example where the gNB notifies the
UE of the PDCCH reception timing for a predefined duration and the
UE transmits and receives the uplink/downlink data. FIG. 10
illustrates notification of the duration and the PDCCH reception
timing using the downlink control information transmitted from the
gNB to the UE. Portions denoted by references 1001 and 1007 in FIG.
10 represent downlink control signals for notifying the predefined
duration and the PDCCH reception timing for the UE, among downlink
control signals that the UE receives from the gNB.
[0221] Portions denoted by references 1003, 1005, and 1009
represent the downlink control signals that the UE receives from
the gNB. Portions denoted by references 1002, 1004, 1006, 1008, and
1010 represent pieces of user data that the UE transmits and
receives to and from the gNB. Thick solid-line arrows represent
information on the PDCCH reception timing of the UE. A thick dotted
line represents a predefined duration TO. A thick alternate long
and short dashed line represents information on the predefined
duration TO in the downlink control signal. Thin solid-line arrows
represent scheduling information for transmitting and receiving the
pieces of user data in the subframes. The downlink control signals
1001, 1003, 1005, 1007, and 1009 may or may not include the
scheduling information for transmitting and receiving the pieces of
user data 1002, 1004, 1006, 1008, and 1010, respectively, in the
corresponding subframes. FIG. 10 illustrates the case where the
downlink control signals 1001, 1003, 1005, 1007, and 1009 include
the scheduling information for transmitting and receiving the
pieces of user data 1002, 1004, 1006, 1008, and 1010, respectively,
in the corresponding subframes.
[0222] In FIG. 10, the UE receives the downlink control signals
1001, 1003, 1005, 1007, and 1009. Among them, the downlink control
signals 1001 and 1007 store not only the scheduling information for
transmitting and receiving the pieces of user data in the
subframes, but also information on the predefined duration and
information on the PDCCH reception timing during the predefined
duration. The UE obtains PDCCH reception information, and receives
the downlink control signals 1003, 1005, and 1009 that are
subsequent to the downlink control signals 1001 and 1007 that store
the obtained information. The UE transmits and receives the pieces
of user data 1002, 1004, 1006, 1008, and 1010, using the scheduling
information obtained from the downlink control signals 1001, 1003,
1005, 1007, and 1009, respectively.
[0223] In FIG. 10, the gNB may notify the UE of the PDCCH reception
timings in the downlink control signals 1003, 1005, and 1009. The
gNB may also notify the predefined duration. This increases the
redundancy in the notification of the PDCCH reception timing for
the UE. Thus, the reliability for notification of the PDCCH
reception timing can be improved.
[0224] In FIG. 10, the gNB may not notify the UE of the PDCCH
reception timings in the downlink control signals 1003, 1005, and
1009. Consequently, the number of bits of the downlink control
signals can be saved.
[0225] For another example of notification of the PDCCH reception
timing from the gNB to the UE, the gNB may notify the UE of a
timing with which an operation of receiving the PDCCH from the gNB
is unnecessary (hereinafter will be referred to as a "PDCCH
reception unnecessary timing"). The gNB may notify the PDCCH
reception unnecessary timing together with the predefined duration.
The UE may perform the operation of receiving the PDCCH from the
gNB, in a subframe excluding the PDCCH reception unnecessary
timing.
[0226] Similarly as in the notification of the PDCCH reception
timing during the predefined duration, the PDCCH reception
unnecessary timing may be notified as a subframe number, as the
number of subframes counted from the current time, or in bitmap
format.
[0227] The gNB may designate, as the PDCCH reception unnecessary
timing, a subframe in which scheduling for the other UEs has
already been determined. Consequently, the gNB can perform flexible
scheduling for the UE within the subframes excluding the PDCCH
reception unnecessary timing.
[0228] For another example of notification of the PDCCH reception
timing from the gNB to the UE, the gNB may set a PDCCH reception
period to the UE. The PDCCH reception period may be notified per
subframe or per another unit. The first embodiment differs from
Reference 1 in disclosing a method for setting the PDCCH reception
period.
[0229] In setting the PDCCH reception period, the gNB may also set
a validity period of the PDCCH reception period to the UE. The
validity period may be set similarly as setting the predefined
duration.
[0230] The gNB may notify the UE of an offset of the PDCCH
reception timing together with the PDCCH reception period. The
offset may be notified as a subframe number, as a remainder
obtained by dividing the subframe number by the period, or a time
until the next PDCCH reception timing in the UE. The time may be
notified per subframe or per another unit.
[0231] The gNB may notify the UE of a timing with which the PDCCH
reception period and the offset are validated, together with the
PDCCH reception period and the offset. The gNB may notify the
timing to be validated as a subframe number or a time from the
notification to the validation.
[0232] The gNB may notify the UE of the PDCCH reception period, the
offset, and the timing to be validated separately or of at least
two of the PDCCH reception period, the offset, and the timing to be
validated simultaneously.
[0233] The gNB may directly notify the UE of a value indicating the
PDCCH reception period, or predefine several options and notify the
UE of an identifier of a selected value. The options may be defined
in a standard, or notified from the gNB to the UE in advance. The
options to be notified may be broadcast to the UEs being served by
the gNB, or notified individually to each of the UEs. The
individual notification may be made via the RRC-dedicated
signaling. Since the gNB can notify the UE of an identifier of a
value selected from the options as the PDCCH reception period by
individually notifying the options, it can notify the PDCCH
reception period with less number of bits. The same may hold true
for the offset and the timing to be validated.
[0234] The gNB may semi-statically or dynamically notify the UE of
the PDCCH reception period, the offset, and the timing to be
validated. The semi-static notification may be made via, for
example, the RRC-dedicated signaling. The dynamic notification may
be made, for example, via the MAC control signal or via the L1/L2
signaling. The PDCCH reception period, the offset, and the timing
to be validated may be notified using the same method or different
methods. Alternatively, both of the methods may be used in
combination.
[0235] The gNB may notify the UE of the PDCCH reception timing in a
predefined period. The notification may be made using, for example,
a bitmap. In the bitmap, the predefined period may be represented
by the number of bits. Furthermore, "1" may be associated with the
PDCCH reception timing, and "0" may be associated with the other
subframes. The positions of the bits may be associated with
remainders each obtained by dividing the subframe number by the
predefined period. For example, when the predefined period is 4
subframes and the remainders obtained by dividing the subframe
numbers by the predefined period are 0, 1, and 3 as the PDCCH
reception timings of the UE, the gNB may notify the UE of "1101" as
the bitmap. Consequently, allocation of the PDCCH reception timing
from the gNB to the UE can be performed flexibly.
[0236] The gNB may distribute the PDCCH reception timings to
different UEs in different proportions.
[0237] For example, assuming a subframe whose remainder obtained by
dividing the subframe number by 3 is 0 or 1 as the PDCCH reception
timing of the UE #1, a subframe whose remainder obtained by
dividing the subframe number by 6 is 4 as the PDCCH reception
timing of the UE #2, and a subframe whose remainder obtained by
dividing the subframe number by 6 is 5 as the PDCCH reception
timing of the UE #3, bitmaps that the gNB notifies the UE #1, the
UE #2, and the UE #3 may be "110", "000010", and "000001",
respectively. Consequently, the PDCCH reception timings can be
allocated flexibly to the different UEs.
[0238] The aforementioned (1) to (11) disclosed as the specific
examples of the information necessary for determining the PDCCH
reception timing may be used as information necessary for the gNB
to determine the predefined period, the offset, and the timing to
be validated.
[0239] The UE may perform the operation of receiving the PDCCH
transmitted from the gNB in each subframe. The trigger for the UE
to perform the operation of receiving the PDCCH in each subframe
may be, for example, a lapse of the PDCCH reception timing of the
UE, the absence of the PDCCH reception timing of the UE, the
expiration of the predefined duration, failure of normal receipt of
the downlink control signal from the gNB, or failure of normal
receipt of the downlink user data from the gNB. The operation of
receiving the PDCCH in each subframe by the UE enables the UE to
receive the downlink control signal for its own UE from the gNB and
restore or continue the communication with the gNB.
[0240] The gNB may retransmit the downlink user data for the UE
with the PDCCH reception timing next to transmission of the initial
transmission data. Alternatively, the gNB may perform the
retransmission to the UE in a subframe next to the timing with
which the initial transmission data has been transmitted,
regardless of the next PDCCH reception timing. The UE may receive
the retransmission with the PDCCH reception timing next to the
initial transmission, or in a subframe next to that for the initial
transmission. Alternatively, the UE may receive the retransmission
data from the gNB through reception of the PDCCH in each subframe.
The gNB performs retransmission in a subframe next to that for the
initial transmission, which can reduce the latency for Nack in the
communication between the gNB and the UE. For example, when the UE
cannot successfully receive the RRC signaling or the MAC control
information to be used for notification of the next PDCCH reception
timing, the UE can obtain the PDCCH reception timing in the next
subframe.
[0241] The gNB may notify, in advance, the UE of information
indicating whether the gNB uses, for retransmission, the subframe
next to that for the initial transmission. Alternatively, the
information may be defined in a standard. The gNB may make the
notification by broadcasting it to the UEs being served thereby or
by transmitting the RRC-dedicated signaling to the UE. The UE may
determine, using the notification, whether to receive the
retransmission in the subframe next to that for the initial
transmission.
[0242] The gNB may determine whether to apply the subframe next to
that for the initial transmission to the retransmission to the UE,
using information on the beam of which coverage the UE is in. The
information on the beam may be, for example, the number of UEs that
are in a coverage of the beam. For example, when many UEs are in a
coverage of the beam, the subframe next to that for the initial
transmission may not be applied to the retransmission to the UE.
This can prevent, for example, retransmission to the UE from
causing congestion of data to be transmitted and received to and
from the other UEs.
[0243] For another example, the gNB may determine whether to apply
the subframe next to that for the initial transmission to the
retransmission to the UE, using information on a service to be
adopted by the UE. For example, when the UE uses a URLLC service,
the subframe next to that for the initial transmission may be
applied to the retransmission to the UE. Consequently, requirements
in a service to be adopted by the UE, for example, the low latency
in URLLC can be satisfied.
[0244] The retransmission to the UE may be performed in the
subframe after the designated subframes, instead of the subframe
next to that for the initial transmission. Consequently, even when
the gNB performs retransmission to the UE, communication with the
other UEs can be continued.
[0245] The values of the designated subframes may be determined in
a standard, broadcast from the gNB to the UEs being served thereby,
or notified to each of the UEs via the RRC signaling. The gNB may
determine the values of the designated subframes, using information
on the beam to be used by the UE or using information on the
service to be adopted by the UE.
[0246] The gNB may perform transmission and reception with the
other UEs with the next PDCCH reception timing of the UE. The
transmission and reception with the other UEs may mean, for
example, retransmission from the other UEs or communication with
high priority. The priority may be determined in a standard or
determined by the gNB, depending on, for example, a type of the
service to be adopted by the UE.
[0247] The gNB may not transmit, with the PDCCH reception timing,
the L1/L2 signaling to the UE, that is, to the UE interrupted by
the other UEs with the PDCCH reception timing. The UE may return to
operations of consecutively receiving the PDCCH in each subframe,
or perform the operation of receiving the PDCCH from the gNB with a
PDCCH reception timing next to the PDCCH reception timing.
[0248] The gNB may notify the UE of the PDCCH reception timing
after the next. The notification may be made via the L1/L2
signaling. The gNB may multiplex the L1/L2 signaling for the UE
with the L1/L2 signaling for the other UEs to transmit the
resulting L1/L2 signaling. The multiplexing may be, for example,
time multiplexing using different symbols, spatial multiplexing
using a plurality of beams, or both the time multiplexing and the
spatial multiplexing in combination. In the time multiplexing, the
L1/L2 signaling for the UE may precede the L1/L2 signaling for the
other UEs, or the L1/L2 signaling for the other UEs may precede the
L1/L2 signaling for the UE. Which one of the L1/L2 signalings the
gNB determines to use earlier may be predefined in a standard. Each
of the UE and the other UEs may receive the L1/L2 signaling for its
own UE from the gNB based on the standard.
[0249] The gNB may notify the UE of the next PDCCH reception timing
using a beam sweeping block. The gNB may also notify an identifier
indicating the UE together with the timing when notifying the
timing using the beam sweeping block. The UE may obtain the next
PDCCH reception timing by receiving the beam sweeping block. The UE
may receive the beam sweeping block upon interruption of the other
UEs with the PDCCH reception timing as a trigger, or may always
receive the beam sweeping block. Upon obtainment of the PDCCH
reception timing from the beam sweeping block as a trigger, the UE
may stop receiving the PDCCH consecutively in each subframe. Since
the UE need not receive the PDCCH consecutively in each subframe
after the beam sweeping block, the power consumption of the UE can
be reduced.
[0250] The gNB may notify a UE different from the UE of the PDCCH
reception timing using a beam sweeping block. The notification to
the different UE is preferably made using a beam sweeping block
earlier than the next PDCCH reception timing for the different UE.
Consequently, the different UE can perform transmission and
reception with the gNB with the timing earlier than the PDCCH
reception timing of its own UE.
[0251] Reception of the downlink control information by the UE with
a designated timing, periodical reception of the downlink control
information by the UE, and reception of the downlink control
information by the UE in each subframe that are described in the
first embodiment may be switchable. The gNB may notify the UE of an
instruction for switching between the methods for receiving a
downlink control channel. Upon the notification, the UE may switch
between the methods for receiving the downlink control information.
The notification may include an identifier indicating one of the
reception methods. The gNB may make the notification to the UE
semi-statically via the RRC-dedicated signaling, dynamically via
the MAC control signal, or dynamically via the L1/L2 signaling.
[0252] The methods described in the first embodiment may be applied
to the communication of the uplink data. Here, the details to be
notified from the gNB to the UE may be the same as those in the
communication of the downlink data. The uplink grant may also be
notified to the UE in the communication of the uplink data.
[0253] The gNB may notify the UE of Ack/Nack with the PDCCH
reception timing next to reception of the initial transmission data
by the UE. The gNB may notify the UE of Ack/Nack and the grant
simultaneously or separately. The UE may transmit, using the
Ack/Nack notification and the grant, the uplink data to the gNB in
a subframe identical to or different from that in which the grant
has been received.
[0254] The gNB may notify the UE of Ack/Nack in a subframe next to
the subframe in which the UE has received the initial transmission
data, regardless of the next PDCCH reception timing of the UE. The
UE may receive Ack/Nack from the gNB in the next subframe. A
subframe after a predefined number of subframes may be used instead
of the next subframe. The predefined number of subframes may be
defined in a standard, broadcast from the gNB to the UEs being
served thereby, or notified from the gNB to the UE via the
RRC-dedicated signaling.
[0255] The gNB may notify the UE of the grant in a subframe after a
predefined number of subframes with respect to a subframe in which
the gNB has transmitted Ack/Nack to the UE, regardless of the next
PDCCH reception timing. The predefined number of subframes may be a
value of 0, 1, or 2 or more. When the predefined number of
subframes is 0, the gNB may notify the grant in the same subframe
in which the gNB has transmitted Ack/Nack. The predefined number of
subframes may be defined in a standard, broadcast from the gNB to
the UEs being served thereby, or notified from the gNB to the UE
via the RRC-dedicated signaling.
[0256] The UE may transmit the retransmission data to the gNB in a
subframe after a predefined number of subframes with respect to a
subframe in which the gNB has transmitted the grant to the UE,
regardless of the next PDCCH reception timing. The predefined
number of subframes may be a value of 0, 1, or 2 or more. When the
predefined number of subframes is 0, the UE transmits the
retransmission data in the same subframe in which the UE has
received the grant. The predefined number of subframes may be
defined in a standard, broadcast from the gNB to the UEs being
served thereby, or notified from the gNB to the UE via the
RRC-dedicated signaling. The predefined number of subframes is
preferably identical to the number of subframes between the grant
in the initial transmission and the initial transmission data.
[0257] The gNB may include the Ack/Nack information in an uplink
grant for the UE. In other words, the gNB may include Ack/Nack in
response to the reception of the previous uplink signal from the
UE, in a notification of the grant to the UE which will be used for
receiving the next uplink signal. The UE may perform initial
transmission or retransmission of the next user data, using the
Ack/Nack.
[0258] The gNB may not notify the UE of Ack. The UE may regard the
uplink data as being accurately received by the gNB, using the
absence of reception of Ack/Nack in response to the uplink data for
a predefined time. The predefined time may be defined in a
standard, broadcast from the gNB to the UEs being served thereby,
or notified to each of the UEs via the RRC-dedicated signaling. The
gNB may determine the predefined time using a service to be adopted
by the UE. For example, a shorter time may be set to the UE using
the URLLC than that to be set to the UE using the eMBB.
[0259] The method for including Ack/Nack in the uplink grant may be
used in combination with the method for preventing notification of
Ack to the UE. Consequently, the UE can know that the gNB has
successfully received the last piece of uplink user data, without
any need of receiving the grant from the gNB even when finishing
transmitting the consecutive pieces of uplink user data. Since the
gNB need not notify the UE of Ack in response to the last piece of
uplink user data, the communication resources are saved.
[0260] FIG. 11 illustrates transmission/reception channels in the
uplink communication when the notification of Ack/Nack and the
retransmission are performed in a subframe next to the uplink
initial transmission. A portion denoted by a reference 1101 in FIG.
11 represents the downlink control information including a grant to
be notified from the gNB to the UE. Portions denoted by references
1102 and 1104 represent pieces of uplink user data from the UE. A
portion denoted by a reference 1103 represents the downlink control
information including Nack and a grant that are to be notified from
the gNB to the UE. A portion denoted by a reference 1105 represents
the downlink control information including Ack to be notified from
the gNB to the UE.
[0261] FIG. 11 illustrates that the piece of uplink user data in
response to the grant is transmitted in the same subframe as that
for the grant, Ack/Nack in response to the piece of uplink user
data is transmitted in the next subframe, Nack and a grant for
retransmission are transmitted in the same subframe, and the
retransmission is performed in the same subframe as that for
Nack.
[0262] The subframe #2 in FIG. 11 is allocated as the PDCCH
reception timing of the UE. In the subframe #2, the gNB notifies
the UE of the downlink control information 1101 including the
grant. The UE transmits the piece of uplink user data 1102 to the
gNB in the subframe #2 identical to that for the downlink control
information 1101 including the grant.
[0263] In FIG. 11, when the gNB cannot accurately receive the piece
of uplink user data 1102, the gNB allocates the subframe #3 to the
UE, and notifies the UE of the downlink control information 1103
including Nack and the grant for retransmission. The UE receives
the downlink control information 1103 including Nack and the grant
for retransmission in the subframe #3, and obtains Ack/Nack from
the received downlink control information. Upon receipt of the
notification of the Nack from the gNB, the UE transmits the piece
of uplink user data 1104 in the subframe #3.
[0264] In the subframe #4 in FIG. 11, the gNB notifies the UE of
the downlink control information 1105 including Ack. In the
subframe #4, the UE receives the downlink control information 1105
including Ack, and obtains Ack/Nack from the received downlink
control information.
[0265] In the uplink communication according to the first
embodiment, the gNB may allocate the subframe in which Ack is to be
notified to the UE, to the other UEs or to the UE.
[0266] During the allocation to the other UEs, the gNB may
multiplex Ack/Nack for the UE with the downlink control signal for
the other UEs to transmit the resulting signal. The multiplexing
may be time multiplexing using different symbols or frequency
multiplexing in the same symbol. Alternatively, the time
multiplexing may be combined with the frequency multiplexing. In
the time multiplexing, notification of Ack/Nack for the UE may
precede the L1/L2 signaling for the other UEs, or the L1/L2
signaling for the other UEs may precede the Ack/Nack for the UE.
Which one of the signals the gNB determines to notify earlier may
be predefined in a standard. Each of the UE and the other UEs may
receive the signal for its own UE from the gNB based on the
standard.
[0267] The gNB may perform, with the PDCCH reception timing, the
same operations as those in the downlink transmission as operations
for the UE, that is, operations for the UE that are interrupted by
the other UEs with the PDCCH reception timing. In other words, the
gNB may not transmit the L1/L2 signaling to the UE, may notify the
UE of the PDCCH reception timing after the next, or may notify the
UE of the next PDCCH reception timing using a beam sweeping block.
The UE may consecutively perform reception in each subframe,
receive the PDCCH reception timing after the next, or receive the
beam sweeping block.
[0268] According to the first embodiment, the UE may detect a radio
link failure (RLF) when the UE belongs to another beam, another
transmission reception point (TRP), or another cell before the next
PDCCH reception timing. Alternatively, the UE may receive the beam
sweeping block. Upon receipt of the beam sweeping block, the UE may
perform a random access procedure on the gNB using the received
beam.
[0269] The gNB may use the same PDCCH reception timing or different
PDCCH reception timings for a moving source beam and a moving
target beam.
[0270] The gNB may use the same PDCCH reception timing or different
PDCCH reception timings for a moving source TRP and a moving target
TRP. The moving target TRP may request the moving source TRP to
notify the PDCCH reception timing used in the moving source TRP.
The moving target TRP may simultaneously make the request to TRPs
in the gNB. The moving source TRP may notify the moving target TRP
of the PDCCH reception timing.
[0271] The gNB may use the same PDCCH reception timing or different
PDCCH reception timings for a moving source cell and a moving
target cell. The moving target cell may request the moving source
cell to notify the PDCCH reception timing used in the moving source
cell. The request may be made using an interface between the cells.
The moving source cell may notify the moving target cell of the
PDCCH reception timing.
[0272] The methods described in the first embodiment can save the
power consumption and the radio resources that are required for the
UE to receive the downlink control signal in the communication with
the gNB via multi-beams. The prompt retransmission after Nack can
reduce the latency in the communication with the gNB.
[0273] In other words, a base station device (gNB) notifies a
communication terminal device (UE) of information on the next PDCCH
reception timing, according to the first embodiment. The
communication terminal device performs reception based on the
information on the next PDCCH reception timing that has been
notified from the base station device. Consequently, the
communication terminal device can receive the information
transmitted from the base station device with the notified PDCCH
reception timing. Thus, the power consumption and the radio
resources that are required for the reception can be saved. Since
retransmission can be promptly performed when the retransmission is
necessary, the latency in the communication between the base
station device and the communication terminal device can be
reduced. Thus, increase in the power consumption of the
communication terminal device, degradation in the communication
quality, and reduction in the use efficiency of the radio resources
can be suppressed.
[0274] Particularly, the base station device (gNB) and the
communication terminal device (UE) perform transmission and
reception by switching the directivity of a beam emitted from an
antenna, according to the first embodiment. Notification of
information on the next reception timing from the base station
device to the communication terminal device can prevent the
communication terminal device from performing reception when the
beam is directed in a direction different from that for the
communication terminal device. Thus, increase in the power
consumption of the communication terminal device, degradation in
the communication quality, and reduction in the use efficiency of
the radio resources can be suppressed.
[0275] The methods described in the first embodiment may be applied
to a communication system that can switch between beams per symbol.
The methods may also be applied to a communication system that can
communicate simultaneously using a plurality of beams. The methods
may also be applied to a combined communication system of the
aforementioned two communication systems. Switching between beams
per symbol enables the UEs belonging to different beams to be
notified of the PDCCH reception timing in the same subframe, which
can increase the flexibility in the scheduling of the gNB. The
communication simultaneously using a plurality of beams will also
produce the same advantage.
[0276] The methods described in the first embodiment may be applied
to a gNB with a single beam, that is, a gNB that does not perform
beam sweeping. The application of the methods to the gNB with the
single beam can reduce the interference with the other gNB s.
Second Embodiment
[0277] The physical control channel to which uplink control
information (UCI) is to be mapped is the PUCCH in the LTE. The
PUCCH resources are set to each UE. For example, the scheduling
request (SR) configuration such as the PUCCH resources for SR and
the SR period is set to each UE (see 3GPP TS 36.211 V14.0.0
(hereinafter referred to as "Reference 3") and 3GPP TS 36.213
V14.0.0 (hereinafter referred to as "Reference 4"). The RRC
signaling is used in these settings (see 3GPP TS 36.331 V14.0.0
(hereinafter referred to as "Reference 5")).
[0278] Multi-beamforming (MBF) requiring the beam sweeping is being
studied in the NR. The MBF requiring the beam sweeping requires
switching between beams to cover all the coverages. Since one
subframe is solely used for transmitting and receiving one beam,
the subframe cannot be used for transmitting and receiving the
other beams. Thus, the conventional LTE setting method for
configuring PUCCH resources for a plurality of UEs in one subframe
has a problem in that the PUCCH of the UE existing in the beam for
which the coverage is not formed in the subframe cannot be
transmitted and received.
[0279] To solve such a problem, 3GPP proposes providing PUCCH
resources in different symbols for each beam in the operations of
the MBF (see 3GPP R1-1609740 (hereinafter referred to as "Reference
6")). Although 3GPP discloses setting the PUCCH resources to each
symbol, it fails to disclose the setting method. 3GPP fails to
disclose, for example, which symbol is allocated to which beam for
the PUCCH, and how the symbol is allocated for each UE.
[0280] Thus, the UE existing in each beam cannot recognize the
transmission timing and the resources for the PUCCH in the beam
through which its own UE is communicating. When the reception
timing and the resources for the PUCCH in the cell are not aligned
with the transmission timing and the resources for the PUCCH in the
UE via the beam through which the UE is communicating, a problem of
the transmission/reception failure of the PUCCH occurs.
[0281] The second embodiment will disclose a method for solving
such a problem.
[0282] A method for allocating the resources for the PUCCH will be
disclosed. The resources are allocated for the PUCCH for each beam.
Subframes and symbols are allocated as the PUCCH resources for each
beam. The symbols may be allocated using symbol numbers. The symbol
numbers to be set in a subframe may be used. Alternatively, the
maximum number of symbols for the PUCCH resources that are to be
allocated to a subframe may be determined. The symbol numbers may
be renumbered with the maximum number of symbols. Consequently, the
amount of information indicating the symbol numbers, for example,
the number of bits can be reduced.
[0283] The PUCCH resources for each UE are allocated from the PUCCH
resources of the beam in which the UE exists. In other words, the
PUCCH resources for each UE are allocated on the PUCCH resources
for each beam, and multiplexed.
[0284] The PUCCH resources for each UCI for each UE may be
allocated from the PUCCH resources of the beam in which the UE
exists. In other words, the PUCCH resources for each UCI for each
UE may be allocated on the PUCCH resources for each beam, and
multiplexed. In a subframe, a beam for transmitting and receiving a
symbol of a PUCCH resource may be different from a beam for
transmitting and receiving a symbol different from the symbol.
[0285] A method for setting the PUCCH resources for each beam will
be disclosed. A subframe to which the PUCCH for each beam is
allocated is set using a period and an offset, and a symbol to
which the PUCCH is allocated is set using a symbol number.
[0286] FIG. 12 illustrates one example method for setting the PUCCH
resources for each beam using a period, an offset, and a symbol
number. A case where the number of times the beam sweeping is
performed is four will be described herein. The number of times the
beam is switched to cover a predefined coverage is equal to the
number of times the beam sweeping is performed.
[0287] A resource 1201 whose period is 5 subframes, whose offset is
0 subframe, and whose symbol number in the subframes is 10 is set
as a PUCCH resource with a beam number 0. Consequently, the PUCCH
with the beam number 0 is allocated to the resource 1201 whose
period is 5 subframes and whose symbol number in the subframes is
10 (the symbol #10), in subframes whose offset from a reference
subframe number, for example, a subframe with the subframe number 0
is 0. The reference subframe number may be preset. The reference
subframe number may be predetermined in, for example, a
standard.
[0288] Similarly, a resource 1202 whose period is 10 subframes,
whose offset is 1 subframe, and whose symbol number in the
subframes is 11 is set as a PUCCH resource with a beam number 1.
Consequently, the PUCCH with the beam number 1 is allocated to the
resource 1202 whose period is 10 subframes and whose symbol number
in the subframes is 11 (the symbol #11), in subframes whose offset
from a subframe with the reference subframe number is 1.
[0289] Similarly, a resource 1203 whose period is 1 subframe, whose
offset is 0 subframe, and whose symbol number in the subframes is
12 is set as a PUCCH resource with a beam number 2. Consequently,
the PUCCH with the beam number 2 is allocated to the resource 1203
whose period is 1 subframe and whose symbol number in the subframes
is 12 (the symbol #12), in subframes whose offset from the subframe
with the reference subframe number is 0.
[0290] Similarly, a resource 1204 whose period is 2 subframes,
whose offset is 0 subframe, and whose symbol number in the
subframes is 13 is set as a PUCCH resource with a beam number 3.
Consequently, the PUCCH with the beam number 3 is allocated to the
resource 1204 whose period is 2 subframes and whose symbol number
in the subframes is 13 (the symbol #13), in subframes whose offset
from the subframe with the reference subframe number is 0.
[0291] Consequently, the PUCCH resource for each beam is
periodically allocated. When the subframe number is counted per
radio frame and the radio frame number is counted per system frame,
the periodical settings may be renumbered using not only the
subframe number but also the radio frame number and the system
frame number.
[0292] The symbol to which the PUCCH for each beam is allocated may
be set from the end of a subframe. When the DL resources are
provided, the number of gaps can be minimized by allocating, to the
DL, a symbol before the symbol to which the PUCCH is allocated.
[0293] Although the number of symbols to which the PUCCH is
allocated for each beam is one, the number of symbols may be two or
more. With the plurality of symbols, the received power of the
PUCCH by the cell can be increased, and the reception quality of
the PUCCH can be improved. The number of PUCCHs to be multiplexed
in a beam can be increased.
[0294] Although a case where the beam is switched per beam is
described, the beam may be switched per a plurality of beams. When
communication is possible using a plurality of beams with the same
timing, the spatially multiplexing can be performed between the
plurality of beams. Thus, the same resource may be allocated to the
PUCCH per a plurality of beams that enable communication with the
same timing.
[0295] Another method for setting the PUCCH resources for each beam
will be disclosed. The PUCCHs as many as the number of times the
beam sweeping is performed are set within k subframes. Here, k is a
natural number.
[0296] FIG. 13 illustrates one example method for setting the
PUCCHs as many as the number of times the beam sweeping is
performed within k subframes. A case where the number of times the
beam sweeping is performed is four will be described herein. For
example, k=the number of times the beam sweeping is performed. The
PUCCH of each beam is repeatedly allocated to the last symbols
1302, 1304, 1306, and 1308 in the consecutive subframes as many as
the number of times the beam sweeping is performed. Here, the
number of symbols to be allocated to the PUCCH resources is 1
within 1 subframe. The symbol numbers to be allocated to the PUCCH
resources may be fixed.
[0297] Any signal of any beam or a non-transmission section is
allocated to symbols 1301, 1303, 1305, and 1307. Downlink or uplink
may be allocated. For example, a downlink signal with the beam
number 0 is allocated to the symbol 1301. A downlink signal with
the beam number 1 is allocated to the symbol 1303. A downlink
signal with the beam number 2 is allocated to the symbol 1305. A
downlink signal with the beam number 3 is allocated to the symbol
1307.
[0298] The beams from the beam numbers 0 to 3 are swept. The PUCCH
with the beam number 0 is allocated to a subframe number n and a
symbol number 13 (1302). The PUCCH with the beam number 1 is
allocated to a subframe number n+1 and a symbol number 13 (1304).
The PUCCH with the beam number 2 is allocated to a subframe number
n+2 and a symbol number 13 (1306). The PUCCH with the beam number 3
is allocated to a subframe number n+3 and a symbol number 13
(1308). Here, n is an integer larger than or equal to 0.
[0299] The PUCCH of each beam is repeatedly allocated to the last
symbols 1302, 1304, 1306, and 1308 for each of subframes as many as
the number of times the beam sweeping is performed. When the
subframe number is counted per radio frame and the radio frame
number is counted per system frame, the PUCCHs may be renumbered to
be repeatedly allocated using not only the subframe number but also
the radio frame number and the system frame number.
[0300] Consequently, the PUCCHs of all beams can be allocated to
the subframes as many as the number of times the beam sweeping is
performed. Thus, the PUCCH of each beam can be transmitted and
received at least once in the subframes as many as the number of
times the beam sweeping is performed.
[0301] FIG. 14 illustrates another example method for setting the
PUCCHs as many as the number of times the beam sweeping is
performed within k subframes. A case where the number of times the
beam sweeping is performed is four will be described herein. For
example, k=1. The PUCCHs of all beams are allocated to one
subframe, and are repeatedly allocated per subframe (1402 to 1405,
1407 to 1410, 1412 to 1415, and 1417 to 1420). In other words, the
PUCCHs are repeatedly allocated to each subframe. The number of
symbols to be allocated to the PUCCH resource for each beam is 1
within 1 subframe. The symbol numbers to be allocated to the PUCCH
resources may be fixed. The symbols as many as the number of times
the beam sweeping is performed are allocated from the end of one
subframe.
[0302] Any signal of any beam or a non-transmission section is
allocated to symbols 1401, 1406, 1411, and 1416. Downlink or uplink
may be allocated. For example, a downlink signal with the beam
number 0 is allocated to the symbol 1401. A downlink signal with
the beam number 1 is allocated to the symbol 1406. A downlink
signal with the beam number 2 is allocated to the symbol 1411. A
downlink signal with the beam number 3 is allocated to the symbol
1416.
[0303] The beams from the beam numbers 0 to 3 are swept. The PUCCH
with the beam number 0 is allocated to a subframe number n and a
symbol number 10 (1402, 1407, 1412, and 1417). The PUCCH with the
beam number 1 is allocated to the subframe number n and a symbol
number 11 (1403, 1408, 1413, and 1418). The PUCCH with the beam
number 2 is allocated to the subframe number n and a symbol number
12 (1404, 1409, 1414, and 1419). The PUCCH with the beam number 3
is allocated to the subframe number n and a symbol number 13 (1405,
1410, 1415, and 1420). Here, n is an integer larger than or equal
to 0.
[0304] Consequently, the PUCCH resources for all beams are
allocated to different symbols in the same subframe. Consequently,
the PUCCHs of all beams can be included in each subframe. For
example, the SR period of the SR to be transmitted with the PUCCH
can be set per subframe. Specifically, when the subframe is 1 ms
long, the SR period can be set to 1 ms. Since this can shorten the
time from when the UE has data to be transmitted to transmission of
the SR, the latency until start of transmission of the data can be
shortened.
[0305] FIG. 15 illustrates another example method for setting the
PUCCHs as many as the number of times the beam sweeping is
performed within k subframes. The PUCCH resources corresponding to
the number of times the beam sweeping is performed are individually
allocated to subframes and symbols in the k subframes per k
subframes. This allocation pattern for the k subframes is repeated.
A case where the number of times the beam sweeping is performed is
four will be described herein. For example, k=4.
[0306] Any signal of any beam or a non-transmission section is
allocated to symbols 1501, 1503, 1505, and 1508. Downlink or uplink
may be allocated. For example, a downlink signal with the beam
number 0 is allocated to the symbol 1501. A downlink signal with
the beam number 1 is allocated to the symbol 1503. A downlink
signal with the beam number 2 is allocated to the symbol 1505. A
downlink signal with the beam number 3 is allocated to the symbol
1508.
[0307] The beams from the beam numbers 0 to 3 are swept. The PUCCH
with the beam number 0 is allocated to a subframe number n and a
symbol number 13 (1502). The PUCCH with the beam number 1 is
allocated to a subframe number n+1 and a symbol number 13 (1504).
The PUCCH with the beam number 2 is allocated to a subframe number
n+2 and a symbol number 12 (1506). The PUCCH with the beam number 3
is allocated to a subframe number n+2 and a symbol number 13
(1507). The PUCCH is not allocated to a subframe number n+3. Here,
n is an integer larger than or equal to 0.
[0308] Consequently, the PUCCHs of all beams are allocated within
the k subframes. Increasing or decreasing k can change the number
of times the PUCCH resources are allocated. Thus, the amount of
resources to which the PUCCH is allocated can be flexibly set
according to a load of the cell and a type of a service to be
adopted by the UE.
[0309] Although the number of symbols to which the PUCCH of one
beam is allocated in the k subframes to be repeated is one, the
number of symbols is not limited to one but may be two or more. The
number of symbols may differ for each beam. Making, different for
each beam, the number of symbols to which the PUCCH of one beam in
the k subframes to be repeated is allocated enables a flexible
setting for the PUCCH resources.
[0310] The aforementioned example discloses the repeated and
consecutive allocation of the k subframes. As an alternative
method, the k subframes may be allocated not consecutively but
discretely or periodically. For example, the k subframes to which
the PUCCH is allocated may be periodically repeated at m subframe
intervals. In other words, the k subframes to which the PUCCH is
allocated may be periodically repeated per m+1 subframes. Here, m
is an integer larger than or equal to 0.
[0311] Consequently, a subframe to which the PUCCH resources are
not set can be provided between subframes to which the PUCCH
resources are set. For example, subframes solely dedicated to the
DL can be set. This enables a more flexible setting for the PUCCH
resources. The amount of communication latency of the DL and the
UL, and the amount of communication can be flexibly set.
[0312] The cell may increase or decrease the PUCCH resources
according to the number of UEs existing in a beam. For example, the
cell may increase or decrease the PUCCH resources on the time axis,
according to the latency requested by the UEs existing in a
beam.
[0313] For example, setting k and m larger in a method for setting
and repeatedly allocating the PUCCHs as many as the number of times
the beam sweeping is performed within the k subframes reduces the
number of times the PUCCH resources are allocated, and increases
the amount of resources to be allocated to the other data and the
control information. Conversely, setting k and m smaller increases
the number of times the PUCCH resources are allocated, and reduces
the latency until start of the transmission.
[0314] The beams via which communication is performed in each of j
subframes to be repeated may be determined. Here, j is a natural
number. The disclosed methods may be applied to a method for
setting the PUCCH in such a case. The methods may be applied to
uplink subframes. k=j may be set. The disclosed methods may be
applied for setting the PUCCH resources to the beams via which
communication is performed, in the subframes that have been set to
the beams.
[0315] A method for determining allocation of the PUCCH resources
will be disclosed. The cell sets the PUCCH resources for each beam.
The following (1) to (7) will be disclosed as examples of the
judgment indicator.
[0316] (1) a load of each beam
[0317] For example, the PUCCH resources are more frequently
allocated when the load of each beam is high, whereas the PUCCH
resources are less frequently allocated when the load of each beam
is low.
[0318] (2) the number of UEs existing in each beam
[0319] For example, the PUCCH resources are more frequently
allocated when the number of UEs existing in each beam is many,
whereas the PUCCH resources are less frequently allocated when the
number of UEs existing in each beam is few.
[0320] (3) the use service of UEs existing in each beam
[0321] For example, the PUCCH resources are more frequently
allocated in the presence of a UE with a service through which the
uplink data is more frequently generated, whereas the PUCCH
resources are less frequently allocated in the presence of a UE
with a service through which the uplink data is less frequently
generated. The PUCCH resources may be allocated according to a UE
with a service through which the uplink data is the most frequently
generated among the UEs existing in the beam.
[0322] (4) the requested QoS of a service of the UEs being served
by each beam
[0323] For example, the PUCCH resources are more frequently
allocated in the presence of a UE with a service requiring high
QoS, whereas the PUCCH resources are less frequently allocated in
the presence of a UE with a service requiring low QoS. The PUCCH
resources may be allocated according to a UE with the highest
requested QoS among the UEs existing in the beam.
[0324] (5) the latency requested by the UEs existing in each
beam
[0325] For example, the PUCCH resources are less frequently
allocated in the presence of a UE with a service requiring high
latency, whereas the PUCCH resources are more frequently allocated
in the presence of a UE with a service requiring low latency. The
PUCCH resources may be allocated according to a UE with the lowest
requested latency among the UEs existing in the beam.
[0326] (6) the requested throughput of UEs existing in each
beam
[0327] For example, the PUCCH resources are more frequently
allocated in the presence of a UE with a service requiring high
throughput, whereas the PUCCH resources are less frequently
allocated in the presence of a UE with a service requiring low
throughput. The PUCCH resources may be allocated according to a UE
with the highest requested throughput among the UEs existing in the
beam.
[0328] (7) combinations of (1) to (6) above
[0329] A method for setting the PUCCH resources to the UE will be
disclosed.
[0330] The cell notifies the UE of information on the PUCCH
resources. The following (1) to (13) will be disclosed as examples
of the information on the PUCCH resources.
[0331] (1) a beam ID
[0332] The beam ID in (1) indicates of which beam the setting of
the PUCCH is.
[0333] (2) a period
[0334] The period in (2) indicates a period with which the PUCCH is
allocated. The period may be set, for example, per radio frame, per
subframe, or per symbol.
[0335] (3) an offset
[0336] The offset in (3) indicates an offset to which the PUCCH is
allocated. The offset may be set, for example, per radio frame, per
subframe, or per symbol.
[0337] (4) a symbol number
[0338] The symbol number in (4) indicates to which symbol the PUCCH
is allocated.
[0339] (5) a subframe number
[0340] The subframe number in (5) indicates to which subframe the
PUCCH is allocated.
[0341] (6) k
[0342] The k in (6) indicates per how many subframes the PUCCH
resources for each beam are allocated.
[0343] (7) m
[0344] The m in (7) indicates per how many subframes the PUCCH for
each beam is repeatedly allocated.
[0345] (8) a type of UCI
[0346] The type of UCI in (8) indicates of which UCI of the PUCCH
is allocated.
[0347] (9) frequency resources
[0348] The frequency resources in (9) indicate to which frequency
resources the PUCCH is allocated.
[0349] (10) Cyclic Shift (CS)
[0350] The CS in (10) indicates the CS of the ZC sequence to be
used for the PUCCH.
[0351] (11) a sequence number
[0352] The sequence number in (11) indicates the sequence number of
a sequence to be used for the PUCCH.
[0353] (12) an orthogonal code
[0354] The orthogonal code in (12) indicates the orthogonal code if
the orthogonal code is used for the PUCCH.
[0355] (13) combinations of (1) to (12) above
[0356] The information on the PUCCH resources may include
information on the RS for the PUCCH. The cell notifies the
information on the PUCCH resources via a beam via which the UE can
communicate. The beam via which the UE can communicate will be
referred to as a "serving beam". The information on the PUCCH
resources may not always be fixed. The cell may notify the UE of
the information semi-statically or dynamically set.
[0357] The UE obtains the information on the PUCCH resources
through notification of such information. Consequently, the UE can
recognize the setting of the PUCCH resources of its own UE.
[0358] The cell may notify the UE of the information on the PUCCH
resources via a single beam covering the entire coverage of the
cell.
[0359] The information on the PUCCH resources for each beam and the
information on the PUCCH resources for each UE may be provided. The
information on the PUCCH resources for each beam and the
information on the PUCCH resources for each UE may be provided in
combination. The cell may notify the UE of the information on the
PUCCH resources for each beam and the information on the PUCCH
resources for each UE separately. Upon obtainment of these pieces
of information, the UE can recognize the setting of the PUCCH
resources of its own UE.
[0360] An example method for setting the PUCCH resources for each
beam when a subframe to which the PUCCH for each beam is allocated
is set using a period and an offset, and a symbol to which the
PUCCH is allocated is set using a symbol number will be
described.
[0361] Examples of the information on the PUCCH resources for each
beam include (1) a beam ID, (2) a period, (3) an offset, (4) a
symbol number, (10) the CS, and (11) a route sequence number. The
cell notifies the UE of the information on the PUCCH resources for
each beam. The cell may notify the information on the PUCCH
resources for each beam of all the beams formed by the cell.
Consequently, the UE can recognize of which symbol in which
subframe the PUCCH resources are set for each beam. The UE can also
recognize the CS and a route sequence to be used for the PUCCH.
[0362] Examples of the information on the PUCCH resources for each
UE include (2) a period, (3) an offset, (8) a type of UCI, and (9)
frequency resources. The cell notifies the UE of the information on
the PUCCH resources for each UE. Consequently, the UE can recognize
to which frequency resource of which symbol in which subframe the
PUCCH resources are set according to the type of the UCI of its own
UE.
[0363] The cell sets, to the UE, the PUCCH resources for each UE
from among the PUCCH resources to be set to each beam of the beams
in which the UE exists. The cell notifies the UE of information on
the set PUCCH resources for each UE.
[0364] A part or the entirety of the information on the PUCCH
resources for each beam may be identical to that for each UE. In
such a case, the cell may notify the UE of the information on the
PUCCH resources with the same setting once. The same setting may be
eliminated from the information on the PUCCH resources for each
beam. The cell has only to notify the information on the PUCCH
resources for each UE.
[0365] A method for notifying the information on the PUCCH
resources for each beam will be disclosed.
[0366] The cell sets, to each cell, the PUCCH resources for each
beam. The cell notifies the UE of information on the PUCCH
resources for each beam that has been set to each cell, as
information on the cell. The cell notifies the UEs being served by
the cell of the information on the PUCCH resources for each beam.
The information on the PUCCH resources for each beam includes
information on the PUCCH resources for each beam of the beams via
which the UE is communicating.
[0367] The cell may notify the UE of information on the PUCCH
resources for each beam of all the beams in the cell.
Alternatively, the cell may notify information on the PUCCH
resources for each beam of not all the beams in the cell but a
plurality of beams. The cell may notify, for example, information
on the PUCCH resources for a beam via which the UE is
communicating, and information on the PUCCH resources for a
plurality of beams having the surrounding coverage. This saves
notification of information on the PUCCH resources for each moving
target beam when the UE moves between beams.
[0368] Alternatively, the cell may notify the UE of information on
the PUCCH resources for each beam of only the beams via which the
UE is communicating. This can reduce the amount of information per
signaling. Alternatively, the cell may notify information on the
PUCCH resources for each beam of one or more beams determined by
the cell. The cell may notify, for example, information on the
PUCCH resources for each beam of the beams whose setting has been
changed. Each time the setting is changed, the cell need not notify
information on the PUCCH resources for each beam of all the beams.
The cell may notify only information on the changed setting in the
information on the PUCCH resources for each beam. This can further
reduce the amount of information to be notified.
[0369] The cell notifies the UE of the information on the PUCCH
resources for each beam via a serving beam. When the cell notifies
the information via the serving beam, the beam ID may be eliminated
from information on the PUCCH resources for the serving beam. When
the cell notifies information on the PUCCH resources for a beam
different from the serving beam, the beam ID may be included in the
information on the PUCCH resources. Consequently, the UE can obtain
the information on the PUCCH resources for each beam via the beam
via which the UE is communicating.
[0370] As an alternative method, the cell may notify the
information on the PUCCH resources via a single beam covering the
entire coverage of the cell. Since the cell can notify the entire
coverage of the cell of the information on the PUCCH resources, the
signaling load can be reduced.
[0371] The cell may include the information on the PUCCH resources
in the system information to notify the information. The cell may
broadcast the information on the PUCCH resources. Alternatively,
the cell may notify the information on the PUCCH resources via the
UE-dedicated signaling. The notification via the UE-dedicated
signaling will not increase the amount of information to be
broadcast by the cell. Thus, increase in the radio resources
required for the broadcasting can be suppressed. The notification
via the UE-dedicated signaling enables notification using the
resources for each beam. Consequently, the cell can flexibly notify
the information on the PUCCH resources for each beam.
[0372] A method for notifying the information on the PUCCH
resources for each UE will be disclosed.
[0373] The cell notifies the UE of the information on the PUCCH
resources as information dedicated to the UE. The cell may notify a
part or the entirety of the information on the PUCCH resources for
each beam. For example, when a part of the setting of the
information on the PUCCH resources dedicated to the UE is changed,
the cell may notify the UE of only the part of the information.
This can reduce the amount of information to be notified.
[0374] The cell notifies the information on the PUCCH resources via
the serving beam. When the cell notifies the information via the
serving beam, the beam ID may be eliminated. The cell may notify
the information on the PUCCH resources via the UE-dedicated
signaling. Consequently, the UE can obtain the information on the
PUCCH resources for each UE via the beam via which the UE is
communicating.
[0375] As an alternative method, the cell may notify the
information on the PUCCH resources via a single beam covering the
entire coverage of the cell. Since the cell can notify the entire
coverage of the cell of the information on the PUCCH resources, the
signaling load can be reduced.
[0376] Alternatively, the cell may notify the UE of information on
the PUCCH resources for each UCI for each UE. The notification
methods previously described may be applied thereto. The cell can
set the PUCCH resources for each UCI, and the UE can transmit the
PUCCH for each UCI with the setting of the PUCCH resources set for
each UCI.
[0377] A setting may be made so that a plurality of UEs perform the
frequency-division multiplexing or the code-division multiplexing
as a method for setting the PUCCHs of the plurality of UEs to one
symbol that is a PUCCH resource for each beam.
[0378] FIG. 16 illustrates one example sequence for setting the
PUCCHs and transmitting and receiving the SR. FIG. 16 illustrates a
case where the cell notifies the UE of the information on the PUCCH
resources for each beam and the information on the PUCCH resources
for each UE separately.
[0379] In Step ST2501, the cell sets a PUCCH resource configuration
for each beam of all the beams in the cell.
[0380] In Step ST2502, the cell notifies the UE of information on
the PUCCH resources for each beam which includes information on the
PUCCH resources for each beam of the beams via which the UE
communicates. The cell may make the notification via a beam via
which the cell communicates with the UE. The cell notifies the
information via the RRC-dedicated signaling.
[0381] Upon receipt of the information on the PUCCH resources for
each beam in Step ST2502, the UE stores, in Step ST2503, the PUCCH
resource configuration corresponding to the serving beam that is a
beam via which the UE communicates. Here, the UE may store the
information on the PUCCH resources for each beam of all the beams
notified.
[0382] In Step ST2504, the cell sets a PUCCH resource configuration
for each UE.
[0383] In Step ST2505, the cell notifies the UE of the information
on the PUCCH resources for each UE. The cell notifies the
information via the RRC-dedicated signaling.
[0384] Upon receipt of the information on the PUCCH resources for
each UE in Step ST2505, the UE sets the PUCCH resource
configuration for each UE on the PUCCH resources for each beam in
Step ST2506. Specifically, the UE sets the PUCCH resource
configuration of its own UE, using the information on the PUCCH
resources for each beam and the information on the PUCCH resources
for each UE in Step ST2506.
[0385] Upon notification of the information on the PUCCH resources
for each UE in Step ST2505, the cell starts, in Step ST2507,
reception with the PUCCH resource configuration for each UE that
has been set to the UE.
[0386] In Step ST2508, the UE determines whether the uplink data
has been generated. When determining in Step ST2508 that the uplink
data is not generated, the UE returns to Step ST2508 to repeat the
determination on whether the uplink data has been generated. When
determining in Step ST2508 that the uplink data has been generated,
the UE proceeds to Step ST2509.
[0387] In Step ST2509, the UE transmits the SR to the cell via the
serving beam with the PUCCH resources for the SR that have been set
for each UE.
[0388] The cell, which has started reception in Step ST2507 with
the PUCCH resources for each UE that have been set to the UE,
receives the SR transmitted from the UE in Step ST2509.
[0389] In Step ST2510, the cell starts uplink scheduling for the UE
according to the received SR.
[0390] In Step ST2511, the cell transmits, to the UE, an uplink
grant, specifically, the uplink scheduling information including
the uplink grant.
[0391] Upon receipt of the uplink grant in Step ST2511, the UE
transmits a Buffer Status Report (BSR) to the cell using the uplink
grant in Step ST2512. Here, the UE may transmit the uplink
data.
[0392] Upon receipt of the BSR in Step ST2512, the cell performs
the uplink scheduling for the UE according to the BSR.
[0393] In Step ST2513, the cell transmits the uplink grant to the
UE. Upon receipt of the uplink grant in Step ST2513, the UE
transmits the uplink data to the cell using the uplink grant in
Step ST2514. In Step ST2514, the cell receives the uplink data
transmitted from the UE.
[0394] Consequently, the uplink communication is started between
the UE and the cell.
[0395] Although the UE transmits the BSR to the cell in Step
ST2512, the UE may transmit the uplink data together with the BSR.
Alternatively, the UE may transmit only the uplink data. If the
uplink data has a small amount of data, transmission of the uplink
data can be completed by its mere transmission. Moreover, the
latency can be shortened.
[0396] Although disclosed is notification of the information on the
PUCCH resources for each beam from the cell to the UE, the
information on the PUCCH resources for each beam may be statically
predetermined in, for example, a standard. Alternatively, a
function for outputting information on the PUCCH resources for each
beam such as a subframe number and a symbol number may be used,
using a beam ID as an input parameter. Consequently, the signaling
load between the cell and the UE can be reduced.
[0397] Application of the methods disclosed in the second
embodiment enables setting of the PUCCH resources when the beam
sweeping in the MBF comes into operation.
[0398] The cell sets the PUCCH resources to the UE according to the
methods disclosed in the second embodiment, which enables
transmission and reception of the PUCCH via the beam via which the
UE is communicating, and enables the uplink communication from the
UE to the cell.
[0399] What is disclosed is that in a subframe, a beam for
transmitting and receiving a symbol of a PUCCH resource may be made
different from a beam for transmitting and receiving a symbol
different from the symbol. A gap may not be provided in a subframe
where a PUCCH of a beam different from the beam for transmitting
and receiving another symbol is configured, even when the other
symbol is used for downlink communication.
[0400] Since the beams differ between downlink and uplink, the UE
does not consecutively perform reception of the downlink signal and
transmission of the uplink signal. Thus, the gap is unnecessary
because there is no overlap between the reception and the
transmission in the UE.
[0401] The cell may set the gap configuration and notify it to the
UE. The cell may include the gap setting in the information on the
PUCCH resources. The cell may notify the UE of the gap setting
together with information on the other PUCCH resources.
[0402] The cell sets the gap configuration and is ready to notify
the UE of the gap configuration, which enables, for example,
setting of no gap between downlink and uplink when different beams
are used between a symbol for the downlink and a symbol for the
uplink in one subframe.
[0403] Consequently, a gap conventionally required can be used for
downlink communication or uplink communication. This can increase
the use efficiency of the radio resources.
[0404] It takes some time for a transceiver to switch between beams
when the beams are switched for each symbol. The transceiver may
not be able to perform normal transmission and reception during the
duration. Thus, the setting for a beam switching duration is
necessary. The beam switching duration may be statically determined
in, for example, a standard. The cell and the UE can recognize a
duration during which neither transmission nor reception is
possible. The beam switching duration may be determined to fall
within the CP length. The beams can be switched without influencing
data to be transmitted in one symbol.
First Modification of Second Embodiment
[0405] The first modification will disclose another method for
solving the problems disclosed in the second embodiment. The second
embodiment discloses predetermining the PUCCH resources for each
beam, and setting the PUCCH resources for each UE out of the PUCCH
resources for each beam. Since a required setting period of the
PUCCH differs depending on a service through which communication is
performed for each UE, some of the PUCCH resources set for each
beam are not used. This creates a problem of reduction in the use
efficiency of the radio resources.
[0406] The first modification will disclose a method for solving
such a problem.
[0407] The PUCCH resources are set for each UE. Not the PUCCH
resources for each beam but the PUCCH resources for each UE are
set. The PUCCH resources may be dynamically set. Dynamically
setting the PUCCH resources for each UE enables the PUCCH resources
to be timely set according to a connected state of the UE. It is
also possible to suppress reduction in the use efficiency of the
resources due to non-use of some of the PUCCH resources that are
set for each beam according to the methods disclosed in the second
embodiment.
[0408] A method for setting the PUCCH resources to the UE will be
disclosed.
[0409] The cell notifies the UE of information on the PUCCH
resources to be set for each UE, and sets the PUCCH resources to
the UE. What is disclosed in the second embodiment may be applied
as examples of the information on the PUCCH resources. A setting
example according to the first modification will be disclosed. A
subframe to which the PUCCH for each UE is allocated is set using a
period and an offset, and a symbol to which the PUCCH is allocated
is set using a symbol number.
[0410] A subframe period may be of one or more predefined values. A
combination between a subframe period and an offset may be indexed,
and the subframe period may be set using the index. The symbols may
be allocated using symbol numbers. Alternatively, the symbols may
be allocated using symbol numbers to be set within a subframe. For
example, the subframe period is set to 10, the offset is set to 4,
and the symbol number is set to 13. Here, the PUCCH is allocated to
a symbol whose symbol number is 13 at 10 subframe intervals from
the fifth subframe.
[0411] The maximum number of symbols for the PUCCH resources that
are to be allocated to a subframe may be determined. The symbol
numbers may be renumbered and set with the maximum number of
symbols. Consequently, the amount of information indicating the
symbol numbers, for example, the number of bits can be reduced.
[0412] The cell sets, to the UE, the frequency resources for the
PUCCHs, the CS, and the sequence number. The UE configures,
according to these pieces of information, the PUCCH in a symbol
with the timing with which the PUCCH is allocated.
[0413] When the cell sets, to UEs whose serving beams are
different, the PUCCH resources for each of the UEs, the cell makes
the settings to prevent the timings with which the PUCCH resources
are set to these UEs from coinciding with each other. When the cell
allocates symbols to the PUCCH resources, the cell may make the
setting to prevent the PUCCH resources from being allocated to the
same symbol in the same subframe.
[0414] The cell notifies the information via the serving beam. When
the cell notifies the information via the serving beam, the beam ID
may be eliminated. The cell may notify the information via the
UE-dedicated signaling. Consequently, the UE can obtain the
information on the PUCCH resources for each UE via the beam via
which the UE is communicating.
[0415] The UE-dedicated signaling may be the RRC signaling. The
information on the PUCCH resources for each UE may be included in
an RRC message. Alternatively, the UE-dedicated signaling may be
the L1/L2 control signaling. The information on the PUCCH resources
for each UE may be included in the downlink L1/L2 control
information (may be downlink control information). Since the UE can
receive the setting relatively earlier via the L1/L2 control
signaling as the UE-dedicated signaling, the setting latency can be
reduced.
[0416] Alternatively, the UE-dedicated signaling may be the MAC
signaling. The information on the PUCCH resources for each UE may
be included in the MAC control information. Since the HARQ is
applied when the MAC signaling is used as the UE-dedicated
signaling, the UE can perform reception at a low reception error
rate, and receive the setting relatively earlier.
[0417] FIG. 17 illustrates one example sequence for setting the
PUCCHs for each UE and transmitting and receiving the SR. Since the
sequence illustrated in FIG. 17 includes the same Steps as those in
the sequence illustrated in FIG. 16, the same step numbers will be
assigned to the same Steps and the common description thereof will
be omitted. FIG. 17 illustrates a case where the cell notifies the
UE of the information on the PUCCH resources to be set for each
UE.
[0418] In Step ST2601, the cell sets, to the UE, a PUCCH resource
configuration for each UE. The cell sets, to the UE, even a symbol
number to which the PUCCH is allocated. Here, the cell makes the
settings for the UEs whose serving beams are different to prevent
the PUCCH resource timings from coinciding with each other.
[0419] In Step ST2602, the cell notifies the UE of the information
on the PUCCH resources for each UE. The cell includes the symbol
number (symbol #) to which the PUCCH is allocated in the
information on the PUCCH resources. The cell may make the
notification via a beam via which the cell communicates with the
UE. The cell notifies the information via the RRC-dedicated
signaling.
[0420] Upon receipt of the information on the PUCCH resources for
each UE in Step ST2602, the UE sets the PUCCH resource
configuration in Step ST2603.
[0421] Upon notification of the information on the PUCCH resources
to the UE in Step ST2602, the cell starts reception in Step ST2604
with the PUCCH resource configuration that is set to the UE.
[0422] In Step ST2605, the UE determines whether the uplink data
has been generated. When the uplink data is not generated in Step
ST2605, the UE returns to Step ST2605 to repeat the determination
on whether the uplink data has been generated. When the uplink data
has been generated in Step ST2605, the UE proceeds to Step
ST2606.
[0423] In Step ST2606, the UE transmits the SR to the cell via the
serving beam with the set PUCCH resources for the SR.
[0424] The cell, which has started reception in Step ST2604 with
the PUCCH resources that have been set to the UE, receives the SR
transmitted from the UE in Step ST2606.
[0425] Upon receipt of the SR from the UE, the cell performs a
process for starting the uplink communication. Consequently, the
uplink communication is started between the UE and the cell.
[0426] Application of the methods disclosed in the first
modification enables setting of the PUCCH resources when the beam
sweeping in the MBF comes into operation. The cell sets the PUCCH
resources to the UE according to the methods disclosed in the first
modification, which enables transmission and reception of the PUCCH
via the beam via which the UE is communicating, and enables the
uplink communication from the UE to the cell.
[0427] Dynamically setting the PUCCH resources for each UE enables
the PUCCH resources to be set according to a connected state of the
UE. It is also possible to suppress reduction in the use efficiency
of the resources due to non-use of some of the PUCCH resources that
are set for each beam according to the methods disclosed in the
second embodiment.
[0428] Although disclosed is notification of the information on the
PUCCH resources from the cell via the serving beam, the cell may
notify the information via a single beam covering the entire
coverage of the cell as an alternative method. Since the cell can
notify the entire coverage of the cell of the information on the
PUCCH resources, the signaling load can be reduced.
[0429] Alternatively, the cell may notify the UE of information on
the PUCCH resources for each UCI for each UE. The notification
methods previously described may be applied thereto. The cell can
set the PUCCH resources for each UCI, and the UE can transmit the
PUCCH for each UCI with the setting of the PUCCH resources set for
each UCI.
[0430] Another setting example according to the first modification
will be disclosed. Information on starting, modifying, and stopping
the setting of the PUCCH resources is set to each UE. The cell
notifies the UE of the information on the PUCCH resources for each
UE in advance. The cell sets the PUCCH resources to the UE by
notifying the UE of the information on starting, modifying, and
stopping the setting of the PUCCH resources. Upon receipt of the
settings, the UE actually transmits the PUCCH, transmits the PUCCH
after being modified, or stops the PUCCH.
[0431] The following (1) to (8) will be described as examples of
the information on starting, modifying, and stopping the setting of
the PUCCH resources:
[0432] (1) information indicating start;
[0433] (2) information indicating stop;
[0434] (3) information indicating modification;
[0435] (4) information indicating a setting duration;
[0436] (5) information indicating a stop duration;
[0437] (6) information indicating an offset;
[0438] (7) a symbol number: and
[0439] (8) combinations of (1) to (7) above.
[0440] (1) indicates the information indicating start. When the
information is set to the UE, the UE can transmit the PUCCH with
the preset PUCCH resources.
[0441] (2) indicates the information indicating stop. When the
information is set to the UE, the UE stops transmitting the PUCCH
with the preset PUCCH resources.
[0442] (3) indicates the information indicating modification. When
the information is set to the UE, the UE can transmit the PUCCH
with resources whose settings have been modified from the PUCCH
resources. The UE may also notify the PUCCH resource information to
be modified.
[0443] (4) indicates the information indicating a setting duration.
When the information is set to the UE, the UE can transmit the
PUCCH with the PUCCH resources for the setting duration since start
of the setting. The setting may be stopped when the setting
duration expires.
[0444] (5) indicates the information indicating a stop duration.
When the information is set to the UE, the UE stops transmitting
the PUCCH with the PUCCH resources for the stop duration since stop
of the setting. The setting may be started when the stop duration
expires.
[0445] (6) indicates the information indicating an offset. When the
information is set to the UE, the UE starts the setting by
offsetting the offset value from the timing of, for example, start
of the setting.
[0446] (7) indicates a symbol number to which the PUCCH is
allocated. When the information is set to the UE, the UE sets the
PUCCH resources to the symbol number. When the PUCCH resources to
be preset to the UE include a symbol number, the UE follows a newly
set symbol number.
[0447] FIG. 18 illustrates one example method for setting the
information on starting, modifying, and stopping the setting of the
PUCCH resources to each UE. A case where the number of times the
beam sweeping is performed is four will be described herein. In
FIG. 18, the horizontal axis represents subframes, and the vertical
axis represents symbol numbers in the subframes. FIG. 18
illustrates a case where the number of symbols to which the PUCCHs
are allocated is four per subframe at the maximum. Here, the symbol
numbers in the subframe are renumbered from 0 to 3.
[0448] Here, the symbol number 10 corresponds to the symbol number
0, the symbol number 11 corresponds to the symbol number 1, the
symbol number 12 corresponds to the symbol number 2, and the symbol
number 13 corresponds to the symbol number 3. The cell may notify,
in advance, the UE of the maximum number of symbols to which the
PUCCH is allocated per subframe, and associations between the
symbol numbers and the renumbered symbol numbers in the subframe.
Such information may be included in the information on the PUCCH
resources for each UE to be notified in advance. The UE can
recognize the symbol numbers to which the PUCCHs are allocated,
using such information.
[0449] In FIG. 18, arrows represent information to be notified from
the cell to the UE. The cell notifies, in advance, the UEs 1 to 4
of information on the PUCCH resources for each of the UEs. When
determining to start the setting of the PUCCH resource to the UE 2,
the cell notifies the UE 2 of information indicating start of the
PUCCH setting together with the symbol number to which the PUCCH is
allocated (Str_UE#2 (symbol #3)). Here, the symbol number is 3.
Consequently, the PUCCH resource is set to the UE 2.
[0450] When determining to start the setting of the PUCCH resource
to the UE 3, the cell notifies the UE 3 of information indicating
start of the PUCCH setting together with the symbol number to which
the PUCCH is allocated (Str_UE#3 (symbol #2)). Here, the symbol
number is 2. Consequently, the PUCCH resource is set to the UE
3.
[0451] When determining to start the setting of the PUCCH resource
to the UE 1, the cell notifies the UE 1 of information indicating
start of the PUCCH setting together with the symbol number to which
the PUCCH is allocated (Str_UE#1 (symbol #3)). Here, the symbol
number is 3. Consequently, the PUCCH resource is set to the UE
1.
[0452] When determining that the PUCCH resource set to the UE 2
conflicts with the PUCCH resource set to the UE 1, the cell
determines to modify the setting of the PUCCH resources, and
notifies it to the UE. Here, the cell notifies the UE 2 of
information indicating modification of the setting of the PUCCH
resource together with the symbol number to be allocated after the
modification (Mod_UE#2 (symbol #2)). Here, the symbol number is 2.
Consequently, the setting of the PUCCH resource is modified for the
UE 2.
[0453] When determining that the PUCCH resource set to the UE 3
conflicts with the PUCCH resource set to the UE 2, the cell
determines to modify the setting of the PUCCH resources, and
notifies it to the UE. Here, the cell notifies the UE 3 of
information indicating modification of the setting of the PUCCH
resource together with the symbol number to be allocated after the
modification (Mod_UE#3 (symbol #1)) Here, the symbol number is 1.
Consequently, the setting of the PUCCH resources is modified for
the UE 3.
[0454] When determining to start the setting of the PUCCH resources
for the UE 4, the cell notifies the UE 4 of information indicating
start of the PUCCH setting together with the symbol number to which
the PUCCH is allocated (Str_UE#4 (symbol #2)). Here, the symbol
number is 2. Consequently, the PUCCH resources are set to the UE
4.
[0455] When determining to stop the setting of the PUCCH resource
to the UE 2, the cell notifies the UE 2 of information indicating
stop of the PUCCH setting (Stp_UE#2). Consequently, the PUCCH
resources set to the UE 2 are released.
[0456] Since the PUCCH resources set to the UE 2 are released, the
cell determines that the PUCCH resources set to the UE 2 do not
conflict with the PUCCH resources set to the UE 3. Then, the cell
determines to modify the setting of the PUCCH resources, and
notifies it to the UE 3. Here, the cell notifies the UE 3 of
information indicating modification of the setting of the PUCCH
resources together with the symbol number to be allocated after the
modification (Mod_UE#3 (symbol #2)). Here, the symbol number is 2.
Consequently, the setting of the PUCCH resources is modified for
the UE 3.
[0457] When determining to stop the setting of the PUCCH resources
for the UE 1, the cell notifies the UE 1 of information indicating
stop of the PUCCH setting (Stp_UE#1). Consequently, the PUCCH
resources set to the UE 1 are released.
[0458] Since the PUCCH resources set to the UE 1 are released, the
cell determines that the PUCCH resources set to the UE 1 do not
conflict with the PUCCH resources set to the UE 4. Then, the cell
determines to modify the setting of the PUCCH resources, and
notifies it to the UE 4. Here, the cell notifies the UE 4 of
information indicating modification of the setting of the PUCCH
resources together with the symbol number to be allocated after the
modification (Mod_UE#4 (symbol #3)). Here, the symbol number is 3.
Consequently, the setting of the PUCCH resources is modified for
the UE 4.
[0459] Since the PUCCH resources set to the UE 1 have been
modified, the cell determines that the PUCCH resources set to the
UE 1 do not conflict with the PUCCH resources set to the UE 4.
Then, the cell determines to modify the setting of the PUCCH
resources, and notifies it to the UE 3. Here, the cell notifies the
UE 3 of information indicating modification of the setting of the
PUCCH resources together with the symbol number to be allocated
after the modification (Mod_UE#3 (symbol #3)). Here, the symbol
number is 3. Consequently, the setting of the PUCCH resources is
modified for the UE 3.
[0460] Consequently, the cell can allocate, for each UE that
performs communication via a different beam, a different resource
to the PUCCH of the UE. Thus, the cell requiring the beam sweeping
can receive, by switching between beams for each UE that performs
communication via a different beam, the PUCCH of the UE.
[0461] Consequently, the different resource can be dynamically
allocated, for each UE that performs communication via a different
beam, to the PUCCH of the UE. When the setting of the PUCCH
resources is unnecessary, the PUCCH resources can be released to
the UEs with the other beams by stopping the setting of the PUCCH
resources. There is no need to preset the PUCCH resources for each
beam as the methods disclosed in the second embodiment. This can
suppress reduction in the use efficiency of the radio
resources.
[0462] A method for notifying the information on starting,
modifying, and stopping the setting of the PUCCH resources will be
disclosed. The cell notifies the UE of the information on starting,
modifying, and stopping the setting of the PUCCH resources. The
cell notifies the information via the serving beam. When the cell
notifies the information via the serving beam, the beam ID may be
eliminated. The cell may notify the information via the
UE-dedicated signaling. Consequently, the UE can obtain the
information on starting, modifying, and stopping the setting of the
PUCCH resources for each UE via the beam via which the UE is
communicating.
[0463] The UE-dedicated signaling may be the RRC signaling. The
information on starting, modifying, and stopping the setting of the
PUCCH resources may be included in an RRC message. Alternatively,
the UE-dedicated signaling may be the L1/L2 control signaling. The
information on starting, modifying, and stopping the setting of the
PUCCH resources may be included in the downlink L1/L2 control
information. Since the UE can receive the setting relatively
earlier via the L1/L2 control signaling as the UE-dedicated
signaling, the setting latency can be reduced.
[0464] Alternatively, the UE-dedicated signaling may be the MAC
signaling. The information on starting, modifying, and stopping the
setting of the PUCCH resources may be included in the MAC control
information. Since the HARQ is applied when the MAC signaling is
used as the UE-dedicated signaling, the UE can perform reception at
a low reception error rate, and receive the setting relatively
earlier.
[0465] One example method for notifying the information on the
PUCCH resources and the information on starting, modifying, and
stopping the setting of the PUCCH resources will be disclosed. Both
of the information on the PUCCH resources and the information on
starting, modifying, and stopping the setting of the PUCCH
resources are notified via the RRC signaling. The RRC signaling
enables notification of a large amount of information at a low
reception error rate.
[0466] Another example of the notification method will be
disclosed.
[0467] The information on the PUCCH resources is notified via the
RRC signaling, and the information on starting, modifying, and
stopping the setting of the PUCCH resources is notified via the
L1/L2 control signaling. Since the information on starting,
modifying, and stopping the setting of the PUCCH resources is
notified via the L1/L2 control signaling, the UE can start, modify,
and stop the setting earlier. Starting, modifying, and stopping the
setting can be performed dynamically and earlier, which can
increase the use efficiency of the radio resources.
[0468] Yet another example of the notification method will be
disclosed.
[0469] The information on the PUCCH resources is notified via the
RRC signaling, and the information on starting, modifying, and
stopping the setting of the PUCCH resources is notified via the MAC
signaling. Since the information on starting, modifying, and
stopping the setting of the PUCCH resources is notified via the MAC
signaling, the notification can be made at a low error rate. The UE
can start, modify, and stop the settings relatively earlier.
Starting, modifying, and stopping the setting can be performed
dynamically, reliably, and relatively earlier, which can increase
the use efficiency of the radio resources.
[0470] Although disclosed is notification of the information on the
PUCCH resources and the information on starting, modifying, and
stopping the setting of the PUCCH resources from the cell via the
serving beam, the cell may notify at least one of the information
on the PUCCH resources and the information on starting, modifying,
and stopping the setting of the PUCCH resources via a single beam
covering the entire coverage of the cell as an alternative method.
Since the cell can notify the entire coverage of the cell of at
least one of the information on the PUCCH resources and the
information on starting, modifying, and stopping the setting of the
PUCCH resources, the signaling load can be reduced.
[0471] Alternatively, the cell may notify the UE of information on
the PUCCH resources for each UCI for each UE. The notification
methods previously described may be applied thereto. The cell can
set the PUCCH resources for each UCI, and the UE can transmit the
PUCCH for each UCI with the setting of the PUCCH resources set for
each UCI.
[0472] Priorities may be assigned to the symbol numbers to be
allocated to the PUCCHs. Priorities may be assigned for setting the
symbol numbers for the PUCCH resources. The highest priority is
assigned to the last symbol in one subframe, and lower priorities
are assigned to the forward symbols in order from the last symbol.
For example, when 1 subframe consists of 14 symbols ranging from
the symbol number 0 to the symbol number 13, the priority of the
symbol number 13 is the highest, and the priorities decrease as the
symbol numbers decrease, such as the symbol number 12 and then the
symbol number 11.
[0473] The PUCCH is allocated from a symbol with a higher priority.
For example, the PUCCH is allocated to a symbol with the highest
priority in starting the initial setting of the PUCCH resources.
When the PUCCH resource allocated to a symbol with a higher
priority is released by stopping its setting, the PUCCH resource to
be set to a symbol with the next priority may be modified to the
symbol with the higher priority whose PUCCH resource has been
released.
[0474] Consequently, the setting can be flexibly modified according
to the priorities. Preferentially using the last symbol as the
PUCCH resource enables the forward symbols with respect to the
PUCCH resource to be collectively used as at least one of the other
DL symbols and the other UL symbols. Furthermore, the number of
gaps can be reduced.
[0475] The PUCCHs may be allocated from the last symbol in
ascending order of length of the setting period of the PUCCH
resources. For example, the PUCCH is allocated to the symbol with
the highest priory in starting the initial setting of the PUCCH
resources. When the next setting period of the PUCCH resource is
shorter than the initial setting period of the PUCCH resource, the
PUCCH resource in the initial setting is modified to that for a
symbol with the next priority, and the next PUCCH resource is set
to the symbol with the highest priory.
[0476] Consequently, the number of times the forward symbols with
respect to the PUCCH resource are collectively generated can be
increased.
[0477] Although the first modification discloses dynamically
setting the PUCCH resources for each UE, the timing to notify, from
the cell to the UE, the information on the PUCCH resources and the
information on starting, modifying, and stopping the setting of the
PUCCH resources will be a problem.
[0478] What is disclosed is that the PUCCH of a beam different from
the beam for transmitting and receiving another symbol in a
subframe may be configured. Here, a predefined beam does not always
have the downlink resources in a subframe to which the PUCCH is
set. Thus, the cell may not be able to notify the UE of the
information in a PUCCH-resource setting subframe for each UE.
[0479] A method for solving such a problem will be disclosed.
[0480] The cell notifies the UE with timing prior to the
PUCCH-resource setting subframe for each UE. The cell may perform
transmission and reception via a beam in which a UE to be set
exists, with timing prior to the PUCCH-resource setting subframe
for each UE. The cell may then complete the signaling of the
information through such transmission and reception.
[0481] Since the PUCCH-resource setting subframe has already been
notified to the UE, when the cell makes a notification with timing
prior to the PUCCH-resource setting subframe for each UE, the UE
may apply the notified information in a PUCCH-resource setting
subframe after the notification.
[0482] The cell may also notify the UE of the timing to which the
setting is to be applied, when making the notification with timing
prior to the PUCCH-resource setting subframe for each UE. The cell
may make the notification as an offset. The cell may also notify,
for example, from how many PUCCH-resource setting subframes since
the notification the setting is to be applied. Consequently, the
setting can be made flexibly in time.
[0483] FIG. 19 illustrates one example sequence for setting the
PUCCHs for each UE and transmitting and receiving the SR. Since the
sequence illustrated in FIG. 19 includes the same Steps as those in
the sequence illustrated in FIG. 16, the same step numbers will be
assigned to the same Steps and the common description thereof will
be omitted. FIG. 19 illustrates a case where the cell notifies the
UE of the information on the PUCCH resources for each UE and the
information on starting, modifying, and stopping the setting of the
PUCCH resources for each UE separately.
[0484] In Step ST2801, the cell sets, to the UE, a PUCCH resource
configuration for each UE.
[0485] In Step ST2802, the cell notifies the UE of the information
on the PUCCH resources for each UE. The cell may notify the
information on the PUCCH resources for each UE via a beam via which
the cell communicates with the UE. The cell notifies the
information via the RRC-dedicated signaling.
[0486] Upon receipt of the information on the PUCCH resources for
each UE in Step ST2802, the UE stores the PUCCH resource
configuration in Step ST2803.
[0487] In Step ST2804, the cell determines to start the setting of
the PUCCH resources for the UE. According to the first
modification, the cell determines a symbol to be allocated to the
UE as well as determining to start the setting of the PUCCH
resources for the UE. Here, the cell makes the settings for the UEs
whose serving beams are different to prevent the PUCCH resource
timings from coinciding with each other.
[0488] In Step ST2805, the cell notifies the UE of information on
starting the setting of the PUCCH resources. The cell also notifies
the symbol number information to be allocated as the PUCCH
resources. The cell includes, in the downlink L1/L2 control
information, these pieces of information, and notifies the UE of
the information via the downlink L1/L2 control signaling.
[0489] Upon receipt of the information on starting the setting of
the PUCCH resources in Step ST2805, the UE sets the PUCCH resource
configuration of its own UE in Step ST2813, using the information
on the PUCCH resources for each UE that has been stored in Step
ST2803, and the symbol number received in Step ST2805.
[0490] After notification of the information on starting the
setting of the PUCCH resources and the symbol number information to
the UE in Step ST2805, the cell starts reception in Step ST2806
with the PUCCH resource configuration set to the UE.
[0491] Upon the occurrence of transmission of an uplink signal, the
UE transmits the SR with this PUCCH resource setting. In the
example of FIG. 19, however, the UE does not have any uplink data
under such a state.
[0492] In Step ST2807, the cell determines to modify the PUCCH
resource setting for the UE, and determines the symbols to be
allocated to the UE after the modification. Here, the cell makes
the settings for the UEs whose serving beams are different to
prevent the PUCCH resource timings from coinciding with each other.
The cell may make the setting in order of priorities of the symbol
numbers to be allocated to the PUCCHs.
[0493] In Step ST2808, the cell notifies the UE of information on
modifying the setting of the PUCCH resources. The cell also
notifies the symbol number information to be allocated after
modification as the PUCCH resources. The cell includes, in the
downlink L1/L2 control information, these pieces of information,
and notifies the UE of the information via the downlink L1/L2
control signaling. The notification via the L1/L2 control signaling
can reduce the setting time as much as possible.
[0494] Upon receipt of the information on modifying the setting of
the PUCCH resources and the symbol number in Step ST2808, the UE
modifies the setting of the PUCCH resources of its own UE in Step
ST2809.
[0495] After notification of the information on modifying the
setting of the PUCCH resources and the symbol number information to
the UE in Step ST2808, the cell starts reception in Step ST2810
with the PUCCH resource configuration modified for the UE.
[0496] In Step ST2811, the UE determines whether the uplink data
has been generated. When the uplink data is not generated in Step
ST2811, the UE returns to Step ST2811 to repeat the determination
on whether the uplink data has been generated. When the uplink data
has been generated in Step ST2811, the UE proceeds to Step
ST2812.
[0497] In Step ST2812, the UE transmits the SR to the cell via the
serving beam with the modified PUCCH resource configuration for the
SR.
[0498] The cell, which has started reception in Step ST2810 with
the PUCCH resources modified for the UE, receives the SR
transmitted from the UE in Step ST2812.
[0499] Upon receipt of the SR from the UE, the cell performs a
process for starting the uplink communication. Consequently, the
uplink communication is started between the UE and the cell.
[0500] Application of such a method can produce the same advantages
as those in the examples previously described.
[0501] Setting the PUCCH resources to the UE in advance and
appropriate notification of starting, modifying, and stopping the
setting of the PUCCH resources enables the PUCCH resources to be
set earlier according to a connected state of the UE. This can
further suppress reduction in the use efficiency of the
resources.
Second Modification of Second Embodiment
[0502] The first modification of the second embodiment discloses
increasing the use efficiency of the radio resources through
setting of the PUCCH resources for each UE to the UE. With the
periodic setting of the PUCCH resources, however, communication
needs to be always performed, with the timing, via a beam to which
the PUCCH resources are set. In the presence of communication
requiring the low latency via the other beams, a problem of a
communication failure via a beam to which the PUCCH resources are
set arises.
[0503] The second modification will disclose a method for solving
such a problem.
[0504] The cell sets the PUCCH resources to the UE in a subframe
identical to the subframe in which the DL resources are configured
for the beams via which the UE communicates. The UE transmits the
PUCCH in a subframe identical to the subframe in which the downlink
signal for the serving beam is transmitted. In the NR, the
self-contained subframe that consists of DL resources and UL
resources in the same subframe is proposed. This self-contained
subframe may be used in the second modification.
[0505] The cell notifies the UE of whether the PUCCH can be
transmitted in a subframe identical to the subframe in which the DL
resources are configured for the beams via which the UE
communicates. The cell notifies the UE of whether the PUCCH can be
transmitted via the serving beam using the downlink L1/L2 control
signaling, with timing requiring transmission of the PUCCH.
Information on whether the PUCCH can be transmitted may be
provided. The cell may include, in the downlink control
information, the information on whether the PUCCH can be
transmitted, and notify the UE of the information via the downlink
L1/L2 control signaling.
[0506] When the UE receives the information on whether the PUCCH
can be transmitted and the information indicates that the UE can
transmit the PUCCH, the UE can transmit the PUCCH in a subframe in
which the information on whether the PUCCH can be transmitted has
been received. When the UE receives the information on whether the
PUCCH can be transmitted and the information indicates that the UE
cannot transmit the PUCCH, the UE cannot transmit the PUCCH in a
subframe in which the information on whether the PUCCH can be
transmitted has been received. When the UE receives the information
on whether the PUCCH can be transmitted and cannot receive
information indicating that the PUCCH can be transmitted, the UE
may not be able to transmit the PUCCH in the subframe.
[0507] It is possible to provide only the information indicating
that the PUCCH can be transmitted, and omit the information
indicating that the PUCCH cannot be transmitted. Only upon receipt
of the information indicating that the PUCCH can be transmitted,
the UE can transmit the PUCCH in a subframe in which the
information indicating that the PUCCH can be transmitted has been
received.
[0508] A setting method to the UE will be disclosed.
[0509] The cell transmits the information on whether the PUCCH can
be transmitted, to the UE within preset PUCCH resources to instruct
the UE whether the PUCCH can be transmitted. The preset PUCCH
resources may include the timing to set the PUCCH resources. The
preset PUCCH resources may include at least the timing per
subframe. The cell may notify and set, to the UE, information on
the PUCCH resources disclosed in the second embodiment or the first
modification of the second embodiment.
[0510] Upon receipt of the information indicating that the PUCCH
can be transmitted, the UE can transmit the PUCCH. Conversely, upon
receipt of information indicating that the PUCCH cannot be
transmitted, the UE cannot transmit the PUCCH.
[0511] Although the advanced notification of the setting of the
PUCCH resources is disclosed, a part or the entirety of the setting
of the PUCCH resources may be notified together with the
information on whether the PUCCH can be transmitted. Resource
settings per time unit smaller than a subframe may be notified
together with the information on whether the PUCCH can be
transmitted. For example, the symbol number information to be
allocated to the PUCCH is notified together with the information on
whether the PUCCH can be transmitted. This enables dynamic and
flexible allocation of the symbols.
[0512] Alternatively, notification of a part or the entirety of the
setting of the PUCCH resources may indicate that the PUCCH can be
transmitted. This can omit the information indicating that the
PUCCH can be transmitted. Information to be notified together with
the information on whether the PUCCH can be transmitted may be
restricted to a few pieces of information. Presetting most of the
PUCCH resources can shorten the processing time from receipt of the
information indicating that the PUCCH can be transmitted to
transmission of the PUCCH. The UE can transmit the PUCCH in a
subframe identical to the subframe in which the information
indicating that the PUCCH can be transmitted has been received.
[0513] The cell need not transmit and receive the beam via which
the UE communicates, in a subframe in which the PUCCH resources are
set to the UE. Since the UE cannot receive the downlink L1/L2
control signaling from the serving beam under such a state, the UE
cannot receive the information on whether the PUCCH can be
transmitted. Thus, the operations of the UE become unclear, and the
UE may wrongly transmit the PUCCH.
[0514] As previously disclosed, when the UE receives the
information on whether the PUCCH can be transmitted and cannot
receive the information indicating that the PUCCH can be
transmitted, preventing the UE from being able to transmit the
PUCCH in the subframe can avoid unnecessary transmission of the
PUCCH from the UE. Consequently, the power consumption of the UE
and the uplink interference power can be reduced.
[0515] Another setting method to the UE will be disclosed.
[0516] The cell notifies the UE of the setting of the PUCCH
resources except for the timing in advance, so that the UE follows
the setting of the PUCCH resources except for the timing.
Notification of the information on the PUCCH resources disclosed in
the second embodiment or the first modification of the second
embodiment may be applied to the advanced setting of the PUCCH
resources except for the timing.
[0517] The cell instructs the UE whether the PUCCH can be
transmitted with an arbitrary timing. The cell notifies the UE of
the information on whether the PUCCH can be transmitted. Resource
settings per time unit smaller than a subframe may be notified
together with the information on whether the PUCCH can be
transmitted. The cell notifies, for example, a symbol number. Upon
receipt of the information indicating that the PUCCH can be
transmitted, the UE can transmit the PUCCH. Conversely, upon
receipt of the information indicating that the PUCCH cannot be
transmitted, the UE cannot transmit the PUCCH.
[0518] Although the advanced notification of the setting of the
PUCCH resources except for the timing is disclosed, a part or the
entirety of the setting of the PUCCH resources except for the
timing may be notified together with the information on whether the
PUCCH can be transmitted. For example, the frequency resource
information of the PUCCH may be notified together with the
information on whether the PUCCH can be transmitted. This enables
dynamic and flexible allocation of the frequency resources.
[0519] Notification of a symbol number or a part or the entirety of
the setting of the PUCCH resources may indicate that the PUCCH can
be transmitted. This can omit the information indicating that the
PUCCH can be transmitted.
[0520] Information to be notified together with the information on
whether the PUCCH can be transmitted may be restricted to a few
pieces of information. Presetting most of the PUCCH resources can
shorten the processing time from receipt of the information
indicating that the PUCCH can be transmitted to transmission of the
PUCCH. Thus, the PUCCH can be transmitted in a subframe identical
to the subframe in which the UE has received the information
indicating that the PUCCH can be transmitted.
[0521] Consequently, the UE can determine whether the PUCCH can be
transmitted, according to the information on whether the PUCCH can
be transmitted that is included in the L1/L2 control signaling to
be transmitted via the serving beam. The cell causes the UE not to
transmit the PUCCH with the PUCCH resources set to the UE, which
enables the cell to use the PUCCH resources for the others. The
PUCCH resources can be used as, for example, resources for downlink
communication. The cell can dynamically determine the other use of
the PUCCH resources.
[0522] Particularly, associating a downlink control signal with
transmission of the PUCCH for the SR enables dynamic setting of the
PUCCH resources according to the determination by the cell. The
cell can dynamically change the beams to be transmitted and
received, in the MBF requiring the beam sweeping. This eliminates
the need for performing transmission and reception with the PUCCH
resource timing preset to each beam. This can flexibly accommodate,
for example, the radio propagation environment fluctuating from
moment to moment, variations in the cell load, or a required
communication service.
[0523] Upon receipt of the information indicating that the PUCCH
can be transmitted and in the presence of the UCI to be transmitted
with the PUCCH, the UE transmits the PUCCH. In the absence of the
UCI to be transmitted with the PUCCH, the UE does not transmit the
PUCCH. For example, in the presence of the SR to be transmitted,
the UE transmits the PUCCH for the SR. Upon receipt of the
information indicating that the PUCCH cannot be transmitted, the UE
does not transmit the PUCCH regardless of the presence or absence
of the UCI to be transmitted with the PUCCH. For example, even in
the presence of the SR to be transmitted, the UE does not transmit
the PUCCH for the SR.
[0524] The UE waits to transmit the UCI that is not transmitted
when the UE cannot transmit the PUCCH, until receiving the next
information indicating that the PUCCH can be transmitted. This
enables reliable transmission of the UCI. As an alternative method,
the UE may discard the UCI that is not transmitted. Alternatively,
the UE may discard the UCI that is not transmitted, next time when
a UCI of the same type is generated. Consequently, the buffer
required for the UE can be reduced.
[0525] FIG. 20 illustrates one example method for setting the PUCCH
resources in a subframe identical to that for the DL resources for
the serving beam of the UE. A case where the number of times the
beam sweeping is performed is four will be described herein. The
number of symbols to be allocated to the PUCCH resources is 1
within 1 subframe. Here, the symbol whose symbol number is 13 is
allocated to the PUCCH resources. The symbol number to be allocated
to the PUCCH resources may be fixed. The number of symbols to be
allocated to the downlink L1/L2 control signaling is 1 within 1
subframe. Here, the symbol whose symbol number is 0 is allocated to
the downlink L1/L2 control signaling. The symbol number to be
allocated to the downlink L1/L2 control signaling may be fixed.
[0526] The cell transmits and receives, in a subframe number 0, a
beam 2002 with a beam number 2. The cell includes, in the UCI,
information on whether the PUCCH resources can be transmitted for
each UE, and notifies the information to the UE that communicates
using the beam number 2 via downlink L1/L2 control signaling 2001
of the beam number 2. The cell may include, in the UCI, the symbol
number information together with the information on whether the
PUCCH resources can be transmitted, and notify the UE of the
information.
[0527] The UE that performs transmission and reception via the beam
2002 with the beam number 2 receives the downlink L1/L2 control
signaling 2001 with the subframe number 0, and receives the
information on whether the PUCCH resources can be transmitted and
the symbol number. Upon receiving that the PUCCH resources can be
transmitted, the UE sets the PUCCH resources from the information
on the preset PUCCH resources and the symbol number, so that the UE
can transmit the PUCCH resources. The UE with the UCI to be
transmitted transmits the PUCCH with the PUCCH resources. Here, the
UE transmits a PUCCH 2003 with the beam #2.
[0528] Upon receiving that the PUCCH resources cannot be
transmitted, the UE cannot transmit the PUCCH. Even in the presence
of the UCI to be transmitted, the UE does not transmit the
PUCCH.
[0529] The cell transmits and receives, in the next subframe number
1, a beam 2002 with the beam number 3. The cell includes, in the
UCI, the information on whether the PUCCH resources can be
transmitted for each UE, and notifies the UE that communicates
using the beam number 3 of the information via downlink L1/L2
control signaling 2004 with the beam number 3. The cell may
include, in the UCI, the symbol number information together with
the information on whether the PUCCH resources can be transmitted,
and notify the UE of the information.
[0530] The UE that performs transmission and reception via the beam
2002 with the beam number 3 receives the L1/L2 control signaling
2004 with the subframe number 1, and receives the information on
whether the PUCCH resources can be transmitted and the symbol
number. Upon receiving that the PUCCH resources can be transmitted,
the UE sets the PUCCH resources from the information on the preset
PUCCH resources and the symbol number, so that the UE can transmit
the PUCCH resources. The UE with the UCI to be transmitted
transmits the PUCCH with the PUCCH resources. Here, the UE
transmits a PUCCH 2005 with the beam #3.
[0531] Upon receiving that the PUCCH resources cannot be
transmitted, the UE cannot transmit the PUCCH. Even in the presence
of the UCI to be transmitted, the UE does not transmit the
PUCCH.
[0532] The cell transmits and receives, in the next subframe number
2, a beam 2002 with a beam number 1. The cell includes, in the UCI,
the information on whether the PUCCH resources can be transmitted
for each UE, and notifies the UE that communicates using the beam
number 1 of the information via downlink L1/L2 control signaling
2006 with the beam number 1. The cell may include, in the UCI, the
symbol number information together with the information on whether
the PUCCH resources can be transmitted, and notify the UE of the
information.
[0533] The UE that performs transmission and reception via the beam
2002 with the beam number 1 receives the L2/L2 control signaling
2006 with the subframe number 2, and receives the information on
whether the PUCCH resources can be transmitted and the symbol
number. Upon receiving that the PUCCH resources can be transmitted,
the UE sets the PUCCH resources from the information on the preset
PUCCH resources and the symbol number, so that the UE can transmit
the PUCCH resources. The UE with the UCI to be transmitted
transmits the PUCCH with the PUCCH resources. Here, the UE
transmits a PUCCH 2007 with the beam #1.
[0534] Upon receiving that the PUCCH resources cannot be
transmitted, the UE cannot transmit the PUCCH. Even in the presence
of the UCI to be transmitted, the UE does not transmit the
PUCCH.
[0535] The cell transmits and receives, in the next subframe number
3, a beam 2002 with a beam number 0. The cell includes, in the UCI,
the information on whether the PUCCH resources can be transmitted
for each UE, and notifies the UE that communicates using the beam
number 0 of the information via downlink L1/L2 control signaling
2008 with the beam number 0. The cell may include, in the UCI, the
symbol number information together with the information on whether
the PUCCH resources can be transmitted, and notify the UE of the
information.
[0536] The UE that performs transmission and reception via the beam
2002 with the beam number 0 receives the L1/L2 control signaling
2008 with the subframe number 3, and receives the information on
whether the PUCCH resources can be transmitted and the symbol
number. Upon receiving that the PUCCH resources can be transmitted,
the UE sets the PUCCH resources from the information on the preset
PUCCH resources and the symbol number, so that the UE can transmit
the PUCCH resources. The UE with the UCI to be transmitted
transmits the PUCCH with the PUCCH resources. Here, the UE
transmits a PUCCH 2009 with the beam #0.
[0537] Upon receiving that the PUCCH resources cannot be
transmitted, the UE cannot transmit the PUCCH. Even in the presence
of the UCI to be transmitted, the UE does not transmit the
PUCCH.
[0538] Consequently, the UE can transmit and receive the PUCCH
along with the timing of the beam via which the cell performs
transmission and reception. The UE can also determine whether the
PUCCH can be transmitted, according to the information on whether
the PUCCH can be transmitted that is included in the L1/L2 control
signaling to be transmitted via the serving beam. Associating a
downlink control signal with transmission of the PUCCH enables
dynamic setting of the PUCCH resources according to the
determination by the cell.
[0539] FIG. 21 illustrates one example sequence for setting the
PUCCH resources in the subframe identical to that for the DL
resources and transmitting and receiving the SR. Since the sequence
illustrated in FIG. 21 includes the same Steps as those in the
sequence illustrated in FIG. 16, the same step numbers will be
assigned to the same Steps and the common description thereof will
be omitted.
[0540] In Step ST3001, the cell sets, to the UE, a PUCCH resource
configuration except for the timing.
[0541] In Step ST3002, the cell notifies the UE of information on
the PUCCH resources except for the timing. The cell may notify the
information on the PUCCH resources via a beam via which the cell
communicates with the UE. The cell notifies the information on the
PUCCH resources via the RRC-dedicated signaling.
[0542] Upon receipt of the information on the PUCCH resources
except for the timing in Step ST3002, the UE stores the PUCCH
resource configuration in Step ST3003.
[0543] In Step ST3004, the UE determines whether the uplink data
has been generated. When the uplink data is not generated in Step
ST3004, the UE returns to Step ST3004 to repeat the determination
on whether the uplink data has been generated. When the uplink data
has been generated in Step ST3004, the UE proceeds to Step
ST3005.
[0544] In Step ST3005, the UE waits to transmit the SR, and stores
the uplink data in the buffer.
[0545] In Step ST3006, the cell determines to perform, in an
arbitrary subframe, transmission and reception to and from the beam
via which the UE communicates. The cell also determines that the
PUCCH can be transmitted to the UE in the subframe.
[0546] In Step ST3007, the cell notifies, in the subframe, the UE
of the information indicating that the PUCCH can be transmitted.
Here, the cell notifies the symbol number information together with
the information indicating that the PUCCH can be transmitted. The
cell includes, in the downlink L1/L2 control information, these
pieces of information, and notifies the UE of the information via
the downlink L1/L2 control signaling.
[0547] Upon receipt of the information indicating that the PUCCH
can be transmitted in Step ST3007, the UE sets, in Step ST3008, the
PUCCH resource configuration of its own UE in a subframe identical
to the subframe in which the information has been received, using
the information on the PUCCH resources for each UE that has been
stored in Step ST3003, and the symbol number received in Step
ST3007.
[0548] In Step ST3009, the UE transmits the SR that has been put on
hold to the cell via the serving beam, with the PUCCH resource
configuration for the SR that has been set in Step ST3008.
[0549] After notification of the information indicating that the
PUCCH can be transmitted and the symbol number information to the
UE in Step ST3007, the cell starts reception in Step ST3010 with
the PUCCH resource configuration set in the same subframe to the
UE.
[0550] The cell, which has started reception in Step ST3010 with
the PUCCH resource configuration set to the UE, receives the SR
transmitted from the UE in Step ST3009.
[0551] Upon receipt of the SR from the UE, the cell performs a
process for starting the uplink communication. Consequently, the
uplink communication is started between the UE and the cell.
[0552] Application of the methods disclosed in the second
modification enables setting of the PUCCH resources when the beam
sweeping in the MBF comes into operation. The cell sets the PUCCH
resources to the UE according to the methods disclosed in the
second modification, which enables transmission and reception of
the PUCCH via the beam via which the UE is communicating and
enables the uplink communication from the UE to the cell.
[0553] Consequently, the UE can transmit and receive the PUCCH
along with the timing of the beam via which the cell performs
transmission and reception. Consequently, the UE can determine
whether the PUCCH can be transmitted, according to the information
on whether the PUCCH can be transmitted that is included in the
L1/L2 control signaling to be transmitted via the serving beam.
This eliminates the need for controlling the beam via which the
PUCCH is transmitted and received, with the PUCCH resources set to
the UE. Thus, setting the PUCCH resources to the UE and controlling
for transmitting and receiving the PUCCH can be facilitated.
[0554] According to the disclosed method, the cell notifies the UE
of whether the PUCCH can be transmitted in the subframe identical
to the subframe in which the DL resources are configured for the
beams via which the UE communicates. The cell may notify not
whether the PUCCH can be transmitted in the same subframe but
whether the PUCCH can be transmitted in a subframe after an offset
from a subframe in which whether the PUCCH can be transmitted has
been notified.
[0555] Offset information indicating an offset value from the
subframe in which whether the PUCCH can be transmitted has been
notified may be provided. The cell notifies the UE of the offset
information together with the information on whether the PUCCH can
be transmitted. The UE transmits the PUCCH in a subframe distant by
the offset value from the subframe in which the information on
whether the PUCCH can be transmitted has been received. Upon
receipt of the information indicating that the PUCCH cannot be
transmitted, the UE does not transmit the PUCCH in the subframe
distant by the offset value from the subframe in which the
information on whether the PUCCH can be transmitted has been
received.
[0556] Such methods may be applied when the cell recognizes the
next transmission/reception timing of the beam via which the UE is
communicating. Alternatively, such methods may be applied when the
cell schedules the next transmission/reception timing of the beam
via which the UE is communicating. Alternatively, such methods may
be applied when the cell determines the next transmission/reception
timing of the beam via which the UE is communicating in notifying
the UE of the information indicating that the PUCCH can be
transmitted.
[0557] Consequently, the UE need not set or transmit the PUCCH in a
subframe identical to the subframe in which the information
indicating that the PUCCH can be transmitted has been received.
Thus, the UE can transmit the PUCCH even when it takes some time
for the UE to perform processes for transmitting the PUCCH, such as
demodulating, decoding, coding, and modulating the PUCCH.
[0558] The UE may notify, in advance, the cell of the time or the
capability required for the processes such as demodulating,
decoding, coding, and modulating the PUCCH. The UE may notify the
time or the capability as UE capability information. The cell may
determine the offset value, using the time or the capability
notified from the UE and required for the processes such as
demodulating, decoding, coding, and modulating the PUCCH.
[0559] For example, when the UE can perform, in the same subframe,
processes ranging from receiving whether the PUCCH can be
transmitted to transmitting the PUCCH, the cell notifies the UE of
0 as the offset. When the offset is 0, the offset information may
be omitted. For example, when it takes 2 subframes for the UE to
perform the processes ranging from receiving whether the PUCCH can
be transmitted to transmitting the PUCCH, the cell notifies the UE
of 2 as the offset. Here, the cell may consider communication
states of the other beams, and set 2 or more as the offset and
notify it to the UE.
[0560] According to the disclosed methods, one subframe is
allocated to one beam. The whole one subframe may be allocated not
only to the single beam but to a plurality of beams. For example in
one subframe, only a symbol to which a downlink L1/L2 control
signal is mapped and a symbol including the PUCCH resources may be
allocated to the same beam, and the other symbols may be allocated
to the other beams. Consequently, the cell can further flexibly
operate the beams, and increase the use efficiency of the radio
resources of the cell.
[0561] For example, not only a downlink L1/L2 control signal of one
beam but also downlink L1/L2 control signals of a plurality of
beams may be allocated to one subframe. The downlink L1/L2 control
signal may be allocated for each symbol. Not only the PUCCH
resource of one beam but also the PUCCH resources of a plurality of
beams may be allocated to one subframe. The PUCCH resource may be
allocated for each symbol. The cell can receive the PUCCH
transmission from the UE communicating with each beam, via a
plurality of beams in one subframe.
[0562] A symbol to which the L1/L2 control signal may be mapped may
be restricted in one subframe. The maximum value may be set to the
number of such symbols. The UE may receive the symbol to which the
L1/L2 control signal may be mapped to determine the presence or
absence of the L1/L2 control signal for the serving beam. The cell
may notify the UE of the maximum value in advance. The cell may
broadcast the maximum value as information for each cell, or make
the notification via the UE-dedicated signaling. Alternatively, the
maximum value may be statically determined in, for example, a
standard. The UE may receive only the symbol of the maximum value,
and may not receive the subframe when the UE cannot receive the
downlink L1/L2 control information addressed to its own UE.
[0563] Since application of such a method increases the
communication opportunities via each beam, the SR transmission idle
time can be shortened in the UE. Thus, the latency from generation
of the uplink data from the UE to start of the uplink communication
can be shortened.
[0564] When the L1/L2 control signals of a plurality of beams are
allocated to a plurality of symbols in one subframe, the UE
receives not the first symbol but the plurality of symbols. When
the number of symbols to which the L1/L2 control signals are
allocated is fixed, the UE can receive the L1/L2 control signals to
be transmitted via the serving beam, upon receipt of the number of
symbols. When a beam not requiring the L1/L2 control signals is
generated while the number of symbols is fixed in advance, the
symbols will be wasted.
[0565] A method for solving such a problem will be disclosed.
[0566] The cell may notify information on the number of symbols to
be used for the L1/L2 control signals for each subframe. The
information may be information common to cells. The information may
be included in the downlink L1/L2 control information to be
notified. The information may be L1/L2 control information
dedicated to the UE. Alternatively, the information may be L1/L2
control information common to cells. Application of the L1/L2
control information common to cells can reduce the amount of
information.
[0567] The physical channel to which the information on the number
of symbols to be used for the L1/L2 control signals is mapped may
be individually provided, and notified to the UE for each subframe.
The physical channel may be mapped to the first symbol in a
subframe.
[0568] Although what is disclosed is that the cell notifies the
information on the number of symbols to be used for the L1/L2
control signals for each subframe, the cell may periodically make
the notification. This method may be applied when the L1/L2 control
signals of a plurality of beams are periodically allocated to a
plurality of symbols in one subframe. The cell may notify, in
advance, the UE of the period information and offset information
indicating the starting point. The cell may broadcast such
information as information for each cell, or make the notification
via the UE-dedicated signaling. Alternatively, such information may
be statically determined in, for example, a standard.
[0569] This enables flexible settings of the L1/L2 control
signaling when the beam sweeping in the MBF comes into operation.
The second modification enables setting of the PUCCH resources when
the beam sweeping in the MBF comes into operation.
[0570] When all the beams in the cell cannot be formed with the
same timing in the MBF, consecutively sweeping all the beams to
allow transmission and reception of a control channel common to the
cells is being studied in the NR (see Non-Patent Document 12). A
portion in which all the beams are consecutively swept will also be
referred to as a beam sweeping block.
[0571] When the PUCCH resource timing overlaps such a beam sweeping
block timing, no symbol can be allocated to the PUCCH. In such a
case, the beam sweeping block timing may be excluded as the PUCCH
resource timing. The cell may not set the PUCCH resources when the
beam sweeping block timing overlaps the PUCCH resource timing set
to the UE. This disables transmission of the PUCCH.
[0572] Alternatively, the UE does not set the PUCCH resources when
the beam sweeping block timing overlaps the PUCCH resource timing.
Transmission of the PUCCH may be disabled. This may be
predetermined in, for example, a standard. The cell notifies the UE
of, for example, the beam sweeping block period. Thus, the UE can
recognize the beam sweeping block timing.
[0573] This can prevent the unnecessary transmission of the PUCCH
in the beam sweeping block. Consequently, the power consumption of
the UE can be reduced.
[0574] Another method to be applied when the PUCCH resource timing
overlaps the beam sweeping block timing will be disclosed.
[0575] The beam sweeping block is set to a self-contained subframe.
The uplink transmission is enabled in transmission of each beam in
a downlink beam sweeping block. A symbol for the uplink
transmission may be allocated to the PUCCH.
[0576] A beam with the timing overlapping transmission of the PUCCH
in a beam sweeping block may be not a beam requiring the
transmission of the PUCCH but another beam. Here, the symbol for
the uplink transmission of the beam requiring the transmission of
the PUCCH in the beam sweeping block may be allocated to the PUCCH.
This may be predetermined in, for example, a standard.
[0577] Even when the PUCCH resource timing overlaps the beam
sweeping block timing, the PUCCH can be transmitted with the PUCCH
resource timing or the beam sweeping block timing.
[0578] When the PUCCH resource timing overlaps the uplink beam
sweeping block timing, a part of symbols in an uplink beam sweeping
block may be allocated to the PUCCH.
[0579] The beam with the timing overlapping transmission of the
PUCCH in the uplink beam sweeping block may be not a beam requiring
the transmission of the PUCCH but another beam. Here, a part of
symbols of beams requiring the transmission of the PUCCH in the
uplink beam sweeping block may be allocated to the PUCCH. This may
be predetermined in, for example, a standard.
[0580] Even when the PUCCH resource timing overlaps the uplink beam
sweeping block timing, the PUCCH can be transmitted with the PUCCH
resource timing or the uplink beam sweeping block timing.
[0581] When the PUCCH resource timing overlaps the downlink beam
sweeping block timing in the frequency division duplex (FDD), no
problem occurs because the frequencies are different. However, when
the PUCCH resource timing overlaps the uplink beam sweeping block
timing, a problem occurs. Here, the method disclosed on the uplink
beam sweeping block may be applied thereto. Consequently, the same
advantages can be produced.
Third Embodiment
[0582] The second embodiment to the second modification of the
second embodiment disclose methods for allocating the PUCCH of each
beam to different resources as methods for transmitting and
receiving the PUCCH in the MBF requiring the beam sweeping. The
third embodiment will disclose another method as the method for
transmitting and receiving the PUCCH in the MBF requiring the beam
sweeping.
[0583] The cell assigns priorities for receiving the PUCCH to
beams. The cell assigns the priorities for receiving the PUCCH to
the beams, and receives the PUCCH via the target beam according to
the priorities.
[0584] The cell may assign priorities to UEs. The cell may assign
priorities to beams via which the UEs communicate, using the
priorities of the UEs. For example, the cell assigns priorities to
beams in descending order of the priorities among the UEs
communicating via the same beam.
[0585] The following (1) to (9) will be disclosed as examples of an
indicator for assigning priorities.
[0586] (1) a communication service type: For example, a service
requiring urgency is assigned a higher priority.
[0587] (2) a requested QoS: For example, the QoS requiring higher
throughput is assigned a higher priority.
[0588] (3) a requested latency: For example, a UE requiring lower
latency is assigned a higher priority.
[0589] (4) a load of each beam: For example, a beam with a higher
load is assigned a higher priority.
[0590] (5) UE capability: For example, a UE with higher UE
capability is assigned a higher priority.
[0591] (6) an SR period: For example, a UE with a longer SR period
is assigned a higher priority.
[0592] (7) the number of UEs for each beam: For example, a beam for
many UEs is assigned a higher priority.
[0593] (8) communication quality: For example, a beam with superior
communication quality is assigned a higher priority.
[0594] (9) combinations of (1) to (8) above
[0595] The cell may assign, in advance, priorities for receiving
the PUCCH to beams according to the aforementioned indicators. The
cell may assign, in advance, a priority to at least one of
transmission and reception of a beam according to the
aforementioned indicators. The cell may assign, in advance,
priorities for receiving the PUCCH to the UEs according to the
aforementioned indicators, and assign priorities to beams according
to the priorities of the UEs.
[0596] The cell receives the PUCCH via the target beam according to
the set priorities. For example, when the beam with superior
communication quality is assigned a higher priority, the beam with
superior communication quality is set to a beam via which the PUCCH
is to be received. For example, the beam in which the UE with a
higher priority exists is set to the beam via which the PUCCH is to
be received.
[0597] When the transmission timing of the PUCCH by a UE with a
beam conflicts with the transmission timing of the PUCCH by a UE
with another beam, the cell determines via which one of the beams
transmission and reception should be preferentially performed,
according to the set priorities. The same may hold true when the
transmission timing of the PUCCH by the UE with the beam conflicts
with the scheduling timing for performing transmission and
reception via the other beam, not limited to when the transmission
timing of the PUCCH by the UE with the beam conflicts with the
transmission timing of the PUCCH by the UE with the other beam.
[0598] An example of assigning priorities to beams via which the
UEs communicate, using the priorities of the UEs will be disclosed.
When the aforementioned timings conflict with each other, with the
timings, the cell receives the PUCCH via a beam via which the UE
with a higher priority communicates, and does not receive the PUCCH
via a beam via which the UE with a lower priority communicates. The
UE with a higher priority with the timings transmits the PUCCH to
the cell. Although the UE with a lower priority with the timings
transmits the PUCCH to the cell, the cell does not receive the
PUCCH.
[0599] Although the UE with a lower priority transmits the PUCCH
with the conflicting timings, no problem occurs because the cell
communicates via a beam different from the beam via which the UE
communicates. Thus, the reception signals do not conflict with each
other in the cell.
[0600] Even when the transmission timings of the PUCCH conflict
with each other, the setting for the PUCCH resources can be
implemented regardless of beams, by assigning priorities to the
beams and transmitting and receiving the PUCCH via the beams
according to the priorities. Thus, it is possible to avoid
complexity in the processes that is caused by, for example,
addition of a process for the UE.
[0601] Although the cell does not receive the PUCCH from the UE
with a lower priority according to the previously disclosed method,
the UE with a lower priority performs transmission with the timing
set for transmitting the PUCCH each time. These transmissions are
unnecessary, which will cause problems of increase in the power
consumption in the UE and increase in the uplink interference
power.
[0602] A method for solving such a problem will be disclosed.
[0603] The UE that is receiving the BSR is assigned the lowest
priority. The cell assigns the lowest priority to the UE that is
receiving the BSR. Upon completion of the transmission of the
uplink scheduling (uplink grant) for the BSR, the cell restores the
priority of the UE to its original. Application of such a method
enables transmission and reception of the PUCCH via the beam via
which the UE with a lower priority communicates. This can avoid the
UE with a lower priority from repeated transmission of unnecessary
PUCCHs.
[0604] Another method will be disclosed. The cell notifies the UE
with a lower priority of the information on whether the PUCCH can
be transmitted, in a subframe with the PUCCH resources via the beam
via which the UE communicates. The cell maps the downlink L1/L2
control signal of the beam via which the UE communicates to a
subframe with the PUCCH resources, and includes the information
indicating whether the PUCCH can be transmitted in the downlink
L1/L2 control signal of the beam. The cell may include only the
information indicating that the PUCCH cannot be transmitted in the
downlink L1/L2 control signal of the beam.
[0605] The resources for the downlink L1/L2 control signal may be
set per symbol. The resources for the downlink L1/L2 control signal
may be set to one symbol. The UE receives the downlink L1/L2
control signal of the beam via which its own UE communicates, in
the subframe with the PUCCH resources to determine whether the
PUCCH can be transmitted. Upon receiving that the PUCCH cannot be
transmitted, the UE does not transmit the PUCCH. The methods
disclosed in the second modification of the second embodiment may
be applied to transmission of the information on whether the PUCCH
can be transmitted.
[0606] Application of the methods can prevent the UE with a lower
priority from transmitting the PUCCH with the conflicting timings.
This can avoid repeated transmission of unnecessary PUCCHs from the
UE with a lower priority.
[0607] FIGS. 22 and 23 illustrate one example sequence for
transmitting and receiving the SR when priorities for receiving the
PUCCH are assigned to beams. FIGS. 22 and 23 are connected across a
location of a border BL1. Since the sequence illustrated in FIGS.
22 and 23 includes the same Steps as those in the sequence
illustrated in FIG. 19, the same step numbers will be assigned to
the same Steps and the common description thereof will be omitted.
FIGS. 22 and 23 illustrate a case where a UE with a higher priority
(may be hereinafter referred to as a "UE 1") and a UE with a lower
priority (may be hereinafter referred to as a "UE 2") exist and a
beam via which the UE with a higher priority communicates is
different from a beam via which the UE with a lower priority
communicates.
[0608] In Step ST2801, the cell sets, to the UE 1, a PUCCH resource
configuration for each UE. In Step ST2801, the cell also sets, to
the UE 2, a PUCCH resource configuration for each UE.
[0609] In Step ST3101, the cell notifies the UE 1 of the
information on the PUCCH resources for each UE. The cell may notify
the information on the PUCCH resources via a beam via which the
cell communicates with the UE 1. The cell notifies the information
on the PUCCH resources via the RRC-dedicated signaling.
[0610] In Step ST3102, the cell notifies the UE 2 of the
information on the PUCCH resources for each UE. The cell may notify
the information on the PUCCH resources via a beam via which the
cell communicates with the UE 2. The cell notifies the information
on the PUCCH resources via the RRC-dedicated signaling.
[0611] Upon receipt of the information on the PUCCH resources for
each UE in Step ST3101, the UE 1 sets the PUCCH resource
configuration in Step ST3103.
[0612] Upon receipt of the information on the PUCCH resources for
each UE in Step ST3102, the UE 2 sets the PUCCH resource
configuration in Step ST3104.
[0613] In Step ST3105, the UE 1 determines whether the uplink data
has been generated. When the uplink data is not generated in Step
ST3105, the UE 1 returns to Step ST3105 to repeat the determination
on whether the uplink data has been generated. When the uplink data
has been generated in Step ST3105, the UE 1 proceeds to Step
ST3106.
[0614] In Step ST3106, the UE 1 transmits the SR to the cell via
the serving beam with the set PUCCH resource configuration for the
SR.
[0615] In Step ST3107, the cell recognizes a conflict between the
UE 1 and the UE 2 with the PUCCH resource timing.
[0616] In Step ST3108, the cell determines to receive, with the
PUCCH resource timing, the PUCCH via a beam via which the cell
communicates with the UE with a higher priority, here, the UE 1. In
other words, the cell determines not to receive, with the PUCCH
resource timing, the PUCCH via a beam via which the cell
communicates with the UE with a lower priority, here, the UE 2.
[0617] In Step ST3106, the cell receives, with the PUCCH resources
set to the UE 1, the SR transmitted from the UE 1.
[0618] Upon receipt of the SR from the UE 1, the cell starts, in
Step ST2510A, the uplink scheduling for the UE that has transmitted
the SR, that is, the UE 1.
[0619] In Step ST2511A, the cell transmits, to the UE 1, an uplink
grant, specifically, the uplink scheduling information including
the uplink grant.
[0620] Upon receipt of the uplink grant in Step ST2511A, the UE 1
transmits a Buffer Status Report (BSR) to the cell using the uplink
grant in Step ST2512A. Here, the UE 1 may transmit the uplink
data.
[0621] Upon receipt of the BSR in Step ST2512A, the cell performs
the uplink scheduling for the UE 1 according to the BSR.
[0622] In Step ST2513A, the cell transmits the uplink grant to the
UE 1. Upon receipt of the uplink grant in Step ST2513A, the UE 1
transmits the uplink data to the cell using the uplink grant in
Step ST2514A. In Step ST2514A, the cell receives the uplink data
transmitted from the UE 1.
[0623] As described above, the cell performs processes for starting
the uplink communication with the UE 1 from Steps ST2511A to
ST2514A. Consequently, the uplink communication is started between
the UE 1 and the cell.
[0624] In Step ST3109, the UE 2 determines whether the uplink data
has been generated. When the uplink data is not generated in Step
ST3109, the UE returns to Step ST3109 to repeat the determination
on whether the uplink data has been generated. When the uplink data
has been generated in Step ST3109, the UE proceeds to Step
ST3110.
[0625] In Step ST3110, the UE 2 transmits the SR to the cell via
the serving beam with the set PUCCH resource configuration for the
SR.
[0626] However, the cell determines in Step ST3108 to receive, with
the PUCCH resource timing, the PUCCH via the beam via which the
cell communicates with the UE 1.
[0627] Then in Step ST3108, the cell receives, with the PUCCH
resources set to the UE 1, the SR transmitted from the UE 1.
[0628] Thus, the cell cannot receive the SR transmitted from the UE
2 via the beam via which the cell communicates with the UE 2 in
Step ST3110.
[0629] In Step ST3111, the cell determines whether the BSR of the
UE 1 that is a UE with a higher priority is being received. When
the cell is not receiving the BSR in Step ST3111, the cell returns
to Step ST3111 to determine again whether the BSR is being
received. When the cell is receiving the BSR in Step ST3111, the
cell proceeds to Step ST3112.
[0630] When the cell is receiving the BSR in Step ST3111, the cell
determines that the UE 1 need not transmit the SR because the cell
is performing the process for scheduling the resources for
transmitting the uplink data to the UE 1. In Step ST3112, the cell
assigns the lowest priority to the UE 1.
[0631] In Step ST3113, the cell recognizes again a conflict between
the UE 1 and the UE 2 with the PUCCH resource timing.
[0632] In Step ST3114, the cell determines to receive, with the
PUCCH resource timing, the PUCCH via the beam via which the cell
communicates with the UE with a higher priority, here, the UE 2. In
other words, the cell determines not to receive, with the PUCCH
resource timing, the PUCCH via the beam via which the cell
communicates with the UE with a lower priority, here, the UE 1.
[0633] Although the UE 2 cannot receive the uplink grant in spite
of the transmission of the SR in Step ST3110, the UE 2 retransmits,
with the PUCCH resource timing, the SR to the cell via the serving
beam with the set PUCCH resource configuration for the SR in Step
ST3115.
[0634] In Step ST3115, the cell receives, with the PUCCH resources
set to the UE 2, the SR transmitted from the UE 2.
[0635] Upon receipt of the SR from the UE 2, the cell starts, in
Step ST2510A, the uplink scheduling for the UE that has transmitted
the SR, that is, the UE 2.
[0636] In Step ST2511B, the cell transmits, to the UE 2, an uplink
grant, specifically, the uplink scheduling information including
the uplink grant.
[0637] Upon receipt of the uplink grant in Step ST2511B, the UE 2
transmits the BSR to the cell using the uplink grant in Step
ST2512B. Here, the UE 2 may transmit the uplink data.
[0638] Upon receipt of the BSR in Step ST2512B, the cell performs
the uplink scheduling for the UE 2 according to the BSR.
[0639] In Step ST2513B, the cell transmits the uplink grant to the
UE 2. Upon receipt of the uplink grant in Step ST2513B, the UE 2
transmits the uplink data to the cell using the uplink grant in
Step ST2514B. In Step ST2514B, the cell receives the uplink data
transmitted from the UE 2.
[0640] As described above, the cell performs processes for starting
the uplink communication with the UE 2 from Steps ST2511B to
ST2514B. Consequently, the uplink communication is started between
the UE 2 and the cell.
[0641] Even when the PUCCH resource timings of a plurality of UEs
with different beams for communication conflict with each other,
the cell can receive the PUCCHs of the plurality of UEs.
[0642] Consequently, the conventional methods for setting the
PUCCHs can be applied regardless of the beams. Thus, it is possible
to avoid complexity in the processes that is caused by, for
example, addition of a process for the UE. Reassigning the lowest
priority to the UE to which the cell has transmitted the uplink
grant enables reception of the PUCCH from the UE with a lower
priority via the beam. Thus, it is possible to avoid increase in
the power consumption and increase in the uplink interference power
due to repetition of unnecessary transmission of the PUCCH from the
UE with a lower priority.
Fourth Embodiment
[0643] The second to the third embodiments disclose allocating
symbols as the smallest unit of resources to which the PUCCH is
allocated. As the number of times the beam sweeping is performed
increases, the number of symbols necessary for the PUCCH resources
also increases. Thus, configuring the PUCCH resources for many
beams within one subframe will cause problems of reduction in the
resources for data and decrease in the communication rate.
Alternatively, configuring the PUCCH resources for fewer beams
within one subframe requires the PUCCH resources over a plurality
of subframes, and increases intervals at which the PUCCH resources
for each beam are generated. These create a problem of increase in
the latency.
[0644] The fourth embodiment will disclose a method for solving
such problems.
[0645] A plurality of symbols are configured within one symbol
duration, and the PUCCH resources of a plurality of beams are
time-division multiplexed. The number of the plurality of symbols
to be configured within one symbol duration may be 2.sup.n times (n
is a natural number). Consequently, the symbol duration during
which the PUCCH resources are allocated can be shortened, and the
PUCCH resources for many beams can be configured. The symbol that
has been shortened may be referred to as a shortened symbol in the
following description.
[0646] Larger subcarrier spacing (see 3GPP R1-166566 (hereinafter
referred to as "Reference 7")) approach proposed by 3GPP may be
applied as a method for configuring a plurality of symbols within
one symbol duration. Reference 7 discloses that four symbols are
configured within one symbol duration and that the UE performs
transmission using the four symbols by sweeping beams in each of
the symbols. Reference 7 also discloses that the cell receives
transmission from one UE in the four symbols.
[0647] According to the fourth embodiment, each shortened symbol is
allocated as a PUCCH resource for each UE. Upon receipt of a
plurality of shortened symbols configured within one symbol
duration, the cell can receive the PUCCHs from a plurality of UEs
communicating via different beams.
[0648] Shortening one symbol duration widens the subcarrier
spacing. Since the MBF requiring the beam sweeping does not allow
transmission and reception with the same timing via a plurality of
beams, the time-division multiplexing is necessary. Conversely,
since the transmission and reception can be performed with a given
timing only via a beam in a specific direction, the frequency
resources over the entire bandwidth can be used with the timing.
Even when the subcarrier spacing is widened and the required
frequency resources increase, it is effective to shorten one symbol
duration and allocate the one symbol duration to the PUCCHs for a
plurality of beams.
[0649] Although disclosed is configuring, within one symbol
duration, 2.sup.n times of the symbols according to the
aforementioned method, the duration may not include one symbol but
a plurality of symbols. Each of the plurality of symbols may have
2.sup.n times of the symbols within one symbol duration. The value
n may be consistent among the symbols, or different in each of the
symbols.
[0650] Consequently, the PUCCH resources for many more beams can be
allocated to the shortened symbols.
[0651] A method for setting the resources for the PUCCH will be
disclosed. Besides the information on the PUCCH resources disclosed
in the second embodiment, information on the shortened symbols is
provided.
[0652] The following (1) to (6) will be disclosed as specific
examples of the information on the shortened symbols:
[0653] (1) a symbol number of a symbol to be a shortened
symbol;
[0654] (2) the number of the shortened symbols to be configured in
one symbol;
[0655] (3) a symbol length of a shortened symbol;
[0656] (4) a subcarrier spacing of a shortened symbol;
[0657] (5) a symbol number of a shortened symbol: and
[0658] (6) combinations of (1) to (5) above.
[0659] The cell notifies the UE of the information on the shortened
symbols. The cell may notify the UE of the information on the PUCCH
resources. The cell may notify the UE of the information on the
shortened symbols and the information on the PUCCH resources in
combination.
[0660] The cell may notify the UE of the information on the
shortened symbols together with the information on the
corresponding PUCCH resources, or include the information on the
shortened symbols in the information on the corresponding PUCCH
resources to notify the information on the shortened symbols.
[0661] The PUCCH resources may be set not only to the shortened
symbols but to normal symbols that are not the shortened symbols.
Here, the information on the PUCCH resources for the normal symbols
may be provided separately from the information on the PUCCH
resources for the shortened symbols.
[0662] The methods according to the second to the third embodiments
may be appropriately applied to a method for allocating the
resources for the PUCCH. The methods disclosed in each of the
embodiments and the modifications may be applied to a method for
notifying the information on the shortened symbols or the
information on the corresponding PUCCH resources.
[0663] Consequently, the PUCCH resources for many more beams can be
configured within one subframe for the cell or the TRP requiring
the beam sweeping a large number of times. This can suppress
decrease in the communication rate due to decrease in the resources
for data, and increase in the latency due to increase in the
intervals at which the PUCCH resources for each beam are
generated.
[0664] Since the UE transmits the PUCCH in the shortened symbol,
the UE can shorten the time to transmit the PUCCH. Consequently,
the power consumption of the UE and the uplink interference power
can be reduced.
[0665] The cell may separately use the normal symbols and the
shortened symbols. The cell may determine whether to use the normal
symbols or the shortened symbols, for example, according to the
number of times the beam sweeping is performed. When the number of
times the beam sweeping is performed is many, the cell may
configure the shortened symbols. Consequently, when the number of
times the beam sweeping is performed is less, the shortened symbols
are unnecessary. Thus, the settings and the processes in the cell
and the UE can be facilitated.
[0666] The cell may determine whether to use the normal symbols or
the shortened symbols, for another example, according to the number
of UEs communicating with each of the beams. The shortened symbols
are configured for and allocated to the beams with a few number of
UEs for communication. The normal symbols are allocated to the
beams with a large number of UEs for communication. The shortened
symbols increase the subcarrier spacing. Consequently, the number
of UEs that can be multiplexed with one shortened symbol decreases
more than that using the normal symbol. Thus, it is effective to
allocate the normal symbols to the beams with a large number of UEs
for communication.
[0667] Separately using the normal symbols and the shortened
symbols can increase the use efficiency of the radio resources
according to, for example, the beam structure and a load of each
beam.
First Modification of Fourth Embodiment
[0668] The fourth embodiment discloses a method for solving the
problem of increase in the number of symbols necessary for the
PUCCH resources as, for example, the number of times the beam
sweeping is performed increases.
[0669] The first modification will disclose another method for
solving such a problem.
[0670] One symbol duration is divided into a predefined number. In
the following description, a duration obtained by dividing the one
symbol duration by the predefined number may be referred to as a
divided duration. The predefined number is denoted by n. The UE
multiplies the PUCCH data timing within one symbol by n, and
repeats the PUCCH data within the one symbol n times. The UE
transmits the PUCCH in this manner. The cell shortens intervals at
which the beams are switched. The cell switches between the beams
for a divided duration of 1/n obtained by dividing one symbol
duration to receive the PUCCH.
[0671] The UE transmits the PUCCH for one symbol duration via a
beam via which the UE communicates, whereas the cell receives the
PUCCH for the divided duration via the beam. The cell receives the
PUCCH transmitted from the UE via a plurality of beams, for the
divided duration via each of the beams. Consequently, the cell can
receive, for the divided duration, the PUCCH transmitted for one
symbol duration via a plurality of beams.
[0672] Interleaved Frequency Domain Multiple Access (IFDMA) based
approach (see "Reference 7") proposed by 3GPP may be applied as a
method for multiplying the PUCCH data timing within one symbol by n
and repeating the PUCCH data within the one symbol n times.
Reference 7 discloses multiplying the data timing within one symbol
by four and repeating the data within the one symbol four
times.
[0673] Reference 7 discloses a case where in one symbol, one UE
repeats data and switches between beams for each data to transmit
the data. The cell receives the data via the same beams for one
symbol duration. Although one UE repeats data in one symbol n times
in the first modification, it never switches between beams. The
cell switches between the beams for a divided duration of 1/n
obtained by dividing one symbol duration to receive the data. The
cell receives one piece of the data repeated n times.
[0674] Subcarriers are discretely used at n intervals to accelerate
the data timing n times. Transmitting data using seemingly n times
as many sub-carriers can accelerate the data timing n times. Since
the data timing is accelerated n times within one symbol duration,
the same data is repeated n times. Cyclic Prefix (CP) may be added
to the beginning of one symbol. Alternatively, CP may be added to
the end of one symbol. Alternatively, CP may be added to both the
beginning and the end of one symbol. The cell and the UE may
mutually recognize the CP.
[0675] The UE repeatedly transmits data for PUCCH n times in a
symbol set for the PUCCH resources for one symbol duration. UEs
with different beams each repeatedly transmit the data for PUCCH n
times in a symbol set for the PUCCH resources for one symbol
duration. Here, the UEs with different beams may transmit the data
for PUCCH in the same symbol.
[0676] The cell switches between the beams for a divided duration
of 1/n obtained by dividing one symbol duration to receive the
data. The cell receives one piece of the data for PUCCH to be
transmitted from the UE with each beam and repeated n times.
Consequently, the PUCCH resources for many more beams can be
allocated to one symbol. Moreover, discrete Fourier transform
spread (DFT-s)-OFDM can be used. Thus, an uplink Peak-to-Average
Power Ratio (PAPR) of the UE and the power consumption of the UE
can be reduced.
[0677] A method for setting the resources for the PUCCH will be
disclosed. Besides the information on the PUCCH resources disclosed
in the second embodiment, information on the divided duration is
provided.
[0678] The following (1) to (7) will be disclosed as specific
examples of the information on the divided duration:
[0679] (1) the number of divisions in one symbol;
[0680] (2) how many times a frequency range is increased;
[0681] (3) frequency resources;
[0682] (4) the number of times data is repeated;
[0683] (5) a method for inserting the CP;
[0684] (6) the position into which the CP is inserted; and
[0685] (7) combinations of (1) to (6) above.
[0686] The cell notifies the UE of the information on the divided
duration. The cell may notify the UE of the information on the
PUCCH resources. The cell may notify the UE of the information on
the divided duration and the information on the PUCCH resources in
combination.
[0687] The cell may notify the UE of the information on the divided
duration together with the information on the corresponding PUCCH
resources, or include the information on the divided duration in
the information on the corresponding PUCCH resources to notify the
information on the divided duration.
[0688] The PUCCH resources may be set not only to the divided
duration but to normal symbols that are not divided. Here, the
information on the PUCCH resources for the normal symbols may be
provided separately from the information on the PUCCH resources for
the divided symbols.
[0689] The methods according to the second to the third embodiments
may be appropriately applied to a method for allocating the
resources for the PUCCH. The methods disclosed in each of the
embodiments and the modifications may be applied to a method for
notifying the information on the divided duration or the
information on the corresponding PUCCH resources.
[0690] Consequently, the PUCCH resources for many more beams can be
configured within one subframe for the cell or the TRP requiring
the beam sweeping a large number of times. This can suppress
decrease in the communication rate due to decrease in the resources
for data, and increase in the latency due to increase in the
intervals at which the PUCCH resources for each beam are
generated.
[0691] The cell may separately use the normal symbols and the
divided symbols. The methods disclosed in the fourth embodiment may
be applied thereto. Consequently, the use efficiency of the radio
resources can be increased according to, for example, the beam
structure and a load of each beam.
Fifth Embodiment
[0692] Upon receipt of the SR, the cell transmits an uplink grant
as a response signal for the SR. 3GPP has never discussed the
transmission timing of the uplink grant for the SR in the MBF
requiring the beam sweeping. When the beam sweeping is required,
the timing of each beam is limited. Thus, the cell and the UE need
to mutually recognize the transmission timing of the uplink grant
for the SR.
[0693] The fifth embodiment will disclose the
transmission/reception timing of a response signal to the SR.
[0694] After the UE transmits the SR, the cell receiving the SR
makes the timing to transmit the uplink grant to the UE
asynchronous. The cell transmits the uplink grant for the SR to the
UE with an arbitrary timing via a serving beam of the UE via which
the SR has been transmitted. After transmitting the SR, the UE
receives the L1/L2 control signal in each subframe.
[0695] Even when the cell performs transmission and reception via
the other beams from receipt of the SR to the transmission timing
of the uplink grant, the UE receives the L1/L2 control signal in
each subframe. In the case where the cell performs transmission and
reception via the other beams, the UE can determine the absence of
the uplink grant because the UE cannot receive the L1/L2 control
signal. Consequently, the UE can receive the uplink grant
transmitted with an arbitrary timing.
[0696] The cell determines the timing to transmit the uplink grant
for the SR via the beam via which the SR has been received. The
examples of the judgment indicators for allocating the PUCCH
resources that are disclosed in the second embodiment may be
applied to examples of a judgment indicator for the
determination.
[0697] As such, making the timing to transmit the uplink grant for
the SR asynchronous enables the cell to determine the timing to
transmit the uplink grant according to a state indicated by the
judgment indicator. Even when the timing is asynchronous, the UE
can receive the uplink grant for the transmitted SR, and start the
uplink communication.
[0698] Another method on the transmission/reception timing of the
uplink grant for the SR will be disclosed.
[0699] When the timing to transmit the uplink grant for the SR is
made asynchronous, the UE has to receive the L1/L2 control signal
in each subframe after transmitting the SR. However, since the MBF
requiring the beam sweeping has the timing to perform transmission
and reception via the other beams, a problem for the UE to perform
unnecessary reception in each subframe occurs.
[0700] A method for solving such a problem will be disclosed.
[0701] Assume N+L as the transmission timing of the uplink grant
for the SR. Here, N denotes the SR transmission timing. L denotes
one value larger than or equal to 0. N and L may be represented per
scheduling. Examples of the unit of scheduling include per
subframe, per slot, and per mini-slot.
[0702] Consequently, the UE need not receive the L1/L2 control
signal in each subframe. Thus, the power consumption of the UE can
be reduced due to no unnecessary reception operation.
[0703] Another method will be disclosed.
[0704] In the method previously disclosed, L denotes one value. L
may denote a plurality of values. The cell sets, to the UE, a
plurality of timings for the SR, for example, L1, L2, L3, . . . .
The maximum value for the number of Ls may be determined.
[0705] A range (duration) for setting the value L may be
determined. The range (duration) for setting the value L is denoted
by, for example, K. For example, when the unit of scheduling is per
subframe, the value L is set within K subframes. After a lapse of
the K subframes, the setting for a duration denoted by K may be
further repeated. For example, K=6 and L=1, 3 are set.
[0706] N may be a starting point as a starting point for the
duration denoted by K. Alternatively, an offset value may be
provided, and a point after the offset from N may be set as a
starting point.
[0707] When N is the starting point in the aforementioned example,
the setting of L=1, 3 is repeated every 6 subframes with respect to
N as the starting point.
[0708] The transmission timing of the uplink grant for the SR is
set to the (L+1)-th subframe from the first subframe during a
duration from subframe (N+0) to subframe N+(K-1) with respect to N
as the starting point.
[0709] Here, the transmission timing of the uplink grant for the SR
is set in the (N+1)-th and the (N+3)-th subframes. After a lapse of
K=6, the setting for the duration denoted by K may be further
repeated.
[0710] The setting of a plurality of values enables the cell to
select the transmission timing of the uplink grant for the SR. The
cell does not have to transmit the uplink grant with all the set
plurality of timings. The cell may transmit and receive the other
beams. The cell can determine the transmission timing of the uplink
grant for the SR according to a state for each beam.
[0711] The UE receives the L1/L2 control signal with the set
plurality of timings.
[0712] Consequently, the power consumption of the UE can be more
reduced and the transmission timing can be more appropriate for a
state of the cell than those when the transmission timing is made
asynchronous. This can increase the use efficiency of the radio
resources of the cell.
[0713] Another method will be disclosed.
[0714] The value L may be set differently between odd and even
numbers. When L is an even number (may include 0), the transmission
timing of the uplink grant for the SR is generated in the
even-numbered subframe with respect to N as a starting point. When
L is an odd number, the transmission timing of the uplink grant for
the SR is generated in the odd-numbered subframe with respect to N
as a starting point.
[0715] The cell selects the set N+L transmission timings, and
transmits the uplink grant for the SR. The cell does not have to
transmit the uplink grant with all the N+L transmission timings.
The cell may transmit and receive the other beams. The cell can
determine the transmission timing of the uplink grant for the SR
according to a state for each beam.
[0716] The UE receives the L1/L2 control signal with the N+L
transmission timings according to L set to either an odd number or
an even number. Consequently, the power consumption of the UE can
be half and the transmission timing can be more appropriate for a
state of the cell than those when the transmission timing is made
asynchronous. This can increase the use efficiency of the radio
resources of the cell.
[0717] Although disclosed is setting L to either an odd number or
an even number, the setting may be made similarly using a remainder
of A. A is an integer larger than or equal to 1. Lis set to 0, 1,
2, . . . , or (A-1). For example, when A=6, Lis set to 0, 1, 2, 3,
4, or 5.
[0718] Here, the transmission timings denoted by
N+(A.times.(n-1)+L) are generated.
[0719] The cell selects the set transmission timings, and transmits
the uplink grant for the SR. The cell does not have to transmit the
uplink grant with all the set transmission timings. The cell may
transmit and receive the other beams. The cell can determine the
transmission timing of the uplink grant for the SR according to a
state for each beam.
[0720] The UE receives the L1/L2 control signal with the set
timings according to the set L. Consequently, the power consumption
of the UE can be half and the transmission timing can be more
appropriate for a state of the cell than those when the
transmission timing is made asynchronous. This can increase the use
efficiency of the radio resources of the cell.
[0721] Although disclosed is setting with the timing with respect
to N as the starting point, the setting may be made by a subframe
number given in the cell. This is effective when a subframe number
is given to indicate via which beam transmission and reception is
performed.
[0722] Another method will be disclosed.
[0723] A duration during which the uplink grant for the SR is not
transmitted may be set to L. The cell transmits the uplink grant
for the SR with an arbitrary timing later than N+L. The UE receives
the L1/L2 control signal with the timing later than N+L.
[0724] For example, assume the processing time by the cell as n,
the setting when L>n is made. Here, the cell does not transmit
the uplink grant for the SR with the timing from N to N+L. The cell
transmits the uplink grant for the SR with an arbitrary timing
later than N+L. The UE does not receive the L1/L2 control signal
with the timing from N to N+L. The UE receives the L1/L2 control
signal with the timing later than N+L.
[0725] When the unit of scheduling is per subframe, the cell does
not transmit the uplink grant for the SR in subframes from N to
N+L. The cell transmits the uplink grant for the SR in arbitrary
subframes later than N+L. The UE does not receive the L1/L2 control
signal in the subframes from N to N+L. The UE receives the L1/L2
control signal in each subframe later than N+L.
[0726] Consequently, the UE does not have to receive the L1/L2
control signal in some subframes after transmitting the SR.
[0727] Moreover, a reception duration later than N+L may be set.
The reception duration is denoted by W. The cell transmits the
uplink grant for the SR with an arbitrary timing for a duration
denoted by W later than N+L. The UE receives the L1/L2 control
signal with the timing for the duration denoted by W later than
N+L.
[0728] Consequently, the UE does not have to receive the L1/L2
control signal in some subframes after transmitting the SR. The UE
has only to receive the L1/L2 control signal for the duration
denoted by W later than N+L. Thus, the power consumption of the UE
can be reduced.
[0729] Consequently, the cell can make the transmission timing more
appropriate for a state of the cell while reducing the power
consumption of the UE. This can increase the use efficiency of the
radio resources of the cell.
[0730] Another method will be disclosed.
[0731] The method is to follow the timing to perform the downlink
scheduling for the UE when the timing is predetermined. The UE
receives the L1/L2 control signal with the timing to perform the
downlink scheduling subsequent to the transmission of the SR. The
methods disclosed in the first embodiment may be applied to a
method for presetting the timing to perform the downlink scheduling
to the UE.
[0732] This enables application of a method consistent not only
with that for the uplink grant for the SR but also with that for
the normal scheduling. Thus, processes in the cell and the UE can
be facilitated.
[0733] Among the methods previously disclosed, methods for the cell
to set information (may be hereinafter referred to as "information
on an SR response") to the UE and notify the UE of the information
will be disclosed.
[0734] The methods may be fixed in a system. The methods may be
statically predetermined in, for example, a standard.
[0735] As an alternative method, the setting may be made for at
least one of each cell and each beam. The method for the cell to
notify the UE of the information may be the same as the method for
notifying the information on the PUCCH resources for each beam that
is disclosed in the second embodiment. For example, the information
for each cell may be included in the system information to be
broadcast, or included in an RRC message to be notified
individually to each UE.
[0736] As an alternative method, the setting may be made for each
UE. The method for the cell to notify the UE of the information may
be the same as the method for notifying the information on the
PUCCH resources for each UE that is disclosed in the second
embodiment. For example, the information for each UE may be
included in the RRC message to be notified individually to each
UE.
[0737] These setting and notification methods may be performed in
combination. These methods may be separately used for each piece of
the information on the SR response. For example, when a remainder
is used, A is fixed in a system, and L is set for each UE, etc.
Alternatively, K is set for each cell, and L is set for each beam,
etc. Consequently, the cell can notify the UE of the timing with
which the uplink grant for the SR is to be generated.
[0738] Another method will be disclosed.
[0739] The cell and the UE derive the timing to transmit the uplink
grant for the SR, using a UE identifier of the UE that has
transmitted the SR. For example, when N+L denotes the timing to
transmit the uplink grant for the SR, the cell and the UE derive L
using an identifier of the UE that has transmitted the SR. For
example, when the identifier of the UE is odd, the cell and the UE
determine L to be odd. For example, when the identifier of the UE
is even, the cell and the UE determine L to be even.
[0740] An identifier of a beam may be used instead of the
identifier of the UE. The cell and the UE derive the timing to
transmit the uplink grant for the SR, using an identifier of the
beam via which the UE that has transmitted the SR is communicating.
For example, when N+L denotes the timing to transmit the uplink
grant for the SR, the cell and the UE derive L using the identifier
of the beam via which the UE that has transmitted the SR is
communicating. For example, when the identifier of the beam is odd,
the cell and the UE determine L to be odd. For example, when the
identifier of the beam is even, the cell and the UE determine L to
be even.
[0741] Consequently, the cell does not have to set the information
on the SR response to the UE. This can reduce the signaling
load.
[0742] FIG. 24 illustrates one example sequence for setting the
transmission/reception timing of the uplink grant for the SR. Since
the sequence illustrated in FIG. 24 includes the same Steps as
those in the sequence illustrated in FIG. 19, the same step numbers
will be assigned to the same Steps and the common description
thereof will be omitted.
[0743] In Step ST2801, the cell sets, to the UE, a PUCCH resource
configuration for each UE.
[0744] In Step ST3201, the cell sets, to the UE, an SR response
timing for the UE.
[0745] In Step ST3202, the cell notifies the UE of the information
on the SR response together with the information on the PUCCH
resources. The cell may notify the information on the PUCCH
resources and the information on the SR response via a beam via
which the cell communicates with the UE. The cell notifies the
information on the PUCCH resources and the information on the SR
response via the RRC-dedicated signaling.
[0746] After performing the process in Step ST3202, the cell
performs the processes in Steps ST2804, ST2805, and ST2806.
[0747] Upon receipt of the information on the PUCCH resources and
the information on the SR response in Step ST3202, the UE performs
the process in Step ST2803. Then, the UE performs the process in
Step ST2813.
[0748] In Step ST2811, the UE determines whether the uplink data
has been generated. When the uplink data has been generated, the UE
proceeds to Step ST2812A.
[0749] In Step ST2812A, the UE transmits the SR to the cell via the
serving beam with the set PUCCH resource configuration for the
SR.
[0750] Upon receipt of the SR from the UE in Step ST2812A, the cell
performs the uplink scheduling with the SR response timing set to
the UE in Step ST3203.
[0751] Upon transmission of the SR in Step ST2812A, the UE derives
the SR response timing using the information on the SR response,
and performs reception with the SR response timing in Step
ST3204.
[0752] In Step ST2511, the cell notifies the UE of the uplink grant
with the set SR response timing.
[0753] In Step ST2511, the UE obtains the uplink grant from the
cell with the set SR response timing.
[0754] Upon receipt of the uplink grant for the SR from the cell,
the UE performs processes for starting the uplink communication
with the cell from Steps ST2512 to ST2514. Consequently, the uplink
communication is started between the UE and the cell.
[0755] Application of the methods disclosed in the fifth embodiment
enables the cell to notify the UE of the information on the SR
response, and the cell and the UE to mutually recognize the
transmission timing of the uplink grant for the SR.
Sixth Embodiment
[0756] When the transmission of the SR is undelivered, the cell
does not transmit the uplink grant for the SR to the UE.
Alternatively, even when the cell transmits the uplink grant to the
UE, the UE may not be able to receive the uplink grant due to the
worse radio propagation environment. In these cases, the UE cannot
determine whether the cell does not transmit the uplink grant due
to the undelivered transmission of the SR, or whether the cell
cannot communicate via the serving beam while communicating via
another beam and thus does not transmit the uplink grant for the
SR.
[0757] Since the UE receives the uplink grant for the SR with the
SR response timing, the UE continues to receive the L1/L2 control
signal. 3GPP has never discussed the undelivered transmission of
the SR in the MBF requiring the beam sweeping.
[0758] The sixth embodiment will disclose a method for solving such
a problem.
[0759] A timer for setting a duration from transmission of the SR
to wait for the uplink grant is provided. In the following
description, the timer may be referred to as an "SR-response wait
timer". Upon transmission of the SR, the UE starts the SR-response
wait timer. Upon receipt of the uplink grant before expiration of
the SR-response wait timer, the UE resets the SR-response wait
timer. When the UE cannot receive the uplink grant during the
duration of the SR-response wait timer and the SR-response wait
timer expires, the UE retransmits the SR.
[0760] The value of the SR-response wait timer may be predetermined
in, for example, a standard. Alternatively, the cell may set the
value of the SR-response wait timer, and notify it to the UE. The
method for notifying the information on the SR response that is
disclosed in the fifth embodiment may be applied thereto. The
SR-response wait timer may be set per time unit or per scheduling.
Examples of the unit of scheduling include subframe, slot, and
mini-slot.
[0761] Consequently, it is possible for the UE to assume that the
cell transmits the uplink grant for the SR during the duration of
the SR-response wait timer upon transmission of the SR. When the
SR-response wait timer expires, the UE can retransmit the SR
because the transmission of the SR is undelivered. Thus, the UE,
which cannot determine whether the cell is communicating via
another beam, never continues to receive the L1/L2 control signal
with the SR response timing.
[0762] The SR response timing may be set for each beam or for each
UE. Thus, the SR response timing may be different for each beam or
for each UE. When the value of the SR-response wait timer is set as
a duration from the transmission of the SR, a different value needs
to be set for each beam or for each UE, which will cause a problem
of complexity in the setting.
[0763] A method for solving such a problem will be disclosed.
[0764] The SR-response wait timer is set to the number of
transmission timings of the uplink grant for the SR. The
SR-response wait timer is set to, for example, X times. When
starting the SR-response wait timer upon transmission of the SR and
receiving the uplink grant within the X transmission timings of the
uplink grant for the SR, the UE resets the SR-response wait timer.
When the UE does not receive the uplink grant within the X
transmission timings of the uplink grant for the SR, the UE
retransmits the SR.
[0765] When a range for setting the value L (K) is determined in
the setting of the transmission timing of the uplink grant for the
SR that is disclosed in the fifth embodiment, the SR-response wait
timer may be set to the number of repetitions of K. The SR-response
wait timer is set to, for example, X times. When the UE starts the
SR-response wait timer upon transmission of the SR and receives the
uplink grant while the number of repetitions of K falls within the
X times, the UE resets the SR-response wait timer. When the UE does
not receive the uplink grant while the number of repetitions of K
falls within the X times, the UE retransmits the SR.
[0766] Consequently, the SR-response wait timer can be set
according to the number of times the uplink grant is generated.
Thus, when the SR-response wait timer is set with equal
opportunities for each beam or for each UE according to the number
of times the uplink grant is generated, the setting need not be
made using a different timer value. Consequently, the cell can
easily perform the processes of setting the SR-response wait timer
to the UE and notifying the UE of the setting.
[0767] When the UE cannot receive the uplink grant for the SR from
the cell according to the aforementioned method, the UE continues
to retransmit the SR. For example, when the UE is out of the uplink
synchronization via the beam via which the UE communicates, the
cell cannot receive the SR transmitted from the UE. No matter how
many times the UE retransmits the SR in such a continued state, the
cell can neither receive the SR transmitted from the UE, nor
transmits the uplink grant for the SR. Thus, the UE repeats
retransmission of the SR.
[0768] A method for solving such a problem will be disclosed.
[0769] The maximum number of times the SR is retransmitted may be
provided. The maximum number of times is set to, for example, Y
times. When the number of times the UE retransmits the SR exceeds Y
times, the UE stops retransmitting the SR. Consequently, the UE can
avoid continuing to retransmit the SR due to, for example, the
movement of the UE and the worse radio propagation environment.
Thus, the power consumption of the UE can be reduced.
[0770] When the number of times the UE retransmits the SR exceeds Y
times, the UE may start from the RA procedure. The RA procedure
initiates the uplink synchronization. The beam sweeping block may
be used for the RA procedure. Consequently, the UE can again
achieve the uplink synchronization via the beam via which the UE
communicates.
[0771] When the number of times the UE retransmits the SR exceeds Y
times, the settings for the PUCCH resources, the SR response, and
the undelivered SR that are made for the UE may be reset. Since the
reset can release the set resources to the others, the use
efficiency of the radio resources can be increased.
Seventh Embodiment
[0772] A beam coverage in the MBF is narrower than a coverage of
the cell. When the beam sweeping is necessary in the MBF, the cell
may communicate via the other beams while the UE transmits the SR
and receives the uplink grant for the SR. Here, the duration from
the transmission of the SR to the reception timing of the SR
response signal is longer than that when the beam sweeping is
unnecessary.
[0773] Thus, while transmitting the SR and receiving the SR
response signal, the UE may move across beam coverages. In other
words, the UE may move (have mobility) between beams. The cell
configures one or more TRPs, and each of the TRPs forms one or more
beams. Although the movement between beams will be mainly described
herein, the description is applicable to the movement between
TRPs.
[0774] The description may be applied to the movement between beams
formed by the TRP. A Distributed Unit (DU) may form one or more
beams. Here, the description is applicable to the movement between
DUs. The description may be applied to the movement between beams
formed by the DUs.
[0775] The fifth embodiment discloses a method for setting the
timing to receive the SR response signal via the beam via which the
UE has transmitted the SR. However, when the UE moves between beams
after transmitting the SR, the method according to the fifth
embodiment cannot be simply applied thereto because the UE moves
from the beam via which the UE has transmitted the SR. Under such a
state, how to transmit and receive the SR response signal between
the cell and UE will be a problem.
[0776] The seventh embodiment will disclose a method for solving
such a problem.
[0777] In the case where the UE moves between beams after
transmitting the SR, even when the UE waits for the uplink grant
for the SR via the same beam via which the UE has transmitted the
SR, the communication quality of the UE via the beam will worsen.
Thus, the UE may not be able to receive the uplink grant. The
seventh embodiment will disclose a method for solving such a
problem.
[0778] The UE receives the uplink grant in response to the
transmitted SR via a moving target beam, when the UE moves between
beams after transmitting the SR. After receiving the SR from the
UE, the cell transmits the uplink grant in response to the received
SR to the UE via the moving target beam of the UE. Consequently,
the SR response signal can be transmitted and received via a beam
with superior communication quality for the UE. Thus, the reception
error rate of the SR response signal in the UE can be reduced.
[0779] The transmission timing of the uplink grant for the SR will
be disclosed.
[0780] When the cell transmits, via a moving target beam, the
uplink grant for the SR transmitted via a moving source beam, the
setting of the transmission timing of the uplink grant via the
moving target beam will be a problem because the beams are
different. Examples of the problem include whether the setting of
the moving source beam (may be hereinafter referred to as a "source
beam (S-beam)") is used as it is, whether the new setting of the
moving target beam (may be hereinafter referred to as a "target
beam (T-beam)") will be made, and how to make the new setting if
the new setting is made.
[0781] The seventh embodiment will disclose a method for solving
such a problem.
[0782] When the transmission timing of the uplink grant for the SR
is fixed in a system or is set equal for each cell via all the
beams in the cell, the UE may follow the setting after moving
between the beams. The transmission timing of the SR may be used as
the starting point. The transmission timing of the uplink grant for
the SR may also be set equal among a plurality of beams in the
cell. The transmission timing of the SR may be used as the starting
point to obtain the transmission timing of the uplink grant for the
SR.
[0783] To address the sudden worsening of the radio propagation
situation, a proposal is made for the UE to receive physical
control channels of a plurality of beams. Such a plurality of beams
may form a beam group. The UE may set, as a beam group, the moving
target beams due to the sudden worsening of the radio propagation
situation of a beam via which the UE is communicating. For example,
the transmission timing of the uplink grant for the SR may be set
equal in the beam group.
[0784] Consequently, the UE can receive the SR response signal via
the target beam after moving between the beams. Since the UE does
not change the reception timing of the SR response signal even
after moving between the beams, the UE can easily perform the
processes of moving between the beams.
[0785] Although using the transmission timing of the SR as the
starting point to obtain the transmission timing of the SR response
signal is disclosed, the timing of the SR response signal may be
determined using the timing of the UE to move between beams or the
timing for the cell to instruct the UE to move between beams as an
alternative method.
[0786] Consequently, the need for the SR transmission timing via
the source beam can be eliminated for the target beam. Moreover,
since the timing of an instruction for moving between beams is used
as the starting point, new information need not be informed. Thus,
the processes required for the UE and between the beams can be
facilitated.
[0787] A method to be applied when the transmission timing of the
uplink grant for the SR is set for each beam or for each UE and
each beam will be disclosed. When the transmission timing is set
for each beam, the cell presets, to the UE, the transmission
timings of the uplink grant for the SR via all the beams or a
plurality of beams in the cell. When the transmission timing is set
for each beam and each UE, the cell presets, to the UE, the
transmission timings of the uplink grant for the SR for each UE via
the target beam or a plurality of beams.
[0788] The plurality of beams may form the beam group. The
plurality of beams may form a group of a plurality of beams that
may be target beams.
[0789] After moving between beams, the UE performs reception with
the transmission timing of the uplink grant for the SR via a target
beam. After the UE moves between beams, the cell performs
transmission with the transmission timing of the uplink grant for
the SR via the target beam.
[0790] Consequently, the UE can receive the SR response signal via
the target beam after moving between the beams.
[0791] When the cell notifies the UE of a moving instruction for
the UE to move between beams, the UE may perform reception with the
transmission timing of the uplink grant for the SR via a target
beam after receiving the moving instruction for moving between
beams from the cell. After transmitting the moving instruction for
moving between beams to the UE, the cell may perform transmission
with the transmission timing of the uplink grant for the SR via the
target beam.
[0792] When the transmission timing of the SR is used as the
starting point to obtain the transmission timing of the uplink
grant for the SR, the transmission timing of the SR via the source
beam may be used as the starting point. Consequently, the cell and
the UE can determine the transmission timing of the uplink grant
for the SR. Upon reception with the transmission timing, the UE can
receive the SR response signal transmitted by the cell with the
transmission timing.
[0793] When a duration from the transmission timing of the SR via a
target beam to the reception timing of the SR response signal is
longer than a duration from the transmission timing of the SR via a
source beam to the reception timing of the SR response signal, the
reception timing of the SR response signal via the target beam may
end before the UE moves between the beams. If the cell transmits
the uplink grant with the transmission timing of the SR response
signal via the target beam, the UE cannot receive the uplink grant
for the SR.
[0794] A method for solving such a problem will be disclosed.
[0795] With regard to the transmission timing of the uplink grant
for the SR, the UE follows the transmission timing of the uplink
grant for the SR via a source beam when the UE moves between beams.
When the UE that has transmitted the SR receives the moving
instruction before receiving the uplink grant for the SR, the UE
performs reception with the transmission timing of the uplink grant
set via the source beam, using the transmission timing of the SR
via the source beam as the starting point.
[0796] When instructing the UE that has transmitted the SR to move
between the beams before transmitting the uplink grant for the SR,
the cell transmits the transmission timing of the uplink grant for
the SR to the UE with the transmission timing of the uplink grant
set via the source beam, using the transmission timing of the SR
via the source beam as the starting point. Since the timing of the
SR response signal can be set to the transmission timing of the
uplink grant for the SR via the source beam even when the UE moves
between the beams, the reception timing of the SR response signal
never ends before the UE moves between the beams, and the UE can
receive the SR response signal via the target beam.
[0797] Another method will be disclosed.
[0798] With regard to the transmission timing of the uplink grant
for the SR, the cell follows a longer duration from transmission of
the SR to the transmission timing of the uplink grant for the SR
when the UE moves between beams. The cell presets, to the UE, the
reception timings of the SR response signal via all the beams or a
plurality of beams in the cell. The plurality of beams may form the
beam group.
[0799] When the UE that has transmitted the SR receives the moving
instruction before receiving the uplink grant for the SR, the UE
compares a duration from transmission of the SR via the source beam
to the reception timing of the uplink grant for the SR with a
duration from transmission of the SR via the target beam to the
reception timing of the uplink grant for the SR, selects and sets
the reception timing of the uplink grant for the SR in the longer
duration, and performs reception with the reception timing.
[0800] When the cell transmits the instruction for moving between
beams to the UE that has transmitted the SR, before transmitting
the uplink grant for the SR, the cell compares a duration from
transmission of the SR via the source beam to the transmission
timing of the uplink grant for the SR with a duration from
transmission of the SR via the target beam to the transmission
timing of the uplink grant for the SR, selects and sets the
transmission timing of the uplink grant for the SR in the longer
duration, and performs transmission with the transmission
timing.
[0801] Since the timing of the SR response signal can be set to the
transmission timing of the uplink grant for the SR in the longer
duration even when the UE moves between the beams, the reception
timing of the SR response signal never ends before the UE moves
between the beams, and the UE can receive the SR response signal
via the target beam.
[0802] Another method will be disclosed.
[0803] Upon movement between beams or upon receipt of the
instruction for moving between beams from the cell, the UE resets
the timing of the SR response signal via the source beam.
[0804] The UE performs reception with the timing of the SR response
signal via the target beam, using, as a starting point (N), the
movement between beams or a subframe in which the instruction for
moving between beams has been received from the cell. The cell
performs transmission with the timing of the SR response signal via
the target beam, using, as a starting point (N), the movement of
the UE between beams or a subframe in which the instruction for
moving between beams has been transmitted.
[0805] Since the timing of the SR response signal can be set using,
as a starting point, the movement of the UE between beams, the
reception timing of the SR response signal via the target beam
never ends before the UE moves between the beams, and the UE can
receive the SR response signal via the target beam.
[0806] Another method to be applied when the transmission timing of
the uplink grant for the SR is set for each beam or for each UE and
each beam will be disclosed. The cell sets the timing of the SR
response signal via the target beam together with a moving
instruction to the UE. The cell sets the timing of the SR response
signal via the target beam, and notifies the UE of the timing of
the SR response signal as well as transmitting, to the UE, the
instruction for moving between the beams. When transmitting the
instruction for moving between beams to the UE, the cell resets the
timing of the SR response signal via the source beam, and performs
transmission with the timing of the SR response signal via the
target beam.
[0807] The UE receives the timing of the SR response signal via the
target beam as well as receiving the instruction for moving between
beams from the cell. When receiving the instruction for moving
between beams from the cell, the UE resets the timing of the SR
response signal via the source beam, and performs reception with
the timing of the SR response signal via the target beam.
[0808] The cell may newly set the timing of the SR response signal
after the UE moves to the target beam.
[0809] Consequently, the need for the SR transmission timing via
the source beam can be eliminated for the target beam. Thus, the
processes required between the beams can be facilitated.
[0810] Another method to be applied when the transmission timing of
the uplink grant for the SR is set for each beam or for each UE and
each beam will be disclosed. The transmission timing of the SR
response signal via the target beam is set dynamically since
transmission of the instruction for the UE to move between beams.
The cell dynamically sets the transmission timing of the SR
response signal via the target beam as well as transmitting, to the
UE, the instruction for the UE to move between beams.
[0811] Upon receipt of the instruction for moving between beams
from the cell, the UE resets the reception timing of the SR
response signal via the source beam. The UE consecutively receives
the SR response signals via the target beam after receiving the
instruction for moving between beams from the cell. For example,
when the transmission timing of the SR response signal is set per
subframe, the UE receives, in each subframe, the SR response signal
via the target beam. The cell may newly set, to the UE, the timing
of the SR response signal after the UE moves to the target
beam.
[0812] Consequently, when the cell notifies the UE of the
instruction for the UE to move between beams or before the UE moves
between beams, the cell does not have to notify, in advance, the UE
of the transmission timing of the SR response signal via the target
beam. This can reduce the amount of information necessary for
signaling.
[0813] Another method to be applied when the transmission timing of
the uplink grant for the SR is set for each beam or for each UE and
each beam will be disclosed. Even after the cell instructs the UE
to move, the timing of the SR response signal via the source beam
is maintained. Even after transmitting, to the UE, the instruction
for moving between beams, the cell performs transmission with the
transmission timing of the SR response signal via the source beam.
After transmitting, to the UE, the instruction for moving between
beams, the cell sets the transmission timing of the SR response
signal via the source beam to the transmission timing of the SR
response signal via the target beam.
[0814] Also after receiving the instruction for moving between
beams from the cell, the UE performs reception with the reception
timing of the SR response signal via the source beam. After
receiving the instruction for moving between beams from the cell,
the UE sets the transmission timing of the SR response signal via
the source beam to the transmission timing of the SR response
signal via the target beam.
[0815] The cell notifies the target beam of the timing setting for
the SR response signal via the source beam, after determining to
move the UE between beams and before the next transmission timing
of the SR response signal via the source beam. This is effective
when the source beam and the target beam are formed by different
nodes.
[0816] Alternatively, the node that forms the source beam notifies
the node that forms the target beam of the timing setting for the
SR response signal via the source beam, after the source beam
notifies the UE to move between beams and before the next
transmission timing of the SR response signal via the source beam.
This is effective when the source beam and the target beam are
formed by the different nodes and each of the nodes sets the timing
of the SR response signal.
[0817] Examples of the nodes include a TRP and a DU. The cell may
newly set, to the UE, the timing of the SR response signal after
the UE moves to the target beam.
[0818] A method to be applied when the transmission timing of the
uplink grant for the SR is set for each UE in the cell will be
disclosed. After the UE moves between beams, the cell and the UE
follow the timing setting for the SR response signal for each UE
that has been set before the move. The transmission timing of the
SR response signal may be determined using the transmission timing
of the SR as a starting point. The cell sets, to the UE, the
reception timing of the SR response signal for each UE.
[0819] After moving between beams or receiving the instruction for
moving between beams from the cell, the UE performs reception with
the set reception timing of the SR response signal for each UE. The
UE performs reception with the timing of the SR response signal for
each UE, using, as a starting point (N), the transmission timing of
the SR before moving between beams or before receiving the
instruction for moving between beams from the cell.
[0820] Consequently, a process of moving between beams can be
separated from a process of setting the transmission timing of the
SR response signal. Thus, malfunctions in a practical operation can
be reduced.
[0821] Even after the UE moves between beams or after the cell
transmits the instruction for moving between beams, the cell
performs transmission with the timing of the SR response signal set
for each UE. The cell performs transmission with the timing of the
SR response signal for each UE, using, as a starting point (N), the
reception timing of the SR before the UE moves between beams or
before the cell transmits the instruction for moving between
beams.
[0822] Consequently, the SR response signal timing set for each UE
need not be changed in moving between beams. Thus, the process of
moving between beams can be facilitated.
[0823] Although using the transmission timing of the SR as the
starting point is disclosed, the timing of the SR response signal
may be determined using, as a starting point, the timing of the UE
to move between beams or the timing for the cell to instruct the UE
to move between beams as an alternative method. The UE performs
reception with the timing of the SR response signal for each UE,
using, as a starting point (N), the movement between beams or the
reception timing of the instruction for moving between beams from
the cell. The cell performs transmission with the timing of the SR
response signal for each UE, using, as a starting point (N), the
movement of the UE between beams or the transmission timing of the
instruction for moving between beams.
[0824] Consequently, the need for the SR transmission timing via
the source beam can be eliminated for the target beam. Thus, the
processes required between the beams can be facilitated.
[0825] Another method to be applied when the transmission timing of
the uplink grant for the SR is set for each UE will be disclosed.
The method to be applied when the transmission timing of the uplink
grant for the SR is set for each beam or for each UE and each beam
may be applied. This is effective when the transmission timing of
the uplink grant for the SR for each UE is set in consideration of
the timing to be applied to the beam via which the UE
communicates.
[0826] FIGS. 25 and 26 illustrate one example sequence for setting
the transmission/reception timing of the uplink grant for the SR
upon movement between beams after transmission of the SR. FIGS. 25
and 26 are connected across a location of a border BL2. Since the
sequence illustrated in FIGS. 25 and 26 includes the same Steps as
those in the sequence illustrated in FIG. 24, the same step numbers
will be assigned to the same Steps and the common description
thereof will be omitted.
[0827] In Step ST2801, the cell sets, to the UE, a PUCCH resource
configuration for each UE.
[0828] In Step ST3201, the cell sets, to the UE, an SR response
timing for the UE.
[0829] In Step ST3202, the cell notifies the UE of the information
on the SR response together with the information on the PUCCH
resources. The cell may notify the information on the PUCCH
resources and the information on the SR response via a beam via
which the cell communicates with the UE. The cell notifies the
information on the PUCCH resources and the information on the SR
response via the RRC-dedicated signaling. Here, the beam via which
the cell communicates with the UE is the source beam.
[0830] After performing the process in Step ST3202, the cell
performs the processes in Steps ST2804, ST2805, and ST2806.
[0831] Upon receipt of the information on the PUCCH resources and
the information on the SR response in Step ST3202, the UE performs
the process in Step ST2803. Then, the UE performs the process in
Step ST2813.
[0832] In Step ST2811, the UE determines whether the uplink data
has been generated. When the uplink data has been generated, the UE
proceeds to Step ST2812A.
[0833] In Step ST2812A, the UE transmits the SR to the cell via the
serving beam with the set PUCCH resource configuration for the SR.
Here, the serving beam is the source beam.
[0834] Upon transmission of the SR in Step ST2812A, the UE starts
reception with the SR response timing derived from the information
on the SR response notified in Step ST3202.
[0835] In Step ST2812A, the cell receives the SR from the UE. Upon
receipt of the SR from the UE, the cell performs a process for the
uplink scheduling with the SR response timing set in Step
ST3201.
[0836] During this time, the cell transmits a downlink CSI-RS to
the UE via the source beam in Step ST3301.
[0837] Upon receipt of the downlink CSI-RS in Step ST3301, the UE
reports a measurement result of the CSI-RS to the cell via the
source beam in Step ST3302. Specifically, the UE reports the
measurement result of the CSI-RS to the cell as the CSI.
[0838] Here, the cell may transmit the CSI-RS via a plurality of
beams. The UE may notify the cell of a measurement result of the
CSI-RS transmitted via the plurality of beams. Alternatively, the
UE may derive a beam superior in the reception quality to the
serving beam from the measurement result of the CSI-RS, and notify
an identifier of the derived beam. Consequently, the amount of
information can be reduced.
[0839] Upon obtainment of the CSI report from the UE in Step
ST3302, the cell determines to move the UE to the target beam in
Step ST3303.
[0840] In Step ST3304, the cell determines whether the cell can
transmit, to the UE, an SR response with the SR response timing set
via the source beam.
[0841] When determining that the cell can transmit the SR response
with the SR response timing in Step ST3304, the cell proceeds to
Step ST3305.
[0842] In Step ST3305, the cell notifies the UE of an instruction
for moving to the target beam. The instruction for moving to the
target beam may include a beam identifier of the target beam. The
moving instruction may be notified via the L1/L2 control signaling.
Alternatively, the notification may be made via the MAC signaling.
The cell can notify the UE of the instruction for moving the beam
via the MAC signaling with lower latency than that via the RRC
signaling. The cell does not notify an instruction for changing to
the SR response timing, together with the moving instruction.
[0843] When determining that the cell cannot transmit the SR
response with the S R response timing in Step ST3304, the cell
proceeds to Step ST3306.
[0844] In Step ST3306, the cell changes the setting to the SR
response timing via the target beam for the UE.
[0845] In Step ST3307, the cell notifies the UE of the instruction
for moving to the target beam and an instruction for changing to
the SR response timing whose setting has been changed. The
instruction for changing the setting to the SR response timing may
include information on the SR response via the target beam.
[0846] In Step ST3308, the UE determines whether to have received
the instruction for changing the setting of the SR response timing,
together with the moving instruction received from the cell.
[0847] When determining that the UE does not receive the
instruction for changing the setting to the SR response timing in
Step ST3308, the UE proceeds to Step ST3309.
[0848] In Step ST3309, the UE continues to perform reception with
the SR response timing via the source beam.
[0849] Upon receipt of the instruction for changing the setting of
the SR response timing in Step ST3308, the UE proceeds to Step
ST3310.
[0850] In Step ST3310, the UE derives the SR response timing using
the received information on the SR response, and performs reception
with the setting changed to the derived SR response timing.
[0851] In Step ST3311, the cell performs the uplink scheduling via
the target beam with the SR response timing set to the UE.
[0852] In Step ST3312, the cell notifies the UE of the uplink grant
via the target beam with the SR response timing set to the UE.
[0853] In Step ST3312, the UE obtains the uplink grant from the
cell via the target beam with the set SR response timing.
[0854] In Step ST3313, the UE transmits a Buffer Status Report
(BSR) to the cell via the target beam using the obtained uplink
grant.
[0855] Upon receipt of the BSR in Step ST3313, the cell performs
the uplink scheduling for the UE according to the BSR.
[0856] In Step ST3314, the cell notifies the UE of the uplink grant
via the target beam.
[0857] Upon receipt of the uplink grant for the SR from the cell,
the UE transmits the uplink data to the cell in Step ST3315.
Consequently, the uplink communication is started between the UE
and the cell via the target beam.
[0858] In the case where the UE moves between beams after
transmitting the SR, even when the SR response timing is changed in
the target beam, the UE can receive the SR response signal via the
target beam.
[0859] FIGS. 27 and 28 illustrate another example sequence for
setting the transmission/reception timing of the uplink grant for
the SR upon movement between beams after transmission of the SR
FIGS. 27 and 28 are connected across a location of a border BL3.
Since the sequence illustrated in FIGS. 27 and 28 includes the same
Steps as those in the sequence illustrated in FIGS. 25 and 26, the
same step numbers will be assigned to the same Steps and the common
description thereof will be omitted.
[0860] In Step ST2801, the cell sets, to the UE, a PUCCH resource
configuration for each UE.
[0861] In Step ST3201, the cell sets, to the UE, an SR response
timing for the UE.
[0862] In Step ST3202, the cell notifies the UE of the information
on the SR response together with the information on the PUCCH
resources. The cell may notify the information on the PUCCH
resources and the information on the SR response via a beam via
which the cell communicates with the UE. The cell notifies the
information on the PUCCH resources and the information on the SR
response via the RRC-dedicated signaling. Here, the beam via which
the cell communicates with the UE is the source beam.
[0863] After performing the process in Step ST3202, the cell
performs the processes in Steps ST2804, ST2805, and ST2806.
[0864] Upon receipt of the information on the PUCCH resources and
the information on the SR response in Step ST3202, the UE performs
the process in Step ST2803. Then, the UE performs the process in
Step ST2813.
[0865] In Step ST2811, the UE determines whether the uplink data
has been generated. When the uplink data has been generated, the UE
proceeds to Step ST2812A.
[0866] In Step ST2812A, the UE transmits the SR to the cell via the
serving beam with the set PUCCH resource configuration for the SR.
Here, the serving beam is the source beam.
[0867] Upon transmission of the SR in Step ST2812A, the UE starts
reception with the SR response timing derived from the information
on the SR response notified in Step ST3202.
[0868] In Step ST2812A, the cell receives the SR from the UE. Upon
receipt of the SR from the UE, the cell performs a process for the
uplink scheduling with the SR response timing set in Step
ST3201.
[0869] During this time, the cell transmits the downlink CSI-RS to
the UE via the source beam in Step ST3301.
[0870] Upon receipt of the downlink CSI-RS in Step ST3301, the UE
reports a measurement result of the CSI-RS to the cell via the
source beam in Step ST3302. Specifically, the UE reports the
measurement result of the CSI-RS to the cell as the CSI.
[0871] Here, the cell may transmit the CSI-RS via a plurality of
beams. The UE may notify the cell of a measurement result of the
CSI-RS transmitted via the plurality of beams. Alternatively, the
UE may derive a beam superior in the reception quality to the
serving beam from the measurement result of the CSI-RS, and notify
an identifier of the derived beam. Consequently, the amount of
information can be reduced.
[0872] Upon obtainment of the CSI report from the UE in Step
ST3302, the cell determines to move the UE to the target beam in
Step ST3303.
[0873] In Step ST3305, the cell notifies the UE of an instruction
for moving to the target beam.
[0874] Upon receipt of the moving instruction in Step ST3305, the
UE resets the SR response timing via the source beam, and sets
reception in each subframe in Step ST3403.
[0875] Upon transmission of the moving instruction to the UE in
Step ST3305, the cell resets the SR response timing via the source
beam that has been set to the UE, and dynamically sets the SR
response timing in Step ST3401.
[0876] In Step ST3402, the cell performs the uplink scheduling for
the UE with an arbitrary timing.
[0877] In Step ST3312, the cell transmits the uplink grant to the
UE. The cell transmits the uplink grant via the target beam.
[0878] The UE, which has been set to perform reception in each
subframe upon receipt of the moving instruction in Step ST3403,
performs reception in each subframe via the target beam from then
onward.
[0879] Consequently, the UE can receive the uplink grant
transmitted from the cell in Step ST3312.
[0880] Upon receipt of the uplink grant for the SR from the cell,
the UE performs processes for starting the uplink communication
with the cell via the target beam from Steps ST3313 to ST3315.
Consequently, the uplink communication is started between the UE
and the cell.
[0881] In the case where the UE moves between beams after
transmitting the SR, even when the SR response timing is changed in
the target beam, the UE can receive the SR response signal via the
target beam.
[0882] The cell can perform the uplink scheduling for the SR from
the UE and transmit the uplink grant, with an arbitrary timing via
the target beam. The UE can receive the uplink grant even when the
uplink grant is transmitted with the arbitrary timing. The cell can
perform the uplink scheduling for the SR with appropriate timing
where appropriate, according to, for example, a load state of each
beam and a radio propagation environment.
[0883] A problem occurs when the transmission of the SR is
undelivered via the target beam. Examples of the problem include
whether the setting of the source beam is used as it is, whether
the new setting is made via the target beam, and how to make the
new setting if the new setting is made.
[0884] The setting of the transmission timing of the uplink grant
for the SR via the target beam and its setting method that are
previously disclosed may be applied to the case where the
transmission of the SR is undelivered. The cell and the UE can
perform coordinated operations via the target beam even when the
transmission of the SR is undelivered.
[0885] The retransmission of the SR from the UE via the target beam
will cause another problem. For example, when the UE performs
uplink transmission via the target beam and a
transmission/reception point for the source beam (hereinafter may
be referred to as an "S-TRP") is different from a
transmission/reception point for the target beam (hereinafter may
be referred to as a "T-TRP"), a radio propagation time from the UE
to the S-TRP is different from a radio propagation time from the UE
to the T-TRP.
[0886] Even when the UE performs the uplink transmission via the
target beam, using the timing advance (TA) in the source beam, the
cell has a problem of failing to receive the uplink transmission in
the T-TRP.
[0887] The retransmission of the SR from the UE via the target beam
causes the similar problem. No matter how many times the UE
repeatedly retransmits the SR via the target beam, the cell can
neither receive the retransmitted SR nor transmit the uplink grant
to the UE. Consequently, the UE has a problem of failing to start
the uplink transmission.
[0888] A method for solving such a problem will be disclosed.
[0889] The cell instructs the UE to start the RA procedure
dedicated to the UE via the target beam, together with the moving
instruction. In the RA procedure dedicated to the UE, a
configuration dedicated to the UE is used as an RA preamble. Thus,
the RA procedure can be reliably performed without any
conflict.
[0890] The RA preamble configuration dedicated to the UE includes a
sequence of signals to be used for radio resources and the
preamble. The cell notifies the UE of information on the RA
preamble via the target beam. The cell may include the information
in signaling for the moving instruction via the source beam to
notify the UE of the information. The notification of the
information may initiate the RA procedure dedicated to the UE.
[0891] Upon receipt of the information on the RA preamble via the
target beam together with the moving instruction, the UE performs
the RA procedure dedicated to the UE via the target beam. This RA
procedure enables the UE to obtain the timing advance from the cell
via the target beam. Upon obtainment of the timing advance via the
target beam, the UE performs uplink transmission using the timing
advance.
[0892] Consequently, the cell can receive the uplink transmission
from the UE via the target beam. Similarly, the UE retransmits the
SR using the timing advance. Consequently, the cell can receive the
SR retransmitted from the UE via the target beam.
[0893] When the cell determines that the timing advance for the UE
via the source beam is different from that via the target beam, the
cell may start the RA procedure dedicated to the UE for the UE. The
cell starts the RA procedure dedicated to the UE for the UE when,
for example, positions of the S-TRP and the T-TRP are different.
When the positions of the S-TRP and the T-TRP are the same or when
the same TRP configures the source beam and the target beam, the
cell does not start the RA procedure dedicated to the UE for the
UE.
[0894] When the positions of the S-TRP and the T-TRP are the same
or when the same TRP configures the source beam and the target
beam, the radio propagation times from the UE are almost equal to
each other. Thus, there is no need to reset the timing advance via
the target beam, and the timing advance via the source beam may be
continuously used.
[0895] This eliminates the need for always initiating the RA
procedure when the UE moves between beams. Thus, the processes in
the UE and the cell can be facilitated, and the power consumption
can be reduced.
[0896] Another method will be disclosed. A Timing Advance Group
(TAG) for each beam or for each TRP is set. Conventionally, the TAG
is set for each cell. What is being studied in the NR is that one
or more TRPs are configured in a cell and each of the TRPs forms
one or more beams. When positions of the TRPs that form beams are
different, the timing advances are different as described above.
Setting the TAG for each beam or for each TRP enables the TAG to be
set according to a difference in position between the TRPs each of
which forms beams.
[0897] The cell may determine whether the target beam is within the
same TAG as that of the source beam to start the RA procedure
dedicated to the UE for the UE. When the target beam is within the
same TAG as that of the source beam, the cell does not start the RA
procedure dedicated to the UE for the UE. When the target beam is
within a TAG different from that of the source beam, the cell
starts the RA procedure dedicated to the UE for the UE.
Consequently, the same advantages as those in the seventh
embodiment can be produced.
[0898] Although the cell determines to start the RA procedure for
the UE, the UE may determine to start the RA procedure. The cell
notifies, in advance, the UE of the TAG setting information for
each beam or for each TRP. The method for notifying the TAG setting
information may be the RRC signaling. Alternatively, the
notification may be made via the MAC signaling.
[0899] Upon receipt of the instruction for moving between beams
from the cell, the UE determines whether the target beam is within
the same TAG as that of the source beam, from the identifier of the
target beam included in the moving instruction with reference to
the TAG setting information. When the target beam is within the
same TAG as that of the source beam, the UE does not start the RA
procedure dedicated to the UE. When the target beam is within a TAG
different from that of the source beam, the UE starts the RA
procedure. The cell may notify the UE of the information on the RA
preamble via the target beam, together with the moving
instruction.
[0900] The UE may perform an RA procedure that is not dedicated to
the UE. The cell need not notify the UE of the information on the
RA preamble via the target beam, together with the moving
instruction. The UE may apply information on the RA preamble that
is set for each cell or for each beam to the RA procedure. The
information may be predetermined in, for example, a standard, or
notified in advance from the cell to the UE. The method for
notifying the information on the RA preamble may be the RRC
signaling. Consequently, the UE can start the RA procedure.
[0901] Upon start of the RA procedure via the target beam in such a
manner, the UE retransmits the SR via the target beam using the
timing advance obtained in the RA procedure. The UE that does not
start the RA procedure via the target beam retransmits the SR via
the target beam, continuously using the timing advance via the
source beam.
[0902] Consequently, the UE can retransmit the SR via the target
beam, even when the transmission of the SR via the source beam is
undelivered. Moreover, starting from the RA procedure in the
retransmission of the SR via the target beam enables the UE to
avoid earlier a situation where the transmission of the SR
continues to be undelivered due to different TAs. Thus, the UE can
start the uplink transmission earlier.
[0903] Such a method further enables the UE to retransmit the SR
via the target beam, even when the transmission of the SR via the
source beam and retransmission of the SR at least once are
undelivered.
[0904] The maximum number of times the SR is retransmitted may be
reset upon issuance of the instruction for moving between beams.
Assuming the first retransmission of the SR via the target beam as
the initial retransmission of the SR or the initial transmission of
the SR, the UE may retransmit the SR again until the maximum number
of times the SR is retransmitted. This can provide sufficient
opportunities for retransmitting the SR via the target beam. Thus,
the undelivered transmission of the SR can be reduced.
[0905] The maximum number of times the SR is retransmitted may be
reset only for the UE that has started the RA procedure via the
target beam. Assuming the first retransmission of the SR via the
target beam as the initial retransmission of the SR or the initial
transmission of the SR, the UE may retransmit the SR again until
the maximum number of times the SR is retransmitted. This can
provide only the UE whose TA has been changed with sufficient
opportunities for retransmitting the SR. Thus, the undelivered
transmission of the SR can be reduced. The RA procedure can be
performed again earlier without unnecessarily increasing a duration
until reaching the maximum number of times for the UE whose TA has
not been changed yet.
[0906] When starting the RA procedure, the UE may reset the SR
procedure. After starting the RA procedure, the UE may start the SR
procedure. The UE may start from the setting of the PUCCH resources
in the target beam. Here, the information on the PUCCH resources
identical to that in the source beam may be omitted. Consequently,
the UE can start the SR procedure via a target beam with the
different TA.
Eighth Embodiment
[0907] In the NR, the analog beamforming and the hybrid beamforming
are being studied. One cell forms a plurality of beams, and forms a
coverage for each of the beams. Thus, the coverage of the beam is
narrower than the coverage of the cell.
[0908] Unless the coverage of the beam is appropriately formed, a
problem of a high probability of disconnection in communication
during the movement of the UE between beams occurs. When a new
obstacle is formed, problems such as a coverage hole and decrease
in the received power depending on a location occur.
[0909] In the LTE, minimization of drive tests (MDT) is supported
as an evaluation function of the coverage by the UE (see 3GPP TS
37.320 V13.1.0 (hereinafter referred to as "Reference 8"), 3GPP TS
36.331 V14.0.0 (hereinafter referred to as "Reference 5"), and
Non-Patent Document 1).
[0910] The conventional MDT is a function causing the UE to
measure, record, and report how much received power can be obtained
from the cell in a geographical point in order to evaluate how the
cell forms the coverage. The cell obtains, from the UE, the report
of the received power from one or more cells in a measurement point
to use the report for forming the coverage of the cell. This can
form, for example, a coverage that reduces a zone where
communication is disconnected due to a handover failure, etc.
[0911] Since the conventional MDT aims at forming a coverage of a
cell, it has a problem of being inapplicable to appropriate
formation of a coverage for each beam which is being studied in the
NR.
[0912] The eighth embodiment will disclose a method for solving
such a problem.
[0913] An identifier of a beam is introduced into the MDT. In the
presence of an identifier of a TRP, the identifier of the TRP may
be introduced into the MDT. The identifier of the TRP and the
identifier of the beam may be introduced into the MDT in
combination. Such a method may be referred to as MDT for each beam
in the following description.
[0914] A specific example of introducing a beam identifier into the
MDT will be disclosed.
[0915] An identifier of a beam at the time of measurement is logged
into a log in which the UE records a measurement result. The
identifier of the beam at the time of measurement may be logged in
a measurement result for each cell according to the conventional
MDT. The identifier of the beam is associated with a reference
signal (RS) to be transmitted for each beam (may be hereinafter
referred to as a "BRS"). Examples of the identifier of the beam may
include a beam number.
[0916] Upon receipt of the BRS transmitted for each beam, the UE
obtains the identifier of the beam. The UE records, in the log, an
identifier of the cell, information on a measurement point, and a
measurement result of the received power at the measurement point.
The identifier of the beam via which reception is being performed
at the measurement point is added to this log.
[0917] The received power of the BRS may be measured as the
received power at the measurement point.
[0918] The UE records, in the log, the identifier of the cell,
information on the measurement point, and a measurement result of
the received power or the reception quality at the measurement
point based on the conventional MDT. Further adding, to this, the
identifier of the beam via which reception is being performed at
the measurement point shows from which beam the reception is being
performed at the measurement point. The UE adds the identifier of
the beam via which reception is being performed at the measurement
point to the log for recording to report the identifier of the beam
to the cell. Consequently, the cell can recognize from which beam
the UE can perform reception at the measurement point, and
determine how the coverage of the beam is formed.
[0919] Since mere addition of the identifier of the beam to the
conventional MDT is necessary, a change can be easily made.
[0920] Another method will be disclosed.
[0921] The UE measures the received power for each beam, and
records the measurement result in a log. The UE notifies the cell
of the log. The UE records the measurement result in the log in
association with an identifier of a measured beam. The identifier
of the beam may be derived by receiving the BRS for each beam as
previously described. The UE records, in the log, an identifier for
each beam, information on a measurement point, and a measurement
result of the received power (or may be the reception quality) for
each beam at the measurement point.
[0922] The number of beams to be measured may be one or more. A
beam to be measured may be not limited to a serving beam. The beams
to be measured may include another beam in the same TRP, another
beam in the same cell, a beam in another TRP, and a beam in another
cell. The cell may determine a beam to be measured by the UE, and
notify the UE of the beam. Alternatively, the beam to be measured
by the UE may be a beam that can be measured by the UE.
[0923] The maximum value may be set to the number of beams that the
UE records in the log. The maximum value of the number of beams
that the UE records in the log may be provided for each cell.
Alternatively, the maximum value of the number of beams that the UE
records in the log may be provided for each TRP. Alternatively, the
maximum value of the number of beams that the UE records in the log
may be provided for each frequency. When the number of measurable
beams is excessive, the beams to be recorded in the log can be
restricted. Thus, increase in the recording capacity of the UE can
be suppressed. These maximum numbers may be predetermined in a
standard, or notified from the cell to the UE. The maximum numbers
may be notified via the RRC-dedicated signaling.
[0924] The following (1) to (5) will be disclosed as specific
examples of a signal for measuring the received power for each
beam:
[0925] (1) a synchronization signal (SS);
[0926] (2) a BRS;
[0927] (3) a Demodulation RS (DMRS);
[0928] (4) channel status information-RS (CSI-RS); and
[0929] (5) combinations of (1) to (4) above.
[0930] The SS in (1) can be used irrespective of an RRC connected
state of the UE. The UE can measure the SS both in an RRC_Idle
state and in an RRC_Connected state. The UE may measure the SS as
Radio Resource Management (RRM) measurement. In the NR,
transmitting, as the SS, a signal common to all beams in a cell via
each of the beams is being studied. The UE may store, in a log, a
measurement result of the SS for each beam and an identifier of the
beam via which the SS has been measured in association with each
other.
[0931] The BRS in (2) can be used irrespective of an RRC connected
state of the UE. The UE can measure the BRS both in an RRC_Idle
state and in an RRC_Connected state. The UE may measure the BRS as
the RRM measurement. Alternatively, the UE may measure the BRS as
the RLC measurement or the PHY measurement. In the NR, transmitting
the BRS for each beam is being studied. The UE may store, in a log,
a measurement result of the BRS for each beam and an identifier of
the beam via which the BRS has been measured in association with
each other.
[0932] The DMRS in (3) can be used when the UE is in an RRC
connected state. The UE can measure the DMRS in an RRC connected
state. The UE may measure the DMRS as the RLC measurement.
Alternatively, the UE may measure the DMRS as the PHY measurement.
In the NR, transmitting the DMRS for demodulation together with the
downlink data or a downlink control signal of the UE is being
studied. The UE may store, in a log, a measurement result of the
DMRS and an identifier of the beam via which the DMRS has been
measured in association with each other.
[0933] The CSI-RS in (4) can be used when the UE is in an RRC
connected state. The UE can measure the CSI-RS in an RRC connected
state. The UE may measure the CSI-RS as the RLC measurement.
Alternatively, the UE may measure the CSI-RS as the PHY
measurement. In the NR, transmitting the CSI-RS for each beam or
each antenna to evaluate a channel state of the beam is being
studied. The UE may store, in a log, a measurement result of the
CSI-RS and an identifier of the beam via which the CSI-RS has been
measured in association with each other.
[0934] The cell or the TRP may form, using a single beam, a
coverage almost equivalent to all the coverages formed by a
plurality of beams. The UE may measure, also for the single beam,
the received power via the single beam, and record the measurement
result in a log. The aforementioned method is appropriately
applicable to this case. Besides (1) to (4) above, the received
power of an RS to be transmitted as a single beam may be measured
as a signal for measuring the received power for each beam. (1) to
(4) above may be combined.
[0935] Although forming multi-beams in the UE is being studied in
the NR, a single beam may be formed in measurement by the UE. The
UE measures the received power for each beam formed by the cell via
a single beam, and records the result in a log. The influence of
the beam formed by the UE can be eliminated from the measurement
result of the received power for each beam formed by the cell.
[0936] When the UE cannot form a single beam, a measurement result
via the multi-beams may be converted into a measurement result via
the single beam according to a predefined conversion method. The UE
may perform measurement by the multi-beams using beam sweeping. The
predefined conversion method may be statically determined in, for
example, a standard. This can avoid increase in the signaling
required for notifying the conversion method, and facilitates the
conversion. Alternatively, the predefined conversion method may be
semi-statically or dynamically notified to the UE. This is
effective when, for example, the number of beams in the multi-beams
and an association with a single beam are changed semi-statically
or dynamically.
[0937] When the notification is made to the UE semi-statically or
dynamically, it is possible to predetermine a plurality of
conversion methods and give an indication indicting each of the
methods, so that the cell may notify the UE of the indication. This
can reduce the amount of information to be signaled.
[0938] The conventional MDT has been performed using the RRM
measurement. In the NR, however, measuring beams using not the RRM
measurement but the RLC measurement or the PHY measurement is being
studied. When beams are measured using the RLC measurement or the
PHY measurement, the received power for each beam may be measured
using the RLC measurement or the PHY measurement. This can
eliminate the need for the RRM measurement in measuring beams.
[0939] Methods for measuring the received power for each beam and
recording the received power in a log will be disclosed.
[0940] A predefined condition may be set to the measurement result
of the received power. If the predefined condition is met, the
measurement result is recorded in a log. If the predefined
condition is not met, the measurement result is not recorded in a
log.
[0941] For example, a threshold is set to the measurement result of
the received power. For example, the measurement result may be
recorded in a log when the measurement result is larger than the
threshold. The measurement result may not be recorded in a log when
the measurement result is smaller than or equal to the
threshold.
[0942] The cell may notify the UE of the predefined condition. For
example, the cell may include the predefined condition in a message
for notifying the MDT setting to notify the predefined
condition.
[0943] As an alternative method, the received power may be
periodically measured, and the measurement result may be recorded
in a log. The cell may notify the UE of a preset period. For
example, the cell may include the preset period in a message for
notifying the MDT setting to notify the preset period. The period
may be a measurement period for the MDT.
[0944] The period may be set in synchronization with an operation
duration (an active duration) of the DRX. The synchronization with
the active duration saves the reception operation for measuring the
received power during an inactive duration in the DRX. Thus, the
power consumption of the UE can be reduced.
[0945] A method for notifying a log from the UE to the cell will be
disclosed.
[0946] In an RRC_Idle state, the cell may notify the UE of a
request for reporting the MDT result. Upon receipt of the request,
the UE notifies the cell of the log. These notifications may be
made via the RRC signaling.
[0947] The UE information procedure existing in the LTE may be used
for requesting a report of the MDT result and for reporting the MDT
result. A UE Information Request is used for requesting the report
of the MDT result, and a UE Information Response is used for
reporting the MDT result. This is effective because no additional
signaling is necessary when the methods disclosed in the eighth
embodiment are applied to the LTE.
[0948] In an RRC connected state, a log may be included in a
measurement report to be notified. The cell makes the setting for
the UE to cause the UE to perform a measurement report. The cell
may set a measurement report of the MDT result. Upon receipt of the
setting for the measurement report, the UE includes the log in the
measurement report to notify the cell of the log, according to the
setting.
[0949] Alternatively, the log may be notified as a CSI report. The
cell makes the setting for the UE to cause the UE to perform the
CSI report. The cell may set the CSI report of the MDT result. Upon
receipt of the setting for the CSI report, the UE includes the log
in the CSI report to notify the cell of the log, according to the
setting. This is effective when the measurement result of the
CSI-RS is logged.
[0950] Alternatively, a new message may be provided for notifying
the log. The cell makes the setting of a report of the log for the
UE, in a message requesting the report of the log. Upon receipt of
the setting for requesting the report of the log, the UE includes
the log in a message reporting the log to notify the cell of the
log, according to the setting. These new messages may be notified
via the RRC signaling.
[0951] Consequently, the cell can recognize from which beam and to
what extent the UE can perform reception at a measurement point of
the UE. Consequently, how the coverage of the beam is formed can be
more precisely determined. This can form, for example, a coverage
that reduces a zone where communication is disconnected due to a
handover failure, etc.
[0952] Conventionally, a CN can request the MDT from an eNB in the
LTE. The CN may request the MDT for each beam or the MDT for each
TRP from a gNB so that the MDT is compatible with a coverage for
each beam that is being studied in the NR. The CN notifies the gNB
of a message requesting the MDT for each beam or for each TRP. The
CN may make the notification using an interface to be set between
the CN and the gNB in the 5G.
[0953] A conventional MDT request message may be used. Since the
conventional MDT request message is "Trace Start" and the S1
signaling is used, the CN may make the notification using the
interface to be set between the CN and the gNB in the 5G to enable
the gNB to be notified.
[0954] The CN includes the MDT configuration in the "Trace Start"
message to notify the eNB of the MDT configuration. Upon receipt of
the MDT configuration in the "Trace Start" message, the eNB
instructs the cell to cause the UE to execute the MDT.
[0955] Information in the MDT configuration in the "Trace Start"
message includes setting information on a MDT area. The setting
information on the MDT area is "CHOICE Area Scope of MDT".
Conventionally, "CHOICE Area Scope of MDT" enables only the setting
in the cell or in a tracking area.
[0956] A new beam setting may be added to "CHOICE Area Scope of
MDT". The TRP setting may be added thereto. For example,
information indicating whether the MDT for each beam is performed
or information indicating whether the MDT for each TRP is performed
can be set. Moreover, an identifier of a beam to be set in the MDT
or an identifier of a TRP to be set in the MDT may be set.
[0957] Consequently, the CN can cause the gNB to execute the MDT
for each beam or for each TRP.
[0958] The CN may set, for example, a signal for measuring the
received power for each beam, a predefined condition, and a
threshold. The information in the MDT configuration in the "Trace
Start" message includes setting information on, for example, a
measurement signal. The setting information on, for example, the
measurement signal is "CHOICE MDT Mode". The settings of the signal
for measuring the received power for each beam, the predefined
condition, and the threshold may be newly added. For example,
information indicating which signal is measured, information
indicating a predefined condition for recording a measurement
result of the received power in a log, or information indicating a
threshold can be set as a signal for measuring the received power
for each beam.
[0959] Consequently, the CN can set, to the gNB, which signal is
measured and based on which condition the log is obtained in the
MDT for each beam or for each TRP.
Ninth Embodiment
[0960] In the LTE channel coding, a data block to be channel coded,
that is, a transport block is divided into code blocks of a certain
size or less that is predefined in a standard. Then, the coding is
performed for each of the code blocks. It is expected in the NR
that the broadening of use frequency band increases the size of the
transport block and as a result, increases the number of code
blocks.
[0961] In the LTE channel coding, a CRC bit is provided for each of
the code blocks and for the whole transport block. In the Ack/Nack
feedback of the LTE, a receiver transmits Nack to a transmitter
when even one of the code blocks in the received transport block
has a CRC error. The transmitter retransmits the whole transport
block to the receiver. Thus, simultaneous retransmission of the
code blocks received with CRC=OK wastes communication.
[0962] In the NR, 3GPP R1-1609744 (hereinafter referred to as
"Reference 9") proposes that the receiver should feed back the
number of the code block that cannot be accurately decoded and the
transmitter should perform HARQ retransmission of only the code
block that has been fed back to perform efficient HARQ
retransmission. Reference 9 also proposes that the gNB should set,
to each UE, the number of bits in the feedback semi-statically via
a control signaling, or dynamically according to the transport
block size via a control signaling.
[0963] Further in the NR, 3GPP R1-1612072 (hereinafter referred to
as "Reference 10") proposes bundling or grouping code blocks by a
predefined number to save the number of bits in the feedback from
the receiver to the transmitter, and proposes that the receiver
should feed back the bundling number of the code blocks including
the code block that cannot be accurately decoded. Reference 10 also
proposes that the gNB should determine the predefined number.
[0964] However, Reference 10 fails to disclose details on
determining the number of code blocks per bundling in feeding back
the bundling number of the code blocks.
[0965] When a specific symbol has a reception error, the number of
code blocks to be fed back is two or more, or the number of bundles
of the code blocks is two or more. Thus, a problem of increase in
the number of feedbacks occurs. Examples of the reception error in
the specific symbol include a URLLC interrupt.
[0966] FIG. 29 illustrates reception errors in code blocks due to
the URLLC interrupt. In FIG. 29, one transport block is transmitted
in one subframe. The transport block is divided into code blocks
(hereinafter may be referred to as "CBs") #1 to #19. The code
blocks are mapped from the first symbol in the one subframe in
order.
[0967] As illustrated in FIG. 29, the CBs to be mapped to each
symbol vary among the symbols. For example, if a URLLC interrupt
occurs in the fourth symbol, the original CBs #9 and #10 cannot be
transmitted at all, and the CB #11 can be transmitted only
partially as illustrated in FIG. 29. Here, the total three CBs of
the CB #9 to the CB #11 have reception errors. On the other hand,
since the total four CBs of the CB #11 to the CB #14 are mapped to
the fifth symbol, the four CBs will have reception errors if a
URLLC interrupt occurs in the fifth symbol. The number of CBs per
bundling is constant according to the conventional method. Thus, it
is necessary to feed back a plurality of bundling numbers to the
feedback of the reception errors in the CBs caused by the URLLC
interrupt. This creates a problem of increase in the number of bits
required for the feedback.
[0968] The ninth embodiment will disclose a method for solving such
a problem.
[0969] The maximum number of code blocks per code block group (may
be hereinafter referred to as "CBG") may be determined when code
blocks in a transport block are grouped. The number of CBGs may be
determined using the maximum number of code blocks per CBG. For
example, dividing the number of code blocks by the maximum number
of code blocks per CBG and rounding up decimal places may give a
value indicating the number of CBGs.
[0970] Thus, in the feedback on the CBGs from the receiver to the
transmitter, the number of times code blocks that have been
accurately received (the reception result shows OK) are wastefully
retransmitted can be reduced to lower than or equal to a certain
value.
[0971] The HARQ feedback according to the ninth embodiment differs
from the ARQ in the RLC in grouping the code blocks with the
reception errors and feeding back the result to the
transmitter.
[0972] How to allocate the number of code blocks to each CBG may
be, for example, to group the code blocks into a CBG with the
maximum number of code blocks and a CBG with the remaining number
of code blocks. The CBG with the remaining number of code blocks
may include the first code block or the last code block. Including
the first code block in the CBG with the remaining number of code
blocks enables reduction in the number of code blocks to be
allocated to a CBG including the MAC header placed in the beginning
of a transport block, and reception of such a CBG with a fewer
number of retransmissions. Consequently, the receiver can obtain
the MAC header earlier.
[0973] As a specific example, assuming that the number of code
blocks is 50 and the maximum number of code blocks per CBG is 8,
the number of CBGs is 7. How to allocate the number of code blocks
to each CBG is to allocate 8 code blocks to 6 CBGs and allocate 2
code blocks to the remaining one CBG.
[0974] For another example of the allocation, the number of code
blocks may be evenly allocated to each CBG. The CBG with the
maximum number of code blocks may be placed in the beginning or at
the end. When the number of code blocks are evenly allocated in the
aforementioned specific example, 1 CBG consists of 8 code blocks
and the remaining 6 CBGs each consist of 7 code blocks. This can
prevent a bias between the CBGs in the number of times code blocks
are wastefully retransmitted.
[0975] Another method for grouping the code blocks may include
determining the number of CBGs. The maximum number of code blocks
per CBG may be determined using the number of CBGs. For example,
dividing the number of code blocks by the number of CBGs and
rounding up decimal places may give a value indicating the maximum
number of code blocks per CBG. Consequently, the number of bits
required for the feedback per CBG can be constant.
[0976] The code blocks may be allocated similarly as the grouping
of the code blocks for which the maximum number of code blocks per
CBG has been determined, in grouping the code blocks for which the
number of CBGs has been determined. For example, the code blocks
may be grouped into a CBG with the maximum number of code blocks
and a CBG with the remaining number of code blocks. The CBG with
the remaining number of code blocks may include the first code
block or the last code block. When the CBG with the remaining
number of code blocks includes the first code block, the receiver
can obtain the MAC header earlier.
[0977] As a specific example, assuming that the number of code
blocks is 50 and the number of CBGs is 8, the maximum number of
code blocks per CBG is 7. How to allocate the number of code blocks
to each CBG is to allocate 7 code blocks to 7 CBGs and allocate 1
code block to the remaining one CBG.
[0978] For another example of the allocation, the number of code
blocks may be evenly allocated to each CBG. When the number of code
blocks are evenly allocated in the aforementioned specific example,
2 CBGs each consist of 7 code blocks and the remaining 6 CBGs each
consist of 6 code blocks. This can prevent a bias between the CBGs
in the number of times code blocks are wastefully
retransmitted.
[0979] In grouping of code blocks, the number of CBGs or the
maximum number of code blocks per CBG may have a default value. The
positioning of the CBGs may have a default setting. For example,
the default value of the number of CBGs may be 1. As an alternative
example, the maximum number of code blocks per CBG may be identical
to the number of code blocks in a transport block. Alternatively,
the CBG with the maximum number of code blocks or with the minimum
number of code blocks may be placed in the beginning as an example
default setting for positioning the CBGs.
[0980] A method for grouping the CBGs may be determined in a
standard. For example, a fixed value may be used. As an example of
the fixed value, the number of CBGs may be fixed to, for example,
16. As an alternative example of determining the method in a
standard, the method may be determined using the maximum number of
code blocks that the UE can transmit or receive. The maximum
transport block size that the UE can transmit or receive, or the UE
category may be used.
[0981] A propagation environment may be used as an alternative
example of determining the method in a standard. The propagation
environment may be indicated by the CQI/CSI. For example, when the
CQI/CSI is superior, the maximum number of code blocks per CBG may
be reduced. This can reduce the overhead incurred by retransmission
of code blocks that have accurately been received among the CBGs
having reception errors when the CBGs are fed back.
[0982] A reception error rate may be used as an alternative example
of determining the method in a standard. For example, when the
reception error rate is high, the CBGs having reception errors can
be fed back to the transmitter with less number of bits by
increasing the maximum number of code blocks per CBG.
[0983] The gNB may determine the method for grouping the CBGs.
Information necessary for the gNB to group the CBGs may be the same
as that when the method is determined in a standard.
[0984] Alternatively, the gNB may determine the method using the
number of bits that the gNB can use to perform the HARQ feedback
for the UE.
[0985] As an example of using the number of bits in the HARQ
feedback, the number of bits may be identical to the number of
CBGs, and the gNB may feed back information on Ack/Nack for each
CBG. Assume a case where, for example, the number of bits is 4, 1
is associated with a CBG having a reception error, and 0 is
associated with a CBG without a reception error. In the case where
a code block belonging to a CBG #3 has a reception error, the bit
string that the gNB feeds back to the UE may be "0010". For another
example, combinations of the CBGs having reception errors may be
associated with values indicated by the bit string. For example, a
value 0 may be associated with the absence of a reception error.
Values 1, 2, 3, and 4 may be associated with cases where only a CBG
#1, only a CBG #2, only the CBG #3, and only a CBG #4 have
reception errors, respectively. A value 5 may be associated with a
case where the CBGs #1 and #2 have reception errors. A value 6 may
be associated with a case where the CBGs #1 and #3 have reception
errors. A value 11 may be associated with a case where the CBGs #1,
#2, and #3 have reception errors. A value 12 may be associated with
a case where the CBGs #1, #2, and #4 have reception errors. A value
15 may be associated with a case where all the four CBGs have
reception errors.
[0986] The UE may find a code block belonging to a CBG that cannot
be received, using the number of bits in the HARQ feedback and the
values of the bit string. Since the gNB need not notify the UE of
the information necessary for grouping the CBGs in the uplink
communication, the amount of signaling can be reduced. Even when
the number of CBGs including the code blocks having reception
errors increases, the number of bits to be fed back to the UE can
be constant without any increase.
[0987] The method for grouping the CBGs may be determined using the
number of bits that the UE can use to perform the HARQ feedback for
the gNB. For example, the method may be determined using the number
of bits that the UE can use to perform the HARQ feedback as
previously described. Consequently, the same advantages can be
produced in the downlink communication.
[0988] The following (1) to (5) will be disclosed as specific
examples of a means for the gNB to notify the UE of the method for
grouping the CBGs:
[0989] (1) broadcasting to the UEs being served thereby;
[0990] (2) the control signaling for each UE, for example, the
RRC-dedicated signaling;
[0991] (3) the MAC control information;
[0992] (4) the L1/L2 signaling; and
[0993] (5) combinations of (1) to (4) above.
[0994] Since application of (1) enables simultaneous notification
of the method for grouping the CBGs to a plurality of UEs, the
amount of signaling can be reduced.
[0995] Since application of (2) allows the semi-static notification
to each UE, the setting appropriate for a UE-dedicated state can be
made with less signaling.
[0996] With application of (3), for example, the HARQ
retransmission control enables the notification to the UE with high
reliability, according to short-term variations in the propagation
environment.
[0997] Application of (4) enables the dynamic notification even in
the absence of user data to be transmitted from the gNB to the
UE.
[0998] The maximum number of code blocks per CBG may be used as a
detail to be notified from the gNB to the UE in the method for
grouping the CBGs. Alternatively, the number of CBGs may be used.
An identifier indicating a method for allocating code blocks to the
CBGs may be notified together with the maximum number of code
blocks per CBG or the number of CBGs. The identifier may indicate,
for example, whether the CBGs are grouped into the CBG with the
maximum number of code blocks and the CBG with the remaining number
of code blocks, whether the number of code blocks is evenly
allocated to each CBG, and whether the CBG with the maximum number
of code blocks is placed in the beginning or at the end in each of
the previous two cases.
[0999] With regard to the number of bits to be used in the HARQ
feedback, Ack may be represented by 1 bit, and Nack may be
represented by a plurality of bits. Information on the CBGs having
reception errors may be represented by using the plurality of bits.
Consequently, the bits remaining in transmitting the Ack can carry
the other information.
[1000] The UE may transmit, to the gNB, the HARQ feedback in
response to the downlink communication using, for example, the
PUCCH. With regard to the PUCCH, the UE may transmit the HARQ
feedback using, for example, physical resources in a frequency
direction. Alternatively, the UE may transmit the feedback using,
for example, the MAC control information. Since application of the
MAC control information enables multi-level modulation, the
transmission is possible with less physical resources.
[1001] When the MAC control information is used, the gNB may notify
the UE of a grant for transmitting the feedback. Alternatively, the
UE may transmit the feedback using, for example, a new channel.
When transmitting the MAC control information, the UE may perform
the HARQ feedback as when transmitting the uplink user data.
[1002] The UE may transmit, to the gNB, the HARQ feedback in
response to the uplink communication using, for example, the L1/L2
signaling. Alternatively, the structure of the Enhanced Physical
Downlink Control Channel (EPDCCH) may be used. Alternatively,
information on the CBG with NG may be placed somewhere in the same
subframe. Alternatively, the MAC control information may be used.
Since application of the MAC control information enables
multi-level modulation, information with more bits can be fed back.
When transmitting the MAC control information, the UE may perform
the HARQ feedback similarly as when transmitting the downlink user
data. Alternatively, the gNB may transmit the HARQ feedback to the
UE using, for example, the PHICH.
[1003] Similarly as the first embodiment, the gNB may include the
feedback information in response to the uplink communication in an
uplink grant for the UE. Alternatively, the gNB may not notify the
UE of Ack feedback. The UE may regard the absence of receiving the
HARQ feedback on the uplink data for a predefined time as accurate
reception of the uplink data by the gNB. Alternatively, the method
for including the feedback information in the uplink grant may be
used in combination with the method for preventing notification of
Ack feedback to the UE. Consequently, the UE does not have to
receive the grant from the gNB even when finishing transmitting the
uplink user data, and can know that the gNB has successfully
received the last uplink user data. Since the gNB need not notify
the UE of the HARQ feedback information in response to the last
uplink user data, the communication resources are saved.
[1004] Alternatively, a plurality of methods for the HARQ feedback
in each of the downlink communication and the uplink communication
may be used in combination. For example, in the HARQ feedback in
the downlink communication, the UE may notify the gNB of the
presence or absence of a reception error using the PUCCH and of the
CBG number to which the code block including the reception error
belongs, using the MAC control information. Consequently, the
reliability of the HARQ feedback can be increased.
[1005] Information on the CBG including the code block having the
reception error may be transmitted as a detail of the HARQ feedback
according to the ninth embodiment. Examples of the information may
include the CBG number and the number of CBGs. Alternatively, the
information may be transmitted as, for example, a bitmap indicating
whether the CBG can be received or indicating an error. Assume the
bitmap where, for example, the number of CBGs is 4, 1 is associated
with a CBG with a reception error, and 0 is associated with a CBG
without a reception error. When a code block belonging to the CBG
#3 has a reception error, the bit string that the gNB will feed
back to the UE may be "0010".
[1006] In grouping the CBGs according to the ninth embodiment,
there may be a code block belonging to a plurality of CBGs. For
example, code blocks to be mapped to each symbol may be grouped
into one CBG. Consequently, when, for example, communication with
higher priority, e.g., communication requiring the URLLC service
interrupts a given symbol, the receiver feeds back information on
the CBG corresponding to the symbol to the transmitter, so that the
transmitter can retransmit the code blocks mapped to the
symbol.
[1007] The code blocks to be mapped to a plurality of symbols may
be grouped into one CBG. Consequently, the number of bits required
for the HARQ feedback can be reduced to small.
[1008] The associations between code blocks and CBGs in the
grouping may be predefined in a standard. Alternatively, the gNB
may notify the UE of the associations. Information on the
associations may be, for example, the numbers of the first code
block and the last code block belonging to each of the CBGs. The
notification may be semi-statically made via the RRC-dedicated
signaling.
[1009] The receiver may notify the transmitter of a reception error
of a code block belonging to a plurality of CBGs, as a CBG
including another code block having a reception error among the
plurality of CBGs. Alternatively, the receiver may notify the
transmitter of the reception error as a CBG with a preceding number
or as a CBG with a subsequent number among the plurality of CBGs.
The notification of the reception error as a CBG including another
code block having a reception error can reduce the number of CBGs
to be fed back.
[1010] Alternatively, the receiver may notify the transmitter of a
symbol number including the code block having a reception error.
Since the gNB need not notify the UE of the associations between
code blocks and CBGs in advance, the amount of signaling can be
reduced. A plurality of symbols may be integrated into one group,
and the receiver may feed back an identifier indicating the group
to the transmitter.
[1011] FIG. 30 illustrates associations between code blocks and a
plurality of CBGs when the code blocks belong to the plurality of
CBGs. FIG. 30 illustrates a case where the code blocks to be mapped
to one symbol are grouped into one CBG in the downlink
communication.
[1012] Since a code block #h (CB #h), a code block # (h+1) (CB #
(h+1)), and a code block # (k-1) (CB # (k-1)) that belong to the
symbol #2, that is, the CBG #2 have reception errors in FIG. 30,
the UE performs, on the gNB, HARQ feedback to indicate that the CBG
#2 has the reception errors. The gNB retransmits, to the UE, the
code block #h (CB #h) to the code block #k (CB #k) using the HARQ
feedback.
[1013] Notification of information on consecutive code blocks (may
be hereinafter referred to as a "code block cluster") including a
code block having a reception error may replace the grouping of
CBGs, according to the ninth embodiment. The code block cluster may
include a code block where the reception result has been OK.
[1014] The receiver finds the code block cluster from a reception
result of each code block. The receiver includes information on the
code block cluster in the HARQ feedback information to notify the
transmitter of the information. The transmitter retransmits, to the
receiver, code blocks belonging to the code block cluster.
[1015] The information on the code block cluster may be information
indicating the first code block or information indicating the last
code block. Alternatively, the information on the code block
cluster may be information indicating the number of code blocks.
Alternatively, at least two of these may be used in
combination.
[1016] The information indicating the first code block may be, for
example, the first code block number, or a value obtained by
dividing the code block number by a predetermined constant. The
value may be obtained by truncating the decimal places. The
constant may be defined in a standard, or notified from the gNB to
the UE via the RRC-dedicated signaling in advance. Alternatively,
the receiver may determine the constant and notify it to the
transmitter. The receiver may dynamically make the notification.
The dynamic notification may be made, for example, using the MAC
control information or via the L1/L2 signaling. Consequently, the
receiver can transmit the HARQ feedback to the transmitter with
less number of bits, according to a state in which the reception
error occurs. The gNB may dynamically notify the UE of the
constant.
[1017] Application of the value obtained by dividing the first code
block number by the constant can reduce the number of bits for the
HARQ feedback. The information indicating the last code block may
be handled similarly as the information indicating the first code
block.
[1018] The information indicating the number of code blocks may be
handled similarly as the information indicating the first code
block. Alternatively, the number of code blocks may be rounded to a
value of a power of a predefined integer, and a value of the
exponent of the power may be used. The value of the power is
preferably larger than or equal to the number of code blocks. The
integer may be defined in a standard, or notified from the gNB to
the UE via the RRC-dedicated signaling in advance.
[1019] Alternatively, the receiver may determine the integer and
notify it to the transmitter. The receiver may dynamically make the
notification. The dynamic notification may be made, for example,
using the MAC control information or via the L1/L2 signaling.
Consequently, the receiver can transmit the HARQ feedback to the
transmitter with less number of bits, according to a state in which
the reception error occurs. The gNB may dynamically notify the UE
of the integer.
[1020] FIG. 31 illustrates a relationship between a code block
cluster and consecutive code blocks including reception errors. In
FIG. 31, a code block #2 (CB #2), and a code block #4 (CB #4) to a
code block #6 (CB #6) have the reception errors.
[1021] In FIG. 31, assuming a code block #3 (CB #3) where the
reception result has been OK as having a reception error, the
receiver notifies the transmitter that the code block #2 (CB #2) to
the code block #6 (CB #6) have the reception errors. In the
notification, the receiver may notify the transmitter of
identifiers of the code block #2 (CB #2) and the code block #6 (CB
#6), or information indicating the identifier of the code block #2
(CB #2) and the number of reception errors. In FIG. 31, the number
of reception errors to be notified from the receiver to the
transmitter is 5.
[1022] The transmitter obtains information on the code blocks
having the reception errors, from the notification. The transmitter
retransmits, to the receiver, the code block #2 (CB #2) to the code
block #6 (CB #6).
[1023] Notification of information on the code block cluster from
the receiver to the transmitter can reduce, to small, information
on the HARQ feedback to be notified from the receiver to the
transmitter when the code blocks having the reception errors are
consecutive or slightly apart, particularly when the code blocks
having the reception errors straddle a boundary of CBGs.
[1024] The CBGs may replace the code blocks in notification of the
information on the code block cluster according to the ninth
embodiment. In the HARQ feedback from the receiver to the
transmitter, for example, the first CBG number including the
reception error and the number of CBGs may be used. Consequently,
information on the HARQ feedback to be notified from the receiver
to the transmitter can be further reduced to small.
[1025] A predefined pattern may be used for the feedback from the
receiver to the transmitter, according to the ninth embodiment. The
predefined pattern may be, for example, a pattern in which the
first quarter and the last quarter of the whole code blocks in a
transport block have reception errors. The predefined pattern may
be, for example, a pattern in which the first quarter to the last
quarter of the code blocks have reception errors, or a pattern in
which the first one-eighth and the last one-eighth of the code
blocks have reception errors.
[1026] The predefined pattern may not be symmetrical. The
predefined pattern may be a pattern in which among the whole code
blocks in a transport block, for example, the first 5 code blocks
have reception errors or the first 3 code blocks and the fifth and
the seventh code blocks from the beginning have reception
errors.
[1027] Alternatively, the predefined pattern may be a pattern
corresponding to, in a physical channel, a symbol number of each
symbol to which a code block having a reception error is
mapped.
[1028] A list of predefined patterns may be defined in a standard,
or notified from the gNB to the UE in advance. The list of the
predefined patterns may include a pattern of Ack, that is, a
pattern in which no code block has a reception error.
[1029] The list of the predefined patterns may include a pattern in
which no code block has a reception error. The gNB and the UE may
use the pattern in notification of accurate receipt of all the code
blocks.
[1030] The receiver determines a pattern for feeding back to the
transmitter, using a reception result of each code block. In the
list of the predefined patterns, the pattern preferably includes
all the code blocks having reception errors. The receiver notifies
the transmitter of an identifier indicating the pattern. The
transmitter retransmits, to the receiver, a code block having the
reception error in the pattern indicated by the identifier.
[1031] FIG. 32 illustrates patterns of code blocks including
reception errors. FIG. 32 illustrates a case where received data
includes reception errors 3302, 3304, and 3305. In FIG. 32,
portions excluding the reception errors 3302, 3304, and 3305, for
example, portions denoted by references 3301, 3303, and 3306 are
portions that have successfully been received without any reception
error.
[1032] Upon detection of the reception errors 3302, 3304, and 3305
as indicated in the received data in FIG. 32, the receiver feeds
back an identifier indicating a pattern #4 to the transmitter. The
transmitter retransmits, to the receiver, the code block #1 (CB #1)
to the code block #5 (CB #5) according to the pattern #4.
[1033] Notification of information on the code block cluster from
the receiver to the transmitter can reduce, to small, information
on the HARQ feedback to be notified from the receiver to the
transmitter, even when the code blocks having the reception errors
are distributed in a transport block.
[1034] The gNB may switch between levels of the HARQ feedback,
according to the ninth embodiment. Examples of the HARQ levels may
include feedback for each code block, feedback for each CBG, and
feedback on the whole transport block. The feedback for each CBG
may have a plurality of levels. The feedback for each CBG may have,
for example, a level of feedback to be performed by CBGs with less
number of code blocks per CBG, and a level of feedback to be
performed by CBGs with larger number of code blocks per CBG. With
regard to the number of code blocks in each level, the number of
code blocks included in a CBG to be used in a given level may or
may not be an integer multiple of the number of code blocks
included in a CBG to be used in another level. In the given level,
a plurality of CBGs may or may not include the same code block.
[1035] The gNB notifies the UE of the feedback levels. The details
to be notified may be details of the feedback levels, for example,
the number of code blocks per CBG or identifiers of the levels. A
list of the feedback levels may be defined in a standard, or
notified from the gNB to the UE in advance so that the identifiers
are used. The notification may be made via, for example, the RRC
signaling.
[1036] The following (1) to (5) will be disclosed as a method for
the gNB to notify the HARQ feedback level;
[1037] (1) broadcasting to the UEs being served thereby;
[1038] (2) the control signaling for each UE, for example, the
RRC-dedicated signaling for each UE;
[1039] (3) the MAC control information;
[1040] (4) the L1/L2 signaling; and
[1041] (5) combinations of (1) to (4) above.
[1042] Since application of (1) enables simultaneous notification
to a plurality of UEs, the amount of signaling can be reduced.
[1043] Application of (2) enables semi-static setting to each UE.
For example, when a UE using the URLLC service is connected under
the gNB, the HARQ feedback level can be switched for a UE using the
eMBB service from a feedback level of the whole transport block to
a feedback level for each symbol. Consequently, when the UE using
the URLLC service interrupts a symbol to be used by the UE using
the eMBB service, the UE can feed back the symbol number to the
gNB, and the transmission efficiency for the UE using the eMBB
service can be increased.
[1044] With application of (3), the level can be switched according
to dynamic changes in a propagation environment, etc. with high
reliability. Since application of the MAC control information
enables multi-level modulation, the number of bits to be used for
the notification can be reduced to small.
[1045] Application of (4) enables prompt switching of the level
corresponding to dynamic changes in a propagation environment, etc.
even when there is no user data.
[1046] In grouping the CBGs according to the ninth embodiment, a
series of CBG numbers may be allocated to a plurality of HARQ
feedback levels. For example, after the CBG numbers configured with
the predefined maximum number of code blocks are allocated to the
whole code blocks in a transport block, CBG numbers configured with
the maximum number of code blocks larger than the predefined
maximum number of code blocks may be allocated thereto.
[1047] The receiver may determine which CBG number allocated to
which level is used, according to the distribution of code blocks
having the reception errors. The receiver may feed back, to the
transmitter, the CBG number determined by the receiver.
[1048] For example, in a transport block consisting of 20 code
blocks, the gNB and the UE may allocate, using a CBG whose maximum
number of code blocks is 3, the CBG #1 to the code blocks #1 to #3
and the CBG #2 to the code blocks #4 to #6, similarly to the
following code blocks, and finally allocate the CBG #6 to the code
blocks #15 to #18, and the CBG #7 to the code blocks #19 and #20.
Alternatively, the gNB and the UE may allocate, using a CBG whose
maximum number of code blocks is 5, the CBG #7 to the code blocks
#1 to #5 and the CBG #8 to the code blocks #6 to #10, similarly to
the following code blocks, and finally allocate the CBG #10 to the
code blocks #16 to #20.
[1049] When the receiver have reception errors in the code blocks
#3 and #4 in the example, the receiver may feed back to the
transmitter that the CBG #7 has the reception errors.
[1050] Since the gNB need not notify the UE of the HARQ feedback
level, the amount of signaling from the gNB to the UE can be
reduced.
[1051] In the HARQ feedback according to the ninth embodiment, the
receiver may feed back, to the transmitter, information on the code
block where the reception result has been OK. The receiver may feed
back information on the CBG consisting of only the code blocks
where the reception results have been OK. The receiver may include,
in the feedback, an identifier indicating, as the feedback, that
the reception result has been OK or indicating a reception
error.
[1052] The receiver may determine which one of the feedbacks, i.e.,
indicating that the reception result has been OK or a reception
error the receiver itself will perform, using the number of code
blocks having the reception errors, information on the number of
CBGs, or the number of bits required to feed back that the
reception result has been OK or the reception error.
[1053] Consequently, the receiver can perform feedback to the
transmitter with less number of bits, according to a reception
result of a transport block.
[1054] The following (1) to (5) will be disclosed as information to
be used by the gNB to determine the HARQ feedback level;
[1055] (1) a propagation environment, for example, the CQI/CSI;
[1056] (2) a load in the downlink communication, for example,
buffer occupancy in the gNB;
[1057] (3) a load in the uplink communication, for example, buffer
occupancy in the UE;
[1058] (4) information on the UE, for example, a UE category or a
use service of the UE; and
[1059] (5) combinations of (1) to (4) above.
[1060] In (1), for example, when the CQI/CSI is superior, the level
may be switched so that the maximum number of code blocks per CBG
is increased. Consequently, the number of bits of the feedback for
notifying Ack can be reduced.
[1061] In (2), for example, when the buffer occupancy in the gNB is
larger, reduction in the maximum number of code blocks per CBG can
reduce the overhead incurred by retransmission of the code block
where the reception result has been OK in the feedback of the CBG
having the reception error in the downlink communication. This can
increase the transmission efficiency in the downlink
communication.
[1062] In (3), the Buffer Status Report (BSR) to be notified from
the UE to the gNB or another value may be used.
[1063] In (3), for example, when the buffer occupancy in the UE is
larger, reduction in the maximum number of code blocks per CBG can
reduce the overhead incurred by retransmission of the code block
where the reception result has been OK in the feedback of the CBG
having the reception error in the uplink communication. This can
increase the transmission efficiency in the uplink
communication.
[1064] In (4), for example, reduction in the maximum number of code
blocks per CBG for the UE using the eMBB can reduce the overhead
incurred by retransmission of the code block where the reception
result has been OK in the feedback of the CBG having the reception
error. This can increase the transmission efficiency of the UE
using the eMBB.
[1065] The receiver may assume that all the code blocks have
reception errors, using a predefined threshold, according to the
ninth embodiment. The receiver may notify the transmitter that all
the code blocks have reception errors. The transmitter may
retransmit all the code blocks. The transmitter may exclude, from
the retransmission, the code blocks that have already successfully
been received. The code blocks that have already successfully been
received may be obtained by the feedback from the receiver.
[1066] The predefined threshold may be determined in a standard, or
notified from the gNB to the UE.
[1067] The threshold may be determined using the number of code
blocks having reception errors, the number of CBGs including the
code blocks having reception errors, or the number of bits that can
be used for the HARQ feedback from the receiver. For example, when
the number of bits is 2 and the code blocks having reception errors
straddle the center of the transport block, the receiver may notify
the transmitter of all the code blocks as reception errors.
Consequently, the number of bits of the feedback for notifying the
transmitter of the reception errors can be reduced.
[1068] The maximum number of times a CBG, a code block cluster, or
a pattern of code blocks is retransmitted may be the same as the
maximum number of HARQ retransmissions, according to the ninth
embodiment. In other words, the retransmission according to the
ninth embodiment may be assumed as the HARQ retransmission. Thus,
the implementation of the gNB and the UE can be facilitated.
[1069] The receiver may discard and receive again the code block
where the reception result has been OK, according to the ninth
embodiment. The transmitter may retransmit the code block where the
reception result in the receiver has been OK. The transmitter may
retransmit the code block when the maximum number of HARQ
retransmissions is exceeded.
[1070] Upon completion of a data unit of an upper layer, for
example, an RLC layer, e.g., the RLC PDU, the receiver may transmit
received data to the upper layer, according to the ninth
embodiment. The received data may be data some of whose code blocks
are accurately received in a transport block. This can reduce the
latency in transmitting and receiving the data.
[1071] The receiver may obtain, from the transmitter, the size of
the MAC header, and the size of the data unit of the upper layer in
advance. Alternatively, the sizes may be determined in a
standard.
[1072] The transmitter may add a parity check bit to each CBG,
according to the ninth embodiment. The parity check bit may be, for
example, the CRC. The parity check bit for each CBG and the parity
check bit for the whole transport block may coexist.
[1073] The gNB may notify the UE of whether the parity check bit
for each CBG is used. The notification may be made semi-statically
via the RRC-dedicated signaling or dynamically via the L1/L2
signaling. Alternatively, whether the parity check bit for each CBG
is used may be determined in a standard.
[1074] FIG. 33 illustrates the assignment of parity checks 3401 to
3404 to the respective CBGs. In FIG. 33, the transmitter calculates
a parity bit based on code blocks #1 to #k included in the CBG #1,
and assigns the parity check 3401 to the code block #1 (CB #1).
Similarly in the CBG #2 and the subsequent CBGs, the transmitter
assigns the parity checks 3402, 3403, and 3404 to the code block
#k+1 (CB # (k+1)), . . . the code block #2k+1 (CB # (2k+1)), . . .
the code block # (N-1) k+1 (CB # ((N-1) k+1)), respectively.
[1075] Application of the method can increase the reliability of
the parity checks in the whole transport block.
[1076] Since the receiver can feed back information on the code
blocks having the reception errors with less number of bits
according to the ninth embodiment, the communication can be
efficiently performed.
[1077] The embodiments and the modifications are merely
illustrations of the present invention, and can be freely combined
within the scope of the present invention. Any constituent elements
of the embodiments and the modifications can be appropriately
modified or omitted.
[1078] A subframe is an example time unit in communication in the
fifth-generation base station communication system in the
embodiments and the modifications. The example time unit may be the
unit of scheduling. The process described per subframe may be
performed per TTI, per slot, per sub-slot, or per mini-slot in the
embodiments and the modifications.
[1079] While the invention has been described in detail, the
foregoing description is in all aspects illustrative and not
restrictive. It is therefore understood that numerous modifications
and variations can be devised without departing from the scope of
the invention.
DESCRIPTION OF REFERENCES
[1080] 701 coverage of macro cell, 702 coverage of small cell, 703,
813 user equipment (UE), 801 downlink beam sweeping block, 802,
804, 806, 811 resources, 803 uplink beam sweeping block, 805 DL/UL
data subframe, 812 beam, 901, 905, 909 subframe, 902, 906, 910
downlink control signal, 903, 907, 911 a piece of user data, 904,
908, 912 information on the next reception timing.
* * * * *
References