U.S. patent application number 17/536738 was filed with the patent office on 2022-03-17 for method and apparatus for reporting selected plmn of rrc-inactive mode ue in next-generation communication system.
The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Anil AGIWAL, Jaehyuk JANG, Sangyeob JUNG, Soenghun KIM, Alexander SAYENKO.
Application Number | 20220086723 17/536738 |
Document ID | / |
Family ID | 1000005997017 |
Filed Date | 2022-03-17 |
United States Patent
Application |
20220086723 |
Kind Code |
A1 |
JUNG; Sangyeob ; et
al. |
March 17, 2022 |
METHOD AND APPARATUS FOR REPORTING SELECTED PLMN OF RRC-INACTIVE
MODE UE IN NEXT-GENERATION COMMUNICATION SYSTEM
Abstract
The present disclosure relates to a communication method and
system for converging a 5th-Generation (5G) communication system
for supporting higher data rates beyond a 4th-Generation (4G)
system with a technology for Internet of Things (IoT). The present
disclosure may be applied to intelligent services based on the 5G
communication technology and the IoT-related technology, such as
smart home, smart building, smart city, smart car, connected car,
health care, digital education, smart retail, security and safety
services. The method by a user equipment (UE) in a wireless
communication system includes reselecting another equivalent public
land mobile network (PLMN) in an inactive state, transmitting, to a
base station, a radio resource control (RRC) resume request message
including a resume cause configured to mobile originated
(mo)-signaling in case that a radio access network (RAN)-based
notification area update procedure is triggered, and receiving,
from the base station, an RRC resume message.
Inventors: |
JUNG; Sangyeob; (Suwon-si,
KR) ; AGIWAL; Anil; (Suwon-si, KR) ; JANG;
Jaehyuk; (Suwon-si, KR) ; SAYENKO; Alexander;
(Suwon-si, KR) ; KIM; Soenghun; (Suwon-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Family ID: |
1000005997017 |
Appl. No.: |
17/536738 |
Filed: |
November 29, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16573003 |
Sep 17, 2019 |
11190996 |
|
|
17536738 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 76/27 20180201;
H04W 36/0011 20130101; H04W 36/14 20130101 |
International
Class: |
H04W 36/14 20060101
H04W036/14; H04W 76/27 20060101 H04W076/27; H04W 36/00 20060101
H04W036/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 18, 2018 |
KR |
10-2018-0111639 |
Claims
1. A method performed by a user equipment (UE) in a communication
system, the method comprising: receiving, from a base station, a
radio resource control (RRC) release message; entering an inactive
state based on the RRC release message; reselecting a cell
belonging to an equivalent public land mobile network (PLMN)
associated with a shared network; transmitting, to the base
station, an RRC resume request message including a resume cause
configured to mobile originated (mo)-signaling; receiving, from the
base station, an RRC resume message as a response to the RRC resume
request message; and transmitting, to the base station, an RRC
resume complete message as a response to the RRC resume message,
the RRC resume complete message including a non-access stratum
(NAS) protocol data unit (PDU) and an identifier of a reselected
PLMN.
2. The method of claim 1, wherein the resume cause is configured to
mo-signaling based on reselection of the cell belonging to the
equivalent PLMN associated with the shared network, in case that a
radio access network (RAN)-based notification area update procedure
is triggered.
3. The method of claim 1, wherein the RRC release message includes
suspend configuration information.
4. The method of claim 2, wherein the RAN-based notification area
update procedure is triggered in case that the UE is located in a
RAN-based notification area which is not included in RAN indication
area information configured to the UE.
5. A method performed by a base station in a communication system,
the method comprising: transmitting, to a user equipment (UE), a
radio resource control (RRC) release message; in case that a cell
belonging to an equivalent public land mobile network (PLMN)
associated with a shared network is reselected by the UE,
receiving, from the UE, an RRC resume request message including a
resume cause configured to mobile originated (mo)-signaling;
transmitting, to the UE, an RRC resume message as a response to the
RRC resume request message; and receiving, from the UE, an RRC
resume complete message as a response to the RRC resume message,
the RRC resume complete message including a non-access stratum
(NAS) protocol data unit (PDU) and an identifier of a reselected
PLMN.
6. The method of claim 5, wherein the resume cause is configured to
mo-signaling based on reselection of the cell belonging to the
equivalent PLMN associated with the shared network, in case that a
radio access network (RAN)-based notification area update procedure
is triggered.
7. The method of claim 5, wherein the RRC release message includes
suspend configuration information..
8. The method of claim 6, wherein the RAN-based notification area
update procedure is triggered in case that the UE is located in a
RAN-based notification area which is not included in RAN
notification area information configured for the UE.
9. A user equipment (UE) in a communication system, the UE
comprising: a transceiver; and at least one processor coupled with
the transceiver and configured to: receive, from a base station, a
radio resource control (RRC) release message, enter an inactive
state based on the RRC release message, reselect a cell belonging
to an equivalent public land mobile network (PLMN) associated with
a shared network, transmit, to the base station, an RRC resume
request message including a resume cause configured to mobile
originated (mo)-signaling, receive, from the base station, an RRC
resume message as a response to the RRC resume request message, and
transmit, to the base station, an RRC resume complete message as a
response to the RRC resume message, the RRC resume complete message
including a non-access stratum (NAS) protocol data unit (PDU) and
an identifier of a reselected PLMN.
10. The UE of claim 9, wherein the resume cause is configured to
mo-signaling based on reselection of the cell belonging to the
equivalent PLMN associated with the shared network, in case that a
radio access network (RAN)-based notification area update procedure
is triggered.
11. The UE of claim 9, wherein the RRC release message includes
suspend configuration information.
12. The UE of claim 10, wherein the RAN-based notification area
update procedure is triggered in case that the UE is located in a
RAN-based notification area which is not included in RAN indication
area information configured to the UE.
13. A base station in a communication system, the base station
comprising: a transceiver; and at least one processor coupled with
the transceiver and configured to: transmit, to a user equipment
(UE), a radio resource control (RRC) release message, in case that
a cell belonging to an equivalent public land mobile network (PLMN)
associated with a shared network is reselected by the UE, receive,
from the UE, an RRC resume request message including a resume cause
configured to mobile originated (mo)-signaling, transmit, to the
UE, an RRC resume message as a response to the RRC resume request
message, and receive, from the UE, an RRC resume complete message
as a response to the RRC resume message, the RRC resume complete
message including a non-access stratum (NAS) protocol data unit
(PDU) and an identifier of a reselected PLMN.
14. The base station of claim 13, wherein the resume cause is
configured to mo-signaling based on reselection of the cell
belonging to the equivalent PLMN associated with the shared
network, in case that a radio access network (RAN)-based
notification area update procedure is triggered, and wherein the
RRC release message includes suspend configuration information.
15. The base station of claim 13, wherein the RAN-based
notification area update procedure is triggered in case that the UE
is located in a RAN-based notification area which is not included
in RAN notification area information configured for the UE.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is is a continuation application of prior
application Ser. No. 16/573,003 filed on Sep. 17, 2019, which
issued as U.S. Pat. No. 11,190,996 on Nov. 30, 2021, which is based
on and claims priority under 35 U.S.C. 119 of a Korean patent
application number 10-2018-0111639, filed on Sep. 18, 2018, in the
Korean Intellectual Property Office, the disclosure of which is
incorporated by reference herein in its entirety.
BACKGROUND
1. Field
[0002] The disclosure relates to operation of a user equipment (UE)
and a base station in a next-generation wireless communication
system
2. Description of Related Art
[0003] Aspects of the disclosure are to address at least the
above-mentioned problems and/or disadvantages and to provide at
least the advantages described below. Accordingly, an aspect of the
disclosure is to meet the demand for wireless data traffic having
increased since deployment of 4.sup.th-Generation (4G)
communication systems, efforts have been made to develop an
improved 5.sup.th Generation (5G) or pre-5G communication system.
Therefore, the 5G or pre-5G communication system is also called a
`Beyond 4G Network` or a `Post LTE System`. The 5G communication
system is considered to be implemented in higher frequency (mmWave)
bands, e.g., 60 GHz bands, so as to accomplish higher data rates.
To decrease propagation loss of the radio waves and increase the
transmission distance, the beamforming, massive multiple-input
multiple-output (MIMO), Full Dimensional MIMO (FD-MIMO), array
antenna, an analog beam forming, large scale antenna techniques are
discussed in 5G communication systems. In addition, in 5G
communication systems, development for system network improvement
is under way based on advanced small cells, cloud Radio Access
Networks (RANs), ultra-dense networks, device-to-device (D2D)
communication, wireless backhaul, moving network, cooperative
communication, Coordinated Multi-Points (CoMP), reception-end
interference cancellation and the like. In the 5G system, Hybrid
FSK and QAM Modulation (FQAM) and sliding window superposition
coding (SWSC) as an advanced coding modulation (ACM), and filter
bank multi carrier (FBMC), non-orthogonal multiple access (NOMA),
and sparse code multiple access (SCMA) as an advanced access
technology have been developed.
[0004] The Internet, which is a human centered connectivity network
where humans generate and consume information, is now evolving to
the Internet of Things (IoT) where distributed entities, such as
things, exchange and process information without human
intervention. The Internet of Everything (IoE), which is a
combination of the IoT technology and the Big Data processing
technology through connection with a cloud server, has emerged. As
technology elements, such as "sensing technology", "wired/wireless
communication and network infrastructure", "service interface
technology", and "Security technology" have been demanded for IoT
implementation, a sensor network, a Machine-to-Machine (M2M)
communication, Machine Type Communication (MTC), and so forth have
been recently researched. Such an IoT environment may provide
intelligent Internet technology services that create a new value to
human life by collecting and analyzing data generated among
connected things. IoT may be applied to a variety of fields
including smart home, smart building, smart city, smart car or
connected cars, smart grid, health care, smart appliances and
advanced medical services through convergence and combination
between existing Information Technology (IT) and various industrial
applications.
[0005] In line with this, various attempts have been made to apply
5G communication systems to IoT networks. For example, technologies
such as a sensor network, Machine Type Communication (MTC), and
Machine-to-Machine (M2M) communication may be implemented by
beamforming, MIMO, and array antennas. Application of a cloud Radio
Access Network (RAN) as the above-described Big Data processing
technology may also be considered to be as an example of
convergence between the 5G technology and the IoT technology.
[0006] The above information is presented as background information
only to assist with an understanding of the disclosure. No
determination has been made, and no assertion is made, as to
whether any of the above might be applicable as prior art with
regard to the disclosure.
SUMMARY
[0007] An aspect of the disclosure is to provide a method of
reducing power consumption of the UE when 3GPP 5G new radio (NR)
technology is used in an unlicensed band in a wireless
communication system.
[0008] Another aspect of the disclosure is to provide a method by
which an RRC-inactive mode UE reports a selected PLMN.
[0009] In accordance with another aspect of the disclosure, a
method by a user equipment (UE) in a wireless communication system
is provided. The method includes reselecting another equivalent
public land mobile network (PLMN) by an inactive-state UE,
transmitting, to a base station, a radio resource control (RRC)
resume request message including a resume cause configured to
mobile originated (mo)-signaling in case that a radio access
network (RAN)-based notification area update procedure is
triggered, and receiving, from the base station, an RRC resume
message.
[0010] In accordance with another aspect of the disclosure, a
method by a base station in a wireless communication system is
provided. The method includes in case that another equivalent
public land mobile network (PLMN) is reselected by an
inactive-state user equipment (UE) and a radio access network
(RAN)-based notification area update procedure is triggered,
receiving, from a user equipment (UE), a radio resource connection
(RRC) resume request message including a resume cause configured to
mobile originated (mo)-signaling, and transmitting, to the UE, an
RRC resume message.
[0011] In accordance with another aspect of the disclosure, a user
equipment (UE) in a wireless communication system is provided. The
UE includes a transceiver, and at least one processor coupled with
the transceiver and configured to reselect another equivalent
public land mobile network (PLMN) in an inactive state, control the
transceiver to transmit, to a base station, a radio resource
control (RRC) resume request message including a resume cause
configured to mobile originated (mo)-signaling in case that a radio
access network (RAN)-based notification area update procedure is
triggered, and control the transceiver to receive, from the base
station, an RRC resume message.
[0012] In accordance with another aspect of the disclosure, a base
station in a wireless communication system is provided. The base
station includes a transceiver, and at least one processor coupled
with the transceiver and configured to: in case that another
equivalent public land mobile network (PLMN) is reselected by an
inactive-state user equipment (UE) and a radio access network
(RAN)-based notification area update procedure is triggered,
control the transceiver to receive, from a UE, a radio resource
connection (RRC) resume request message including a resume cause
configured to mobile originated (mo)-signaling, and control the
transceiver to transmit, to the UE, an RRC resume message.
[0013] Through the disclosure, the UE can discontinuously receive
signals from a base station while communicating with the gNB using
a broadband frequency, thereby reducing power consumption of the
UE.
[0014] Further, through the disclosure, an RRC-inactive mode UE can
efficiently report a selected PLMN.
[0015] Other aspects, advantages, and salient features of the
disclosure will become apparent to those skilled in the art from
the following detailed description, which, taken in conjunction
with the annexed drawings, discloses various embodiments of the
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and other aspects, features, and advantages of
certain embodiments of the disclosure will be more apparent from
the following description taken in conjunction with the
accompanying drawings, in which:
[0017] FIG. 1A illustrates a structure of an LTE system for
reference to describe according to an embodiment of the
disclosure;
[0018] FIG. 1B illustrates a wireless protocol structure in LTE and
NR systems for reference to describe according to an embodiment of
the disclosure;
[0019] FIG. 1C illustrates an example of downlink and uplink
channel frame structures in beam-based communication of an NR
system according to an embodiment of the disclosure;
[0020] FIG. 1D illustrates LBT type 1 method according to an
embodiment of the disclosure;
[0021] FIG. 1E illustrates LBT type 2 method according to an
embodiment of the disclosure;
[0022] FIG. 1F illustrates DRB operation of NR according to an
embodiment of the disclosure;
[0023] FIG. 1G illustrates a first DRX operation used by a UE
operating in an unlicensed band according to an embodiment of the
disclosure;
[0024] FIG. 1H illustrates the operation order of the UE when the
first DRX operation used by the UE operating in the unlicensed band
is performed according to an embodiment of the disclosure;
[0025] FIG. 1I illustrates a second DRX operation used by the UE
operating in the unlicensed band according to an embodiment of the
disclosure;
[0026] FIG. 1J illustrates the operation order of the UE when the
second DRX operation used by the UE operating in the unlicensed
band is performed according to an embodiment of the disclosure;
[0027] FIG. 1K is a block diagram of the UE in a wireless
communication system according to an embodiment of the
disclosure;
[0028] FIG. 1L illustrates a structure of an eNB according to an
embodiment of the disclosure;
[0029] FIG. 2A illustrates a structure of an LTE system according
to an embodiment of the disclosure;
[0030] FIG. 2B illustrates a wireless protocol structure in an LTE
system according to an embodiment of the disclosure;
[0031] FIG. 2C illustrates a structure of a next-generation mobile
communication system according to an embodiment of the
disclosure;
[0032] FIG. 2D illustrates a wireless protocol structure of a
next-generation mobile communication system according to an
embodiment of the disclosure;
[0033] FIG. 2E illustrates a procedure in which a base station
releases a connection of a UE and thus the UE switches from an
RRC-connected mode to an RRC-idle mode and a procedure in which the
UE configures the connection with the base station and thus
switches from the RRC-idle mode to the RRC-connected mode according
to an embodiment of the disclosure;
[0034] FIG. 2F illustrates a procedure in which the base station
releases the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the base station and thus
switches from the RRC-inactive mode to the RRC-connected mode
according to an embodiment of the disclosure.
[0035] FIG. 2G illustrates a procedure in which the base station
releases the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the base station and thus
switches from the RRC-inactive mode to the RRC-connected mode
according to an embodiment of the disclosure;
[0036] FIG. 2H illustrates a procedure in which the base station
releases the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the base station and thus
switches from the RRC-inactive mode to the RRC-connected mode
according to an embodiment of the disclosure;
[0037] FIG. 2I is a block diagram illustrating an internal
structure of a UE according to an embodiment of the disclosure;
and
[0038] FIG. 2J is a block diagram illustrating the configuration of
an NR base station according to an embodiment of the
disclosure.
[0039] Throughout the drawings, like reference numerals will be
understood to refer to like parts, components, and structures.
DETAILED DESCRIPTION
[0040] The following description with reference to the accompanying
drawings is provided to assist in a comprehensive understanding of
various embodiments of the disclosure as defined by the claims and
their equivalents. It includes various specific details to assist
in that understanding but these are to be regarded as merely
exemplary. Accordingly, those of ordinary skill in the art will
recognize that various changes and modifications of the various
embodiments described herein can be made without departing from the
scope and spirit of the disclosure. In addition, descriptions of
well-known functions and constructions may be omitted for clarity
and conciseness.
[0041] The terms and words used in the following description and
claims are not limited to the bibliographical meanings, but, are
merely used by the inventor to enable a clear and consistent
understanding of the disclosure. Accordingly, it should be apparent
to those skilled in the art that the following description of
various embodiments of the disclosure is provided for illustration
purpose only and not for the purpose of limiting the disclosure as
defined by the appended claims and their equivalents.
[0042] It is to be understood that the singular forms "a," "an,"
and "the" include plural referents unless the context clearly
dictates otherwise. Thus, for example, reference to "a component
surface" includes reference to one or more of such surfaces.
[0043] For convenience of the description below, the disclosure
uses terms and names defined in LTE and NR standards, which are the
latest standards defined by the 3rd generation partnership project
(3GPP) organization, among the existing communication standards.
However, the disclosure is not limited by the terms and names, and
may be equally applied to systems according to other standards.
Particularly, the disclosure may be applied to 3GPP NR (5th
generation mobile communication standard).
[0044] FIG. 1A illustrates a structure of an LTE system for
reference to describe the disclosure. An NR system has a similar
structure according to an embodiment of the disclosure.
[0045] Referring to FIG. 1A, a wireless communication system
includes a plurality of eNBs 1a-05, 1a-10, 1a-15, and 1a-20, a
mobility management entity (MME) 1a-25, and a serving-gateway
(S-GW) 1a-30. A user equipment (hereinafter, a UE or a terminal)
1a-35 accesses an external network through the eNBs 1a-05, 1a-10,
1a-15, and 1a-20 and the S-GW 1a-30.
[0046] The eNBs 1a-05, 1a-10, 1a-15, and 1a-20 are access nodes of
a cellular network and provide a wireless connection to UEs
accessing the network. That is, the eNBs 1a-05, 1a-10, 1a-15, and
1a-20 perform scheduling by collecting state information, such as
channel states, available transmission power states, and buffer
states of the UEs, to service traffic of users, and support
connection between the UEs and a core network (CN).
[0047] The MME 1a-25 corresponds to a device which is responsible
for various control functions including a mobility management
function for a UE and is connected to a plurality of eNBs, and the
S-GW 1a-30 corresponds to a device which provides a data bearer. In
addition, the MME 1a-25 and the S-GW 1a-30 may further perform
authentication, bearer management, and the like for a UE accessing
a network, and processes a packet arrived from the eNBs 1a-05,
1a-10, 1a-15, and 1a-20 or a packet to be transferred to the eNBs
1a-05, 1a-10, 1a-15, and 1a-20.
[0048] FIG. 1B illustrates a wireless protocol structure in LTE and
NR systems for reference to describe according to an embodiment of
the disclosure.
[0049] Referring to FIG. 1B, in relation to a wireless protocol
structure of an LTE system, each of a UE and an eNB includes a
packet data convergence protocol (PDCP) layer 1b-05 or 1b-40, a
radio link control (RLC) layer 1b-10 or 1b-35, and a medium access
control (MAC) layer 1b-15 or 1b-30. The packet data convergence
protocol (PDCP) layer 1b-05 or 1b-40 is responsible for IP header
compression/decompression, and the radio link control (hereinafter,
referred to as RLC) layer 1b-10 or 1b-35 reconfigures PDCP packet
data units (PDCP PDUs) to a proper size.
[0050] The MAC layer 1b-15 or 1b-30 is connected to several
RLC-layer devices configured in one UE, and performs an operation
of multiplexing RLC PDUs to a MAC PDU and demultiplexing RLC PDUs
from a MAC PDU.
[0051] Physical layers 1b-20 and 1b-25 channel-code and modulate
higher layer data into OFDM symbols and transmit the OFDM symbols
through a wireless channel, or demodulate and channel-decode OFDM
symbols received through the wireless channel to transfer the OFDM
symbols to a higher layer. In addition, for additional error
correction, hybrid ARQ (HARQ) is used in the physical layers, and a
receiver side transmits 1-bit information indicating whether a
packet transmitted by a transmitter side is received. This
information is referred to as HARQ ACK/NACK information. Downlink
HARQ ACK/NACK information for uplink data transmission may be
transmitted through a physical hybrid-ARQ indicator channel (PHICH)
in case of the LTE system. In case of an NR system, it can be
determined whether retransmission is required or new transmission
is enough, through scheduling information of a corresponding UE in
a physical downlink control channel (PDCCH) which is a channel
through which downlink/uplink resource allocation is transmitted.
This is because asynchronous HARQ is applied in the NR system.
[0052] Uplink HARQ ACK/NACK information for downlink data
transmission may be transmitted through a physical uplink control
channel (PUCCH) or a physical uplink shared channel (PUSCH). The
PUCCH is generally transmitted in an uplink resource of a PCell
which is to be described later. However, if there is a support by a
PUCCH, the PUCCH may be additionally transmitted through an SCell
which is to be described later. This SCell is referred to as a
PUCCH SCell.
[0053] Although not illustrated, a radio resource control (RRC)
layer exists above a PDCP layer of each of a UE and an eNB, and the
radio resource control (RRC) layer may transmit and receive an
access- and measurement-related configuration control message to
control radio resources.
[0054] Meanwhile, the PHY layer may include one or a plurality of
frequencies/carriers, and a technique of simultaneously configuring
and using a plurality of frequencies is called a carrier
aggregation technique (hereinafter, referred to as CA). Only one
carrier was used for communication between a terminal (or UE) and
an e-utran nodeB, (eNB) in the past, but the CA technique can
significantly increase the transmission amount as much as the
number of subcarriers by additionally using a main carrier and one
or more subcarriers. Meanwhile, in the LTE system, a cell in an eNB
using a main carrier is referred to as a main cell or a primary
cell (PCell), and a cell in an eNB using a subcarrier is referred
to as a sub-cell or a secondary cell (SCell).
[0055] FIG. 1C illustrates an example of downlink and uplink
channel frame structures in beam-based communication of an NR
system according to an embodiment of the disclosure.
[0056] Referring to FIG. 1C, an eNB1c-01 transmits a signal in the
form of beams 1c-11, 1c-13, 1c-15, and 1c-17 to transmit wider
coverage or a stronger signal. Accordingly, a UE 1c-03 in a cell is
required to transmit and receive data by using a specific beam
(beam #1 1c-13 in FIG. 1C) transmitted by the eNB.
[0057] Meanwhile, depending on whether the UE is connected to the
eNB, the status of the UE is divided into an idle mode (RRC_IDLE)
and a connected mode (RRC_CONNECTED). Accordingly, the eNB does not
recognize location of the UE in the idle mode.
[0058] If the UE in the idle mode is to be shifted to the connected
mode, the UE may receive synchronization signal blocks (SSBs)
1c-21, 1c-23, 1c-25, and 1c-27 transmitted by the eNB. The SSBs are
transmitted periodically according to a cycle configured by the
eNB, and each of the SSBs may include a primary synchronization
signal (PSS) 1c-41, a secondary synchronization signal (SSS) 1c-43,
and a physical broadcast channel (PBCH) 1c-45.
[0059] In FIG. 1C, a scenario in which an SSB is transmitted for
each beam is assumed. For example, it is assumed that SSB #0 1c-21
is transmitted using beam #0 1c-11, SSB #1 1c-23 is transmitted
using beam #1 1c-13, SSB #2 1c-25 is transmitted using beam #2
1c-15, and SSB #3 1c-27 is transmitted using beam #3 1c-17. In FIG.
1C, it is assumed that the UE in the idle mode is located in beam #
1. However, if the UE in the connected mode performs random access,
the UE selects an SSB received at the time of performing random
access.
[0060] Accordingly, in FIG. 1C, the UE receives SSB #1 transmitted
through beam #1. If SSB #1 is received, the UE acquires a physical
cell identifier (PCI) of the eNB through a PSS and an SSS, and
receives a PBCH, so that the UE may identify an identifier (i.e.,
#1) of the currently received SSB, a location at which the SSB is
currently received within a 10 ms frame, and a system frame number
(SFN) having a cycle of 10.24 seconds in which the SSB is located.
In addition, the PBCH may include a master information block (MIB),
and the MIB may include information on where to receive system
information block type 1 (SIB1) for broadcasting more detailed
configuration information of the cell.
[0061] If the SIB1 is received, the UE may identify the total
number of SSBs transmitted by the eNB and may identify location
(assuming a scenario in which a PRACH occasion is allocated every 1
ms in FIG. 1C: 1c-30 to 1c-39) of physical random access channel
(PRACH) occasions in which the UE may perform random access to be
shifted to the connected mode (more precisely, may transmit a
preamble which is a physical signal specifically designed for
uplink synchronization). In addition, the UE may identify a PRACH
occasion among the PRACH occasions and an SSB index, based on the
information, wherein the PRACH occasion is mapped to the SSB index.
For example, in FIG. 1C, a scenario in which a PRACH occasion is
allocated every 1 ms and a scenario in which a halt of an SSB is
allocated per PRACH occasion (that is, two PRACH occasions per SSB)
are assumed. Accordingly, a scenario in which two PRACH occasions
are allocated for each SSB from a PRACH occasion starting according
to an SFN value is illustrated. That is, PRACH occasions 1c-30 and
1c-31 may be allocated for SSB #0, and PRACH occasions 1c-32 and
1c-33 may be allocated for SSB #1. After PRACH occasions are
allocated for all SSBs, PRACH occasions 1c-38 and 1c-39 are
allocated for the first SSB.
[0062] Accordingly, the UE identifies locations of the PRACH
occasions 1c-32 and 1c-33 for SSB #1, and transmits a random access
preamble at the currently earliest PRACH occasion between the PRACH
occasions 1c-32 and 1c-33 corresponding to SSB #1 (for example,
1c-32).
[0063] Since the eNB has received the preamble at the PRACH
occasion 1c-32, it can be seen that the corresponding UE has
transmitted the preamble by selecting SSB #1. Accordingly, data may
be transmitted and received through the corresponding beam when
subsequent random access is performed.
[0064] Meanwhile, when the UE in the connected mode moves from the
current (source) eNB to a target eNB due to handover, etc., the UE
performs random access at the target eNB and selects an SSB as
described above to perform an operation of transmitting a random
access preamble. In addition, during handover, a handover command
is transmitted to the UE to allow the UE to move from the source
eNB to the target eNB. In this case, the message may include a
corresponding UE dedicated random access preamble identifier
allocated to each SSB of the target eNB to enable use of the
identifier when the UE performs random access at the target eNB.
The eNB may not allocate a dedicated random access preamble
identifier for all beams (depending on the current location of the
UE, etc.), and some SSBs may not be allocated a dedicated random
access preamble (for example, allocation of a dedicated random
access preamble to Beam #2 and Beam #3 only).
[0065] If a dedicated random access preamble is not allocated to an
SSB selected by the UE for preamble transmission, the UE randomly
selects a contention-based random access preamble to perform random
access. For example, in FIG. 1C, after the UE is located in Beam #1
and first performs random access but fails, the UE may be located
in Beam #3 to transmit a dedicated preamble when transmitting a
random access preamble again. That is, even in one random access
procedure, if preamble retransmission is performed, a
contention-based random access procedure and a contention-free
random access procedure may be mixed depending on whether a
dedicated random access preamble is allocated to a selected SSB for
each preamble transmission.
[0066] Meanwhile, a scenario in which the UE operates in an
unlicensed band in the above-mentioned 5.sup.th Generation (5G)
system may be considered. The unlicensed band means a frequency
band that anyone can use freely without a separate license in the
regulatory allowance at a corresponding frequency. For example, the
unlicensed band includes a 2.4 GHz, 5 GHz band, or the like, and a
wireless LAN and Bluetooth perform communication by using a
corresponding frequency.
[0067] Meanwhile, in order to perform communication in the
unlicensed band, data is required to be transmitted and received
according to regulations established for each country. More
specifically, according to the above regulations, before a
communication device performs transmission in an unlicensed band,
the communication device "listens" to and identifies whether a
corresponding unlicensed band is occupied by another communication
device, and then if it is determined that the corresponding
unlicensed band is empty, the communication device is required to
perform "transmission". As such, a scheme of listening to a
corresponding band and transmitting a signal when the corresponding
band is empty is referred to as listen-before-talk (LBT). Each
country and unlicensed band has regulations required to carry out
the LBT, and a communication device is required to perform the LBT
when communicating in an unlicensed band according to the
regulations.
[0068] There are two main types of the LBT, such as Type 1 and Type
2.
[0069] FIG. 1D illustrates LBT Type 1 method according to an
embodiment of the disclosure.
[0070] Referring to FIG. 1D, LBT Type 1 corresponds to a method in
which a device randomly determines a time at which the device
determines whether other peripheral devices transmit a signal
through a corresponding unlicensed band before transmitting a
signal, and transmits a signal when a channel is empty during the
corresponding random time. In this case, the device determines
whether a corresponding unlicensed band is used for a fixed time
(T.sub.d), and determines whether a channel is empty (unused) for a
random time (N) when the corresponding unlicensed band is empty
(unused).
[0071] In this case, a method for determining values of the T.sub.d
and N may be changed according to the priority and importance of
traffic and, for example, there may be four determination methods.
The priority of the method for determining the T.sub.d and N values
may be determined according to the priority and importance of the
traffic, which is referred to as a channel access priority class
(CAPC).
[0072] Parameters such as m.sub.p, CW.sub.min,p, and CW.sub.max,p
may be determined according to the CAPC. In order to determine
whether a unlicensed band is occupied, a predetermined time T.sub.d
has a time length of T.sub.d=16+m.sub.p* 9 (.mu.s), an N has a time
length of N=random (0, CW.sub.p) * 9 (.mu.s), and a CW value starts
from CW.sub.min,p, is nearly doubled every time when transmission
fails, and has a maximum value of CW.sub.max,p.
[0073] For example, if the CAPC is 3, the Td has a length of
16+3*9=43 .mu.s. In addition, an N .mu.s may be determined by
multiplying a random value (for example, 7) selected from 0 to 15
by 9 in case of the initial transmission (for example, N is 7*9=63
.mu.s in case where the random value is7. Therefore, according to
the embodiment, the communication device may determine whether a
channel is occupied for 106 .mu.s and transmit a signal when the
channel is empty.
TABLE-US-00001 TABLE 1 Channel Priorty Class (p) m.sub.p
CW.sub.minp CW.sub.maxp T.sub.maxp allowed CW.sub.p sizes 1 1 3 7 2
ms (3, 7) 2 1 7 15 3 ms (7, 15) 3 3 15 63 8 or 10 ms (15, 31, 63) 4
7 15 1023 8 or 10 ms (15, 31, 63, 127, 255, 511, 1023)
[0074] According to the above example (when 7 is selected as a
random value for an N), when it is determined that a channel is
occupied by another device (that is, a received signal strength
(RSSI) is equal to or greater than a predetermined threshold value)
in the middle of determining whether the channel is empty (for
example, when 3 out of 7 passes and 4remains), a UE waits until the
channel occupancy ends, and then waits for T.sub.d again and
determines whether the channel is empty for the remaining time of 4
to perform transmission.
[0075] As can be seen in Table 1, an LBT scheme having a low CAPC
is used when high priority traffic is transmitted.
[0076] FIG. 1E illustrates LBT Type 2 method according to an
embodiment of the disclosure.
[0077] Referring to FIG. 1E, LBT Type 2 corresponds to a method in
which a time at which a device determines whether other peripheral
devices transmit a signal through a corresponding unlicensed band
before transmitting a signal is fixed, and accordingly, the device
immediately transmits a signal when a channel is empty for the
corresponding fixed time.
[0078] That is, in FIG. 1E, the method corresponds to a scheme in
which, when a communication device is required to transmit, if the
device listens to (senses) a channel for a fixed time of
T.sub.short (=T.sub.f+T.sub.s) and determines that the channel is
empty, the device transmits a signal immediately. That is, the
scheme corresponds to an LBT scheme which can be used when a signal
having a very high priority is transmitted.
[0079] FIG. 1F illustrates discontinuous reception (hereinafter,
referred to as DRX) operation of an NR UE according to an
embodiment of the disclosure.
[0080] Referring to FIG. 1F, the DRX corresponds to a method for
monitoring only some PDCCHs according to configuration information
received from an eNB, instead of monitoring all physical downlink
control channels (PDCCHs) to enable a UE to obtain scheduling
information in order to minimize power consumption of the UE.
[0081] A basic DRX operation has a DRX cycle 1f-00 and monitors a
PDCCH only for an OnDuration 1f-05 time. In a connected mode, two
values of a long DRX and a short DRX are configured in the DRX
cycle. In a general case, the long DRX cycle is applied, and if
necessary, the eNB may additionally configure the short DRX cycle.
If both the long DRX cycle and short DRX cycle are configured, the
UE starts a short DRX timer and repeats the same from the short DRX
cycle at the same time. If there is no new traffic until after the
short DRX timer expires, the UE changes from the short DRX cycle to
the long DRX cycle.
[0082] If scheduling information related to a new packet is
received through a PDCCH in operation 1f-10 during the OnDuration
1f-05 time, the UE starts a DRX inactivity timer in operation
1f-15. The UE maintains an active state during the DRX inactivity
timer. That is, the UE continues to monitor the PDCCH. In addition,
the UE also starts a HARQ RTT timer in operation 1f-20. The HARQ
RTT timer is applied to prevent the UE from unnecessarily
monitoring the PDCCH during a HARQ round trip time (RTT), and the
UE is not required to perform PDCCH monitoring during an operation
time of the timer. However, while the DRX inactivity timer and the
HARQ RTT timer are simultaneously operated, the UE continues to
perform PDCCH monitoring with reference to the DRX inactivity
timer. If the HARQ RTT timer expires, a DRX retransmission timer is
started in operation 1f-25. While the DRX retransmission timer is
operated, the UE is required to perform PDCCH monitoring.
[0083] In general, during the DRX retransmission timer operation
time, scheduling information for HARQ retransmission is received in
operation 1f-30. If the scheduling information is received, the UE
immediately stops the DRX retransmission timer and starts the HARQ
RTT timer again. The above operation continues until the packet is
successfully received in operation 1f-35. In addition, if the eNB
has no data anymore to transmit to a corresponding UE while the UE
operates the OnDuration or DRX inactivity timer, the eNB may
transmit a DRX Command MAC CE message. The UE having received the
message stops both the OnDuration timer and the DRX inactivity
timer which are in operation, and the UE uses a short DRX cycle
first when the short DRX is configured, and uses a long DRX cycle
when only the long DRX is configured.
[0084] Meanwhile, when the eNB operates in the unlicensed band as
described in FIGS. 1D and 1E, the eNB is required to perform LBT in
order to transmit scheduling information to the UE. If the eNB
performs LBT and fails to perform the LBT during the
above-mentioned OnDuration even though there is data to be
transmitted, the UE sleeps until the next OnDuration and the eNB is
required to delay the corresponding transmission to the next
OnDuration. As such, if the existing DRX operation is used, a delay
occurs when the LBT fails during the OnDuration. In addition, there
is a problem that the eNB is required to retain data in a very
large buffer to avoid data loss.
[0085] Accordingly, the disclosure proposes a method and device for
solving the above problem.
[0086] FIG. 1G illustrates a first DRX operation used by a UE
operating in an unlicensed band according to an embodiment of the
disclosure.
[0087] Referring to FIG. 1G, graph 1g-01 illustrates that an eNB
operating in an unlicensed band occupies a channel and transmits
data to UEs which have accessed the corresponding eNB. In addition,
graph 1g-03 illustrates a time when UE A monitors a PDCCH, and
graph 1g-05 illustrates a time when UE B monitors a PDCCH.
[0088] Referring to graph 1g-01, if the eNB occupies a channel, the
eNB transmits, to UEs in a cell, occupancy time duration for an
occupancy period 1g-11 and a list of the UEs to be scheduled during
the occupancy time duration by using a broadcast message in
operation 1g-71. Otherwise, the broadcast message may be a unicast
message transmitted to each individual UE. In this case, the
message may include information on whether scheduling is performed
and occupancy time duration.
[0089] The message transmitted by the eNB in operation 1g-71 may be
transmitted through a message of an RRC layer, or may be
transmitted through a MAC control element (CE) which is a MAC layer
control message.
[0090] FIG. 1G illustrates an example in which an instruction
indicating that there is data to be transmitted to the UE A and the
UE B (that is, an indication that both the UE A and the UE B should
be awake) is transmitted through the message of operation 1g-71.
Accordingly, each of the UE A and the UE B may monitor a PDCCH
while waking up during a corresponding occupancy period, based on
occupancy time duration indicated by the eNB, in operations 1g-31
and 1g-51.
[0091] Thereafter, when the corresponding occupancy period ends,
each of the UEs does not monitor the PDCCH for a fixed time or a
value configured by the eNB in operations 1g-33 and 1g-53. This is
because once the eNB has occupied a channel in operation 1g-11, a
predetermined time 1g-13 is required to occupy the channel again (a
predetermined time for occupying the channel again may be
determined by regulations established by each country).
Accordingly, since the eNB cannot occupy the channel during the
corresponding time, the UE is not required to monitor the PDCCH. In
FIG. 1G, the period is referred to as OffDuration in operations
1g-33 and 1g-53.
[0092] After the corresponding OffDuration has passed (or when a
timer corresponding to the OffDuration has expired), the UE starts
PDCCH monitoring in operations 1g-35 and 1g-55. Meanwhile, other
communication devices or other eNBs around the eNB may occupy the
unlicensed band in operation 1g-15. Therefore, if the channel
becomes empty after operation 1g-15, the eNB may occupy the channel
again in operation 1g-17.
[0093] When the eNB occupies the channel again, as in operation
1g-71, the eNB transmits occupancy time duration and a list of UEs
to be scheduled during the occupancy time duration by using a
broadcast or unicast message in operation 1g-73.
[0094] FIG. 1G illustrates a scenario in which only the UE B is
scheduled in an occupancy period 1g-17.
[0095] Therefore, the UE A having received the message 1g-73 is not
required to perform PDCCH monitoring even during a time 1g-17 when
the eNB occupies the channel in operation 1g-37, and is not
required to continuously perform PDCCH monitoring until a period
after the eNB cannot occupy the channel in operation 1g-37.
[0096] In addition, since the UE B has received that the eNB can be
scheduled in the occupancy period, the UE B continuously monitors
the PDCCH during the occupancy period 1g-17 in operation 1g-55.
[0097] Meanwhile, if there is no message indicating whether data
exists, such as 1g-71 and 1g-73, or the UE does not receive the
message, the UE assumes that data exists during the period and
continuously monitors the PDCCH for predetermined time duration
(for example, T.sub.mcot,p described in Table of FIG. 1D).
[0098] Accordingly, the UE can discontinuously perform PDCCH
monitoring, thereby reducing power consumption of the UE.
[0099] FIG. 1H illustrates an operation order of a UE operating in
an unlicensed band when the UE performs a first DRX operation
according to an embodiment of the disclosure.
[0100] Referring to FIG. 1H, in an embodiment of the disclosure, it
is assumed that the UE is already successfully connected to the eNB
and is in an RRC connected state (RRC_CONNECTED) capable of
transmitting and receiving data in operation 1h-01. Thereafter (or
when the UE is switched to the connected state), the UE may receive
DRX-related configuration information from the eNB in operation
1h-03. The configuration information may include the
above-described DRX-related parameter, for example, duration of an
OffDuration timer.
[0101] Thereafter, the UE monitors a PDCCH to receive data from the
eNB, and receives a message related to the existence of data, such
as 1g-71 and 1g-73 above-described in FIG. 1G, in operation 1h-05.
If the message is received, the UE determines whether the eNB
schedules data to the UE in the occupancy period 1g-11 and 1g-17 in
operation 1h-07.
[0102] If the eNB informs the UE to schedule data in the occupancy
period, the UE may start an OnDuration timer according to occupancy
time duration during the occupancy period, and may continuously
monitor a PDCCH during the corresponding period in operation 1h-11.
The UE may receive downlink data according to a result of the PDCCH
monitoring.
[0103] If the OnDuration timer expires, the UE starts an
OffDuration timer as in period 1g-33 of FIG. 1G, and the UE is not
required to monitor the PDCCH during the operation time of the
corresponding timer in operation 1h-13.
[0104] If the eNB informs the UE not to schedule data in the
occupancy period, the UE stops the OnDuration timer when the timer
has been operated, the UE may start the OffDuration timer according
to the time duration of the occupancy period. Accordingly, the UE
is not required to monitor the PDCCH during the corresponding
period in operation 1h-15.
[0105] If the OffDuration timer expires, the UE restarts the
OffDuration timer corresponding the period 1g-37 of FIG. 1G, and
the UE is not required to monitor the PDCCH during the operation
time of the corresponding timer in operation 1h-17.
[0106] Thereafter, if the OffDuration timer expires in operation 1
h-19, the UE monitors the PDCCH and attempts to receive a message
related to the existence of data in operation 1h-05. In this case,
the UE may start the OnDuration timer having a predetermined length
(for example, infinity), or continuously perform PDCCH monitoring
without starting the timer.
[0107] Through above operation, the UE can discontinuously perform
PDCCH monitoring, thereby reducing power consumption of the UE.
[0108] FIG. 1I illustrates a second DRX operation used by a UE
operating in an unlicensed band according to an embodiment of the
disclosure.
[0109] Referring to FIG. 1I, graph 1i-01 illustrates that an eNB
operating in an unlicensed band occupies a channel and transmits
data to UEs which have accessed the corresponding eNB. In addition,
graph 1i-03 illustrates a time when UE A monitors a PDCCH, and
graph 1i-05 illustrates a time when UE B monitors the PDCCH.
[0110] A DRX second operation according to the disclosure proposes
a method in which the UE always monitors a PDCCH, but if the eNB is
unable to occupy a channel as in operations 1i-13 and 1i-17 or the
eNB has no data anymore to transmit to the UE, the UE is not
allowed to perform PDCCH monitoring during an indicated time.
[0111] The eNB informs the UE not to monitor the PDCCH during an
indicated time by using a broadcast message or a unicast message in
operations 1i-71 and 1i-73. The message may be an RRC layer
message, a MAC CE message, or a message transmitted by including an
RNTI specific to a PDCCH.
[0112] Accordingly, the UE operates an OffDuration timer so as not
to monitor the PDCCH during the indicated time after receiving the
message in operations 1i-33 and 1i-53.
[0113] If the OffDuration timer expires, the UE monitors the PDCCH
in operations 1i-35 and 1i-55 until the UE receives the message
from the eNB in operations 1i-75 and 1i-77.
[0114] Accordingly, the UE can discontinuously perform PDCCH
monitoring, thereby reducing power consumption of the UE.
[0115] FIG. 1J illustrates an operation order of a UE operating in
an unlicensed band when the UE performs a second DRX operation
according to an embodiment of the disclosure.
[0116] Referring to FIG. 1J, it is assumed that the UE is already
successfully connected to the eNB and is in an RRC connected state
(RRC CONNECTED) capable of transmitting and receiving data in
operation 1j-01. Thereafter (or when the UE is switched to the
connected state), the UE may receive DRX-related configuration
information from the eNB in operation 1j-03. The configuration
information may include the above-described DRX related parameter,
for example, duration of an OffDuration timer. If a DRX operation
mode is fundamentally supported, the UE may not receive the
configuration information.
[0117] Thereafter, in case where the UE monitors a PDCCH to receive
data from the eNB and receives control information through the
PDCCH, the UE receives or transmits data accordingly in operation
1j-05.
[0118] If the UE receives, from the eNB, a message (e.g., a sleep
command) (1j-07) indicating that PDCCH monitoring is not required
to be performed as in operations 1i-71, 1i-73, 1i-75, and 1i-77 of
FIG. 1I, the UE starts an OffDuration timer corresponding to a time
included in the message and is not required to monitor the PDCCH
during the operation time of the corresponding timer in operation
1j-11.
[0119] Thereafter, if the OffDuration timer expires in operation
1j-13, the UE monitors the PDCCH from the eNB and receives control
information through the PDCCH, and accordingly receives or
transmits data in operation 1j-05.
[0120] Through the operation, the UE can discontinuously perform
PDCCH monitoring, thereby reducing power consumption of the UE.
[0121] FIG. 1K is a block diagram of a UE in a wireless
communication system according to an embodiment of the
disclosure.
[0122] Referring to FIG. 1K, the UE includes a radio frequency (RF)
processor 1k-10, a baseband processor 1k-20, a memory 1k-30, and a
controller 1k-40.
[0123] The RF processor 1k-10 performs a function for transmitting
and receiving a signal through a wireless channel, such as band
conversion and amplification of a signal. That is, the RF processor
1k-10 up-converts a baseband signal provided from the baseband
processor 1k-20 into an RF band signal and then transmits the
converted signal through an antenna, and down-converts an RF band
signal received through the antenna into a baseband signal. For
example, the RF processor 1k-10 may include a transmission filter,
a reception filter, an amplifier, a mixer, an oscillator, a digital
to analog convertor (DAC), and an analog to digital convertor
(ADC). Although only one antenna is illustrated in FIG. 1k, the UE
may include a plurality of antennas. In addition, the RF processor
1k-10 may include a plurality of RF chains. Moreover, the RF
processor 1k-10 may perform beamforming. For the beamforming, the
RF processor 1k-10 may control a phase and a size of each signal
transmitted/received through a plurality of antennas or antenna
elements.
[0124] The baseband processor 1k-20 performs a function for a
conversion between a baseband signal and a bitstream according to a
physical layer standard of a system. For example, when data is
transmitted, the baseband processor 1k-20 generates complex symbols
by encoding and modulating a transmission bitstream. In addition,
when data is received, the baseband processor 1k-20 reconstructs a
received bitstream by demodulating and decoding the baseband signal
provided from the RF processor 1k-10. For example, in an orthogonal
frequency division multiplexing (OFDM) scheme, when data is
transmitted, the baseband processor 1k-20 generates complex symbols
by encoding and modulating a transmission bitstream, maps the
complex symbols to subcarriers, and then configures OFDM symbols
through an inverse fast Fourier transform (IFFT) operation and a
cyclic prefix (CP) insertion. Further, when data is received, the
baseband processor 1k-20 divides the baseband signal provided from
the RF processor 1k-10 in the unit of OFDM symbols, reconstructs
the signals mapped to the subcarriers through a fast Fourier
transform (FFT) operation, and then reconstructs a reception
bitstream through demodulation and decoding.
[0125] The baseband processor 1k-20 and the RF processor 1k-10
transmit and receive a signal as described above. Accordingly, the
baseband processor 1k-20 and the RF processor 1k-10 may be referred
to as a transmitter, a receiver, a transceiver, or a communication
unit. Furthermore, at least one of the baseband processor 1k-20 and
the RF processor 1k-10 may include a plurality of communication
modules to support a plurality of different radio access
technologies. In addition, at least one of the baseband processor
1k-20 and the RF processor 1k-10 may include different
communication modules to process signals of different frequency
bands. For example, the different radio access technologies may
include a wireless LAN (for example, IEEE 802.11) and a cellular
network (for example, LTE). Further, the different frequency bands
may include a super high frequency (SHF) (for example, 2.5 GHz and
5 Ghz) band and a millimeter (mm) wave (for example, 60 GHz)
band.
[0126] The memory 1k-30 stores data such as a basic program, an
application program, and configuration information for an operation
of the UE. In particular, the memory 1k-30 may store information
related to a wireless LAN node performing wireless communication by
using a wireless LAN access technology. The memory 1k-30 provides
data stored according to a request of the controller 1k-40.
[0127] The controller 1k-40 controls overall operations of the UE.
For example, the controller 1k-40 transmits and receives a signal
through the baseband processor 1k-20 and the RF processor 1k-10. In
addition, the controller 1k-40 records data in the memory 1k-30 and
reads the data. To this end, the controller 1k-40 may include at
least one processor. For example, the controller 1k-40 may include
a communication processor (CP) which performs a control for
communication, and an application processor (AP) which controls a
higher layer such as an application program. According to an
embodiment of the disclosure, the controller 1k-40 includes a
multi-connection processor 1k-42 which performs a process for
operating in a multiple connection mode. For example, the
controller 1k-40 may control the UE to perform a procedure of the
operation of the UE illustrated in FIG. 1E.
[0128] The controller 1k-40 according to an embodiment of the
disclosure instructs the UE to determine whether to perform PDCCH
monitoring according to a received configuration and message.
[0129] FIG. 1L illustrates a structure of an eNB according to an
embodiment of the disclosure.
[0130] Referring to FIG. 1L, an eNB may include a transceiver
1l-10, a controller 1l-20, and a memory 1l-30. In the disclosure,
the controller may be defined as a circuit, an application specific
integrated circuit, or at least one processor.
[0131] The transceiver 1l-10 may transmit and receive a signal to
and from other network entities.
[0132] The controller 1l-20 may control overall operations of the
eNB according to an embodiment proposed in the disclosure. For
example, the controller 1l-20 may control a signal flow every
between blocks to perform an operation according to the
above-described flowchart.
[0133] The memory 1l-30 may store at least one piece of information
transmitted and received through the transceiver and information
generated through the controller.
[0134] Methods stated in claims and/or specifications according to
various embodiments may be implemented by hardware, software, or a
combination of hardware and software.
[0135] When the methods are implemented by software, a
computer-readable storage medium for storing one or more programs
(software modules) may be provided. The one or more programs stored
in the computer-readable storage medium may be configured for
execution by one or more processors within the electronic device.
The at least one program may include instructions that cause the
electronic device to perform the methods according to various
embodiments of the disclosure as defined by the appended claims
and/or disclosed herein.
[0136] The programs (software modules or software) may be stored in
non-volatile memories including a random access memory and a flash
memory, a read only memory (ROM), an electrically erasable
programmable read only memory (EEPROM), a magnetic disc storage
device, a compact disc-ROM (CD-ROM), digital versatile discs
(DVDs), or other type optical storage devices, or a magnetic
cassette. Alternatively, any combination of some or all of the may
form a memory in which the program is stored. Further, a plurality
of such memories may be included in the electronic device.
[0137] In addition, the programs may be stored in an attachable
storage device which may access the electronic device through
communication networks such as the Internet, Intranet, local area
network (LAN), wide LAN (WLAN), and storage area network (SAN) or a
combination thereof. Such a storage device may access the
electronic device via an external port. Further, a separate storage
device on the communication network may access a portable
electronic device.
[0138] In the above-described detailed embodiments of the
disclosure, a component included in the disclosure is expressed in
the singular or the plural according to a presented detailed
embodiment. However, the singular or plural expressions are
selected to be suitable for proposed situations for convenience of
description, and the disclosure is not limited to the singular or
plural elements. An element expressed in a plural form may be
configured in singular, or an element expressed in a singular form
may be configured in plural.
[0139] Although the embodiment has been described in the detailed
description of the disclosure, the disclosure may be modified in
various forms without departing from the scope of the disclosure.
Therefore, the scope of the disclosure should not be defined as
being limited to the embodiments, but should be defined by the
appended claims and equivalents thereof.
[0140] Hereinafter, the operating principle of the disclosure will
be described in detail with reference to the accompanying drawings.
In describing the disclosure below, a detailed description of
related known configurations or functions incorporated herein will
be omitted when it is determined that the detailed description
thereof may unnecessarily obscure the subject matter of the
disclosure. The terms which will be described below are terms
defined in consideration of the functions in the disclosure, and
may be different according to users, intentions of the users, or
customs. Therefore, the definitions of the terms should be made
based on the contents throughout the specification.
[0141] In describing the disclosure below, a detailed description
of related known configurations or functions incorporated herein
will be omitted when it is determined that the detailed description
thereof may unnecessarily obscure the subject matter of the
disclosure. Hereinafter, embodiments of the disclosure will be
described with reference to the accompanying drawings.
[0142] The terms used to identify access nodes, the terms referring
to network entities, the terms referring to messages, the terms
referring to interfaces between network entities, and the terms
referring to various pieces of identification information, which
are used in the following description, are exemplified for
convenience of description. Therefore, the disclosure may not be
limited by the terminologies provided below, and other terms that
indicate subjects having equivalent technical meanings may be
used.
[0143] For convenience of description, the disclosure uses terms
and names defined in a 3rd generation partnership project long term
evolution (3GPP LTE) standard. However, the disclosure may not be
limited by the terms and names, and may be equally applied to
systems according to other standards. In the disclosure, an eNB may
be used interchangeably with a gNB for convenience of description.
That is, an eNB described as an eNB may refer to a gNB.
[0144] FIG. 2A illustrates a structure of an LTE system according
to an embodiment of the disclosure.
[0145] Referring to FIG. 2A, as shown, a radio access network of an
LTE system includes an evolved node B, (hereinafter, eNB, Node B,
or base station) 2a-05, 2a-10, 2a-15, and 2a-20 and an MME 2a-25,
and an S-GW 2a-30. A UE 2a-35 accesses an external network through
the eNBs 2a-05 to 2a-20 and the S-GW 2a-30.
[0146] In FIG. 2A, the eNBs 2a-05 to 2a-20 correspond to a
conventional Node B of an UMTS system. The eNBs 2a-05 to 2a-20 are
connected to the UE 2a-35 through a wireless channel, and perform a
more complex function than the conventional Node B. In the LTE
system, all user traffic including real-time services such as voice
over Internet protocol (VoIP) is serviced through a shared channel,
so that there is a need for a device for performing scheduling by
collecting status information of UEs, such as buffer states,
available transmit power states, and channel states. The eNBs 2a-05
to 2a-20 perform this scheduling function.
[0147] A single eNB generally controls a plurality of cells. For
example, in order to implement a transmission rate of 100 Mbps, the
LTE system uses an Orthogonal Frequency Division Multiplexing
(hereinafter, referred to as OFDM) as a wireless access technology
in a bandwidth of 20 MHz. Further, an adaptive modulation and
coding (hereinafter, referred to as AMC) scheme of determining a
modulation scheme and a channel coding rate is applied to the LTE
system in correspondence to UE channel states.
[0148] The S-GW 2a-30 corresponds to a device for providing a data
bearer, and generates or removes the data bearer under a control of
the MME 2a-25.
[0149] The MME corresponds to a device which is in charge of
various control functions including a mobility management function
for a UE, and is connected to a plurality of eNBs.
[0150] FIG. 2B illustrates a wireless protocol structure in an LTE
system according to an embodiment of the disclosure.
[0151] Referring to FIG. 2B, in relation to a wireless protocol
structure of an LTE system, each of a UE and an eNB includes a PDCP
layer 2b-05 or 2b-40, an RLC layer 2b-10 or 2b-35, and a MAC layer
2b-15 or 2b-30.
[0152] The PDCP layer 2b-05 or 2b-40 is responsible for IP header
compression/decompression. The main functions of the PDCP layer are
summarized as follows: [0153] Header compression and decompression
function (header compression and decompression: ROHC only) [0154]
User data transmission function (transfer of user data) [0155]
Sequential delivery function (in-sequence delivery of upper layer
PDUs at PDCP re-establishment procedure for RLC AM) [0156]
Reordering function (For split bearers in DC (only support for RLC
AM): PDCP PDU routing for transmission and PDCP PDU reordering for
reception) [0157] Duplicate detection function (duplicate detection
of lower layer SDUs at PDCP re-establishment procedure for RLC AM)
[0158] Retransmission function (retransmission of PDCP SDUs at
handover and, for split bearers in DC, of PDCP PDUs at PDCP
data-recovery procedure, for RLC AM) [0159] Ciphering and
deciphering function (ciphering and deciphering) [0160] Timer-based
SDU deletion function (timer-based SDU discard in uplink.)
[0161] The radio link control (RLC) layer 2b-10 or 2b-35
reconfigures PDCP packet data units (PDCP PDUs) to a proper size to
perform an ARQ operation. The main functions of the RLC layer are
summarized as follows: [0162] Data transmission function (transfer
of upper layer PDUs) [0163] ARQ function (error correction through
ARQ (only for AM data transfer)) [0164] Concatenation,
segmentation, and reassembly function (concatenation, segmentation
and reassembly of RLC SDUs (only for UM and AM data transfer))
[0165] Re-segmentation function (re-segmentation of RLC data PDUs
(only for AM data transfer)) [0166] Reordering function (reordering
of RLC data PDUs (only for UM and AM data transfer) [0167]
Duplicate detection function (duplicate detection (only for UM and
AM data transfer)) [0168] Error detection function (protocol error
detection (only for AM data transfer)) [0169] RLC SDU deletion
function (RLC SDU discard (only for UM and AM data transfer))
[0170] RLC re-establishment function (RLC re-establishment)
[0171] The MAC 2b-15 or 2b-30 is connected to several RLC-layer
devices configured in one UE, and performs an operation of
multiplexing RLC PDUs to a MAC PDU and demultiplexing RLC PDUs from
a MAC PDU. The main functions of the MAC are summarized as follow:
[0172] Mapping function (mapping between logical channels and
transport channels) [0173] Multiplexing and demultiplexing function
(multiplexing/demultiplexing of MAC SDUs belonging to one or
different logical channels into/from transport blocks (TB)
delivered to/from the physical layer on transport channels) [0174]
Scheduling information report function (scheduling information
reporting) [0175] HARQ function (error correction through HARQ)
[0176] Logical channel priority control function (priority handling
between logical channels of one UE) [0177] UE priority control
function (priority handling between UEs by means of dynamic
scheduling) [0178] MBMS service identification function (MBMS
service identification) [0179] Transmission format selection
function (transport format selection) [0180] Padding function
(padding)
[0181] Physical layers 2b-20 and 2b-25 channel-code and modulate
higher layer data into OFDM symbols and transmit the OFDM symbols
through a wireless channel, or demodulate and channel-decode OFDM
symbols received through the wireless channel to transfer the OFDM
symbols to a higher layer.
[0182] FIG. 2C illustrates a structure of a next-generation mobile
communication system according to an embodiment of the
disclosure.
[0183] Referring to FIG. 2C, a radio access network of a
next-generation mobile communication system (hereinafter, NR or 5G)
includes a new radio node B (hereinafter, referred to as an NR gNB,
gNB, or base station) 2c-10 and a new radio core network (NR CN)
2c-05. A user terminal (hereinafter, referred to as a new radio
user equipment (NR UE) or a UE) 2a-15 accesses an external network
through the NR gNB 2a-10 and the NR CN 2a-05.
[0184] In FIG. 2C, the NR gNB 2c-10 corresponds to an evolved Node
B (eNB) of a conventional LTE system. The NR gNB may be connected
to an NR UE 2c-15 through a radio channel and may provide better
service than a conventional node B. Since all user traffic is
served through a shared channel in the next-generation mobile
communication system, a device for collecting and scheduling status
information of buffer statuses, available transmission power
statuses, and channel statuses of UEs is required, which
corresponds to the NR gNB 2c-10.
[0185] One NR gNB generally controls a plurality of cells. The NR
gNB may have a bandwidth equal to or wider than the conventional
maximum bandwidth in order to implement super-high-speed data
transmission compared to current LTE and may apply orthogonal
frequency division multiplexing (OFDM) through radio access
technology and further apply beamforming technology. Further, a
modulation scheme and an adaptive modulation and coding (AMC)
scheme of determining a channel coding rate are applied in
accordance with a channel status of the UE.
[0186] The NR CN 2c-05 performs a function of supporting mobility,
configuring a bearer, and configuring a QoS. The NR CN is a device
for performing a function of managing the mobility of the UE and
various control functions, and is connected to a plurality of gNBs.
Further, the next-generation mobile communication system may be
linked to the conventional LTE system, and the NR CN is connected
to an MME 2c-25 through a network interface. The MME is connected
to an eNB 2c-30, which is a conventional base station.
[0187] FIG. 2D illustrates a wireless protocol structure of a
next-generation mobile communication system according to an
embodiment of the disclosure.
[0188] FIG. 2D further illustrates a wireless protocol structure of
a next-generation mobile communication system to which the
disclosure can be applied.
[0189] Referring to FIG. 2D, the wireless protocol of the
next-generation mobile communication system includes NR SDAPs 2d-01
and 2d-45, NR PDCPs 2d-05 and 2d-40, NR RLCs 2d-10 and 2d-35, and
NR MACs 2d-15 and 2d-30 in the UE and the NR gNB.
[0190] Main functions of the NR SDAPs 2d-01 and 2d-45 may include
some of the following functions. [0191] User data transmission
function (transfer of user data) [0192] Function of mapping QoS
flow and a data bearer for uplink and downlink (mapping between a
QoS flow and a DRB for both DL and UL) [0193] Function of making a
QoS flow ID for uplink and downlink (marking QoS flow ID in both DL
and UL packets) [0194] Function of mapping reflective QoS flow to a
data bearer for uplink SDAP PDUs (reflective QoS flow to DRB
mapping for the UL SDAP PDUs)
[0195] With respect to the SDAP layer device, the UE may receive a
configuration of whether to use a header of the SDAP layer device
or a function of the SDAP layer device for each PDCP layer device,
each bearer, or each logical channel through an RRC message. If the
SDAP header is configured, a 1-bit indicator of NAS reflective QoS
and a 1 bit-indicator of AS reflective QoS may indicate that the UE
updates or reconfigures information on mapping of QoS flow and a
data bearer in uplink and downlink. The SDAP header may include QoS
flow ID information indicating the QoS. The QoS information may be
used as data processing priority and scheduling information for
seamlessly supporting a service.
[0196] The main functions of the NR PDCPs 2d-05 and 2d-40 may
include some of the following functions. [0197] Header compression
and decompression function (header compression and decompression:
ROHC only) [0198] User data transmission function (transfer of user
data) [0199] Sequential delivery function (in-sequence delivery of
upper layer PDUs) [0200] Non-sequential delivery function
(out-of-sequence delivery of upper layer PDUs) [0201] Reordering
function (PDCP PDU reordering for reception) [0202] Duplicate
detection function (duplicate detection of lower layer SDUs) [0203]
Retransmission function (retransmission of PDCP SDUs) [0204]
Ciphering and deciphering function (ciphering and deciphering)
[0205] Timer-based SDU deletion function (timer-based SDU discard
in uplink)
[0206] The reordering function of the NR PDCP device is a function
of sequentially reordering PDCP PDUs received by a lower layer on
the basis of a PDCP Sequence Number (SN), and may include a
function of sequentially transferring the reordered data to a
higher layer, a function of directly transmitting the recorded
data, a function of recording PDCP PDUs lost due to the reordering,
a function of reporting statuses of the lost PDCP PDUs to a
transmitting side, and a function of making a request for
retransmitting the lost PDCP PDUs.
[0207] The main functions of the NR RLC 2d-10 or 2d-35 may include
some of the following functions. [0208] Data transmission function
(transfer of upper layer PDUs) [0209] Sequential delivery function
(in-sequence delivery of upper layer PDUs) [0210] Non-sequential
delivery function (out-of-sequence delivery of upper layer PDUs)
[0211] ARQ function (Error correction through ARQ) [0212]
Concatenation, segmentation, and reassembly function
(Concatenation, segmentation and reassembly of RLC SDUs) [0213]
Re-segmentation function (re-segmentation of RLC data PDUs) [0214]
Reordering function (reordering of RLC data PDUs) [0215] Duplicate
detection function (duplicate detection) [0216] Error detection
function (protocol error detection) [0217] RLC SDU deletion
function (RLC SDU discard) [0218] RLC re-establishment function
(RLC re-establishment)
[0219] The sequential delivery function (In-sequence delivery) of
the NR RLC device is a function of sequentially transferring PDCP
PDUs received from a lower layer to a higher layer, and may
include, when one original RLC SDU is divided into a plurality of
RLC SDUs and then received, a function of reassembling and
transmitting the RLC SDUs, a function of reordering the received
RLC PDUs on the basis of an RLC Sequence Number (SN) or a PDCP SN,
a function of recording PDCP PDUs lost due to the reordering, a
function of reporting statuses of the lost PDCP PDUs to a
transmitting side, a function of making a request for
retransmitting the lost PDCP PDUs, if there is a lost RLC SDU, a
function of sequentially transferring only RLC SDUs preceding the
lost RLC SDU to the higher layer, if a predetermined timer expires
even though there is a lost RLC SDU, a function of sequentially
transferring all RLC SDUs received before the timer starts to the
higher layer, or if a predetermined timer expires even though there
is a lost RLC SDU, a function of sequentially transferring all RLC
SDUs received up to that point in time to the higher layer.
Further, the NR RLC device may process the RLC PDUs sequentially in
a reception order thereof (according to an arrival order regardless
of a serial number or a sequence number) and may transfer the RLC
PDUs to the PDCP device regardless of the sequence thereof
(out-of-sequence delivery). In the case of segments, the NR RLC
device may receive segments which are stored in the buffer or will
be received in the future, reconfigure the segments to be one RLC
PDU, process the RLC PDU, and then transmit the same to the PDCP
device. The NR RLC layer may not include a concatenation function,
and the function may be performed by the NR MAC layer, or may be
replaced with a multiplexing function of the NR MAC layer.
[0220] The non-sequential function (Out-of-sequence delivery) of
the NR RLC device is a function of transferring RLC SDUs received
from a lower layer directly to a higher layer regardless of the
sequence of the RLC SDUs, and may include, when one original RLC
SDU is divided into a plurality of RLC SDUs and then received, a
function of reassembling and transmitting the RLC PDUs and a
function of storing RLC SNs or PDCP SNs of the received RLC PDUs,
reordering the RLC PDUs, and recording lost RLC PDUs.
[0221] The NR MACs 2d-15 and 2d-30 may be connected to a plurality
of NR RLC layer devices configured in one UE, and the main
functions of the NR MACs may include some of the following
functions. [0222] Mapping function (mapping between logical
channels and transport channels) [0223] Multiplexing and
demultiplexing function (multiplexing/demultiplexing of MAC SDUs)
[0224] Scheduling information report function (scheduling
information reporting) [0225] HARQ function (error correction
through HARQ) [0226] Logical channel priority control function
(priority handling between logical channels of one UE) [0227] UE
priority control function (priority handling between UEs by means
of dynamic scheduling) [0228] MBMS service identification function
(MBMS service identification) [0229] Transport format selection
function (transport format selection) [0230] Padding function
(padding)
[0231] The PHY layers 2d-20 and 2d-25 perform an operation for
channel-coding and modulating higher-layer data to generate an OFDM
symbol and transmitting the OFDM symbol through a radio channel or
demodulating and channel-decoding the OFDM symbol received through
the radio channel and transmitting the demodulated and
channel-decoded OFDM symbol to the higher layer.
[0232] FIG. 2E illustrates a procedure in which the gNB releases
the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-idle mode and a procedure in which the
UE configures the connection with the gNB and thus switches from
the RRC-idle mode to the RRC-connected mode according to an
embodiment of the disclosure.
[0233] Referring to FIG. 2E, according to an embodiment of the
disclosure, if the UE, which transmits and receives data in the
RRC-connected mode, has no data transmission and reception for a
predetermined purpose or for a predetermined time, the gNB may
transmit an RRC connection release message (RRCRelease message) to
the UE and thus the UE may switch to the RRC-idle mode in operation
2e-01.
[0234] If the UE, which currently has no connection (hereinafter,
referred to as an idle-mode UE), has data to be transmitted in the
future, the UE may perform an RRC connection establishment process
with the gNB.
[0235] The UE establishes backward transmission synchronization
with the gNB through a random access process and transmits an RRC
connection request message (RRCSetupRequest message) to the gNB in
operation 2e-05. The RRC connection request message may include an
ID of the UE and at least one piece of information on the reason
why the UE desires to establish the connection.
[0236] The gNB transmits an RRC connection setup message (RRCSetup
message) to configure the RRC connection in operation 2e-10. The
RRC connection setup message may include RRC connection setup
information.
[0237] The RRC connection is also referred to as a signaling radio
bearer (SRB), and is used for transmitting and receiving an RRC
message which is a control message between the UE and the gNB. The
UE configuring the RRC connection transmits an RRC connection setup
completion message (RRCSetupComplete message) to the gNB in
operation 2e-15. The RRC connection setup completion message may
include a service request message which the UE transmits to an AMF
to configure a bearer for a predetermined service.
[0238] The gNB may transmit an initial UE message including the
service request message included in the RRC connection setup
completion message to the AMF in operation 2e-20, and the AMF may
determine whether to provide the service requested by the UE.
[0239] If it is determined to provide the service requested by the
UE on the basis of the determination result, the AMF transmits an
initial UE context setup request message to the gNB in operation
2e-25. The initial UE context setup request message may include at
least one piece of quality of service (QoS) information to be
applied when a data radio bearer (DRB) is configured and
security-related information to be applied to the DRB (for example,
a security key and a security algorithm).
[0240] The gNB may transmit a security mode command message
(SecurityModeCommand message) to the UE in order to set security in
operation 2e-30 and receive a security mode completion message
(SecurityModeComplete message) in operation 2e-35.
[0241] If the security is completely set, the gNB transmits an RRC
connection reconfiguration message (RRCReconfiguration message) to
the UE in operation 2e-40. The RRC connection reconfiguration
message includes configuration information of a DRB to process user
data, and the UE applies the information to configure the DRB and
transmits an RRC connection reconfiguration completion message
(RRCReconfigurationComplete message) to the gNB in operation
2e-45.
[0242] The gNB having completely configured the DRB with the UE
transmits an initial UE context setup request response message
(initial UE context setup response message) to the AMF in operation
2e-50, and the AMF receiving the message establishes a PDU session
through a session management procedure with a UPF in operation
2e-55. If the above process is completed, the UE transmits and
receives data to and from the gNB through the UPF in operations
2e-60 and 2e-65. As described above, the general data transmission
process largely consists of three operations such as RRC connection
setup, security setup, and DRB setup. Further, the gNB may transmit
an RRCReconfiguration message in order to provide a new
configuration to the UE or add or change the configuration for a
predetermined reason in operation 2e-70.
[0243] As described above, the UE needs many signaling procedures
to configure the RRC connection and switch from the RRC-idle mode
to the RRC-connected mode. Accordingly, the next-generation mobile
communication system may newly define the RRC-inactive mode, and
the UE and the gNB may store UE context in such a new mode and
maintain an S1 bearer if necessary, and thus if the RRC-inactive
mode UE accesses the network again, the UE may more rapidly access
the network through a smaller signaling procedure due to an RRC
reconnection configuration procedure described below and transmit
and receive data.
[0244] FIG. 2F illustrates a procedure in which the gNB releases
the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the gNB and thus switches
from the RRC-inactive mode to the RRC-connected mode according to
an embodiment of the disclosure.
[0245] Referring to FIG. 2F, a UE 2f-01 may make a network
connection with a gNB 2f-02 and transmit and receive data. If the
gNB should transition the UE to an RRC-inactive mode for a
predetermined reason, the gNB may transmit an RRC connection
release message (RRCRelease message) including suspend
configuration information (suspendConfig) in operation 2f-05 so as
to transition the UE to the RRC-inactive mode.
[0246] UE operation proposed when the UE receives the RRCRelease
message including the suspend configuration information in
operation 2f-05 is described below. The UE may perform some or all
of the following operations or may skip some operations.
[0247] If the RRCRelease message includes suspend configuration
information (suspendConfig), the UE may apply the received suspend
configuration information.
[0248] If there is no RAN notification area information
(RAN-NotificationAreaInfo) in the suspend configuration
information, the UE may apply a RAN notification area information
that the UE stores in advance. This is to support a delta
configuration for the UE because the size of the RAN notification
area information is big.
[0249] If there is RAN notification area information in the suspend
configuration information, the UE may update the stored values to
be new RAN notification area information included in the suspend
configuration information of the RRCRelease message.
[0250] If there is no timer value (for example, t380) in the
suspend configuration information, the UE may release t380 that has
been already stored.
[0251] If there is t380 in the suspend configuration information,
the UE may store t380 included in the suspend configuration
information of the RRCRelease message.
[0252] The UE may store at least one piece of information such as a
full UE connection resume identifier (Full-RNTI), a partitioned UE
connection resume identifier (ShortI-RNTI), NCC
(nextHopChainingCount), and a RAN paging cycle (RAN-PagingCycle)
included in the suspend configuration information.
[0253] Further, the UE may reset the MAC layer device. This is to
prevent unnecessary retransmission when the connection of data
stored in the HARQ buffer resumes.
[0254] The UE may re-establish the RLC layer devices for all SRBs
and DRBs. This is to prevent unnecessary retransmission when the
connection of data stored in the RLC buffer resumes and to
initialize parameters to be used in the future.
[0255] Unless the UE receives the RRCRelease message including the
suspend configuration information in response to an RRC connection
resume request message (RRCResumeRequest message), the UE may store
UE context. The UE context may include at least one of current RRC
configuration information, current security context information,
PDCP status information including ROHC status information, SDAP
configuration information, a UE cell identifier (C-RNTI) used in a
source cell (source PCell), a cell identity of a source cell
(CellIdentity), and a physical cell identity.
[0256] The UE may suspend all SRBs and DRBs except for SRB0.
[0257] The UE may start the timer t380 with a period LAN
notification area update timer value (PeriodicRNAU-TimerValue)
included in the suspend configuration information.
[0258] The UE may report suspension of the RRC connection to a
higher layer.
[0259] The UE configures lower layer devices to stop an integrity
protection and encryption function.
[0260] Further, the UE may transition to the RRC-inactive mode.
[0261] As described above, the UE transitioning to the RRC-inactive
mode in operation 2f-10 may reselect or switch/transition from a
current equivalent public land mobile network (PLMN) or a
registered PLMN to another equivalent PLMN during movement I
operation 2f-15. If the UE reselects or transitions to another
equivalent PLMN, the proposed UE operation is as described
below.
[0262] If the gNB supports sharing of networks (sharing of a
plurality of equivalent PLMNs), higher layer devices (upper layers)
or the NAS layer of the UE may inform the RRC layer or the AS layer
(or lower layer) of the UE of reselection of or switching to
another equivalent PLMN. In addition, the higher layer devices or
the NAS layer of the UE may inform the RRC layer or the AS layer of
the UE of the reason of connection resume through mo-signaling. The
RRC layer or the AS layer of the UE may store the selected
PLMN-identify provided by the higher layers or the NAS layer of the
UE. For example, the UE may store the selected PLMN-identity in an
internal state variable. In addition, the RRC layer or the AS layer
of the UE may store mo-signaling.
[0263] If the RRC-inactive UE is located in a RAN-based
notification area (RNA) that is not included in LAN notification
area information configured in the UE after the timer t380 expires
or after a cell reselection process in the above-described
procedure, a RAN-based notification area update (RNAU) procedure
may be triggered in operation 2f-20.
[0264] If the higher layer or the RRC layer of the UE makes a
request for resuming the RRC connection, the RRC-inactive mode UE
may perform a random access procedure and transmit an RRC message
to the gNB in operation 2f-25, and the UE operation proposed
therefor is described below.
[0265] Specifically, the UE may perform at least one of the
following operations in connection with transmission of an
RRCResume Request message or an RRCResumeRequest1 message.
Alternatively, the following operations may be omitted.
[0266] If a useFullResumeID field is signaled through system
information (SIB1), the UE may select RRCResumeRequest1 as a
message to be transmitted to the gNB. The UE may configure
resumeIdentity as a full UE connection resume identifier value
(fullI-RNTI value). The fullI-RNTI value may be stored in the UE.
The UE may transmit the RRCResumeRequest1 message including the
resumeIdentity.
[0267] Otherwise, the UE may select an RRCResumeRequest as a
message to be transmitted to the gNB. The UE may configure
shortResumeIdentity as a partitioned UE connection resume
identifier value (shortI-RNTI value). The UE may transmit an
RRCResumeRequest message including shortResumeIdentity.
[0268] The UE may select mo-Signaling as a reason to resume the
connection (resumeCause).
[0269] If higher layer devices or the NAS layer of the UE provide a
PLMN, the PLMN selected by the higher layer device or the NAS layer
of the UE may be configured as selectedPLMN-Identity on the basis
of a PLMN-IdentityList included in SIB1. Accordingly, the UE may
transmit an RRCResumeRequest message or an RRCResumeRequest1
message including the selectedPLMN-Identity. In the disclosure, the
RRCResumeRequest message may also be referred to as a first
RRCResumeRequest message, and the RRCResumeRequest1 message may
also be referred to as a second RRCResumeRequest message.
[0270] The UE may calculate MAC-I and insert the MAC-I into the
selected message.
[0271] The UE may reconstruct RRC configuration information and
security context information on the basis of UE context except for
cell group configuration information (cellGroupConfig). The UE
context may be stored in the UE.
[0272] The UE updates a new KgNB security key on the basis of a
current KgNB security key, an NH (NextHop) value, and an NCC value.
The NCC value may be stored in the UE.
[0273] The UE may induce new security keys (K_RRCenc, K_RRC_int,
K_UPint, and K_UPenc) to be used in an integrity protection and
verification procedure and an encryption and decryption procedure
using the newly updated KgNB security key.
[0274] The UE may resume the integrity protection and verification
procedure by applying the updated security keys and a previously
configured algorithm to all bearers except for SRB0 and then apply
integrity verification and protection to transmitted and received
data. This is to increase reliability and security of data
transmitted and received from SRB1 or DRBs.
[0275] The UE may resume an encryption and decryption procedure by
applying the updated security keys and a previously configured
algorithm to all bearers except for SRB0 and then apply encryption
and decryption to transmitted and received data. This is to
increase reliability and security of data transmitted and received
from SRB1 or DRBs.
[0276] The UE may reconstruct a PDCP status and reestablish PDCP
entities for SRB1.
[0277] Further, the UE resumes SRB1. This is because an RRCResume
message is received through SRB1 in response to an RRCResumeRequest
message or an RRCResumeRequest1 message to be transmitted.
[0278] Thereafter, the higher layer of the UE may transmit the
selected message to be transmitted to the gNB, that is, the
RRCResumeRequest message or the RRCResumeRequest1 message to lower
layer devices.
[0279] Accordingly, the UE may transmit the RRCResumeRequest
message or the RRCResumeRequest1 message to the gNB. Further, the
UE may transmit the RRCResumeRequest message or the
RRCResumeRequest1 message and start a timer T319.
[0280] If the RNAU procedure is triggered, the UE may perform a
random access procedure to perform the RNAU procedure and transmit
the RRCResumeRequest message or the RRCResumeRequest1 message to
the gNB in operation 2f-25, and may receive an RRC connection
resume message (RRCResume message) in response thereto in operation
2f-30. The UE operation proposed in such a case is described below
in operation 2f-30. The UE may perform at least one of the
following operations or the following operations may be
omitted.
[0281] If the UE receives the RRCResume message, the UE stops the
driven timer T319 according to transmission of the RRCResumeRequest
message or the RRCResumeRequest1 message.
[0282] If full configuration information (fullConfig) is included
in the RRCResume message, the UE performs a full configuration
procedure. Otherwise, if the UE receives the RRCResume message, the
UE may reconstruct the PDCP status and reset a COUNT value for SRB2
and all DRBs. The UE may reconstruct cell group configuration
information (cellGroupConfig) on the basis of stored UE context.
The UE indicates this to lower layer devices.
[0283] The UE may release the full UE connection resume identifier
(FullI-RNTI), the partitioned UE connection resume identifier
(ShortI-RNTI), and the stored UE context. At this time, the UE does
not release RAN notification area information
(RAN-NotificationAreaInfo).
[0284] If master cell group (masterCellgroup) configuration
information is included in the RRCResume message, the UE may
perform a cell group configuration procedure according to
configuration information.
[0285] If bearer configuration information (radioBearerConfig) is
included in the RRCResume message, the UE may configure a bearer
according to configuration information.
[0286] The UE may resume SRB2 and all DRBs.
[0287] If the UE stores cell reselection priority information, the
UE may discard the information. The information may be cell
reselection priority information, stored on the basis of
CellReselectionPriorities that may be included in the RRCRelease
message or received from another RAT.
[0288] If the timer T320 is being driven, the UE may stop it.
[0289] If frequency measurement configuration information
(measConfig) is included in the RRCResume message, the UE may
measure a frequency according to configuration information.
[0290] If the RRC connection is suspended, the UE may resume
frequency measurement.
[0291] The UE transitions to the RRC-connected mode in operation
2f-35. Accordingly, the UE indicates to higher layer devices that
the RRC connection, which had been suspended, is resumed. The UE
may stop the cell reselection procedure. The UE may consider a
currently accessed cell as a primary cell (PCell).
[0292] The UE transitioning to the RRC-connected mode may transmit
an RRC connection resume completion message (RRCResumeComplete
message) in operation 2f-40. Specifically, the UE may configure the
RRCResumeComplete message as follows.
[0293] If higher layer devices provide a NAS PDU, the UE may insert
the NAS PDU into a dedicatedNAS-Message.
[0294] If higher layer devices or the NAS layer provide a PLMN, the
PLMN selected by the higher layer devices or the NAS layer may be
configured as a selectedPLMN-Identity on the basis of a
PLMN-IdentityList included in SIB1.
[0295] The gNB receiving the RRCResumeComplete message may transmit
an RRCRelease message including suspend configuration information
to the UE in operation 2f-45. Alternatively, if the gNB does not
transmit the RRCRelease message including the suspend configuration
information to the UE in operation 2f-45, the UE may transmit and
receive data to and from the gNB. Alternatively, the gNB may
transmit another RRC message (for example, an RRCReject message or
an RRCRelease message including no suspend configuration
information) to the UE in operation 2f-45.
[0296] FIG. 2G illustrates a procedure in which the gNB releases
the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the gNB and thus switches
from the RRC-inactive mode to the RRC-connected mode according to
an embodiment of the disclosure.
[0297] Referring to FIG. 2G, a UE 2g-01 may make a network
connection with a gNB 2g-02 and transmit and receive data. If the
gNB should transition the UE to an RRC-inactive mode for a
predetermined reason, the gNB may transmit an RRC connection
release message (RRCRelease message) including suspend
configuration information (suspendConfig) in operation 2g-05 so as
to transition the UE to the RRC-inactive mode.
[0298] The UE operation proposed when the UE receives the
RRCRelease message including the suspend configuration information
in operation 2f-05 is described below. The UE may perform some or
all of the following operations or may skip some operations.
[0299] If the RRCRelease message includes suspend configuration
information (suspendConfig), the UE may apply the received suspend
configuration information.
[0300] If there is no RAN notification area information
(RAN-NotificationAreaInfo) in the suspend configuration
information, the UE may apply a RAN notification area information
that the UE stores in advance. This is to support a delta
configuration for the UE because the size of the RAN notification
area information is big.
[0301] If there is RAN notification area information in the suspend
configuration information, the UE may update the stored values to
be new RAN notification area information included in the suspend
configuration information of the RRCRelease message.
[0302] If there is no timer value (for example, t380) in the
suspend configuration information, the UE may release t380 that has
been already stored.
[0303] If there is t380 in the suspend configuration information,
the UE may store t380 included in the suspend configuration
information of the RRCRelease message.
[0304] The UE may store at least one piece of information such as a
full UE connection resume identifier (Full-RNTI), a partitioned UE
connection resume identifier (ShortI-RNTI), NCC
(nextHopChainingCount), and a RAN paging cycle (RAN-PagingCycle)
included in the suspend configuration information.
[0305] Further, the UE may reset the MAC layer device. This is to
prevent unnecessary retransmission when the connection of data
stored in the HARQ buffer resumes.
[0306] The UE may re-establish the RLC layer devices for all SRBs
and DRBs. This is to prevent unnecessary retransmission when the
connection of data stored in the RLC buffer resumes and initializes
parameters to be used in the future.
[0307] Unless the UE receives the RRCRelease message including the
suspend configuration information in response to an RRC connection
resume request message (RRCResumeRequest message), the UE may store
UE context. The UE context may include at least one of current RRC
configuration information, current security context information,
PDCP status information including ROHC status information, SDAP
configuration information, a UE cell identifier (C-RNTI) used in a
source cell (source PCell), a cell identity of a source cell
(CellIdentity), and a physical cell identity.
[0308] The UE may suspend all SRBs and DRBs except for SRB0.
[0309] The UE may start the timer t380 with a period LAN
notification area update timer value included in the suspend
configuration information.
[0310] The UE may report suspension of the RRC connection to a
higher layer.
[0311] The UE configures lower layer devices to stop an integrity
protection and encryption function.
[0312] Further, the UE may transition to the RRC-inactive mode.
[0313] As described above, the UE transitioning to the RRC-inactive
mode in operation 2g-10 may reselect or switch/transition from a
current equivalent PLMN or a registered PLMN to another equivalent
PLMN during movement in operation 2g-15.
[0314] If the RRC-inactive UE is located in a RAN-based
notification area (RNA) that is not included in LAN notification
area information configured in the UE after the timer t380 expires
or after a cell reselection process, a RAN-based notification area
update (RNAU) procedure may be triggered in operation 2g-20.
[0315] Accordingly, a lower layer of the UE may inform the NAS
layer or higher layer devices of the UE that the RAN-based
notification area update procedure is performed in operation 2g-25.
At this time, if the NAS layer or higher layer devices reselect or
transition to another equivalent PLMN, the UE may generate a NAS
PDU and transmit the NAS PDU to the AS layer device.
[0316] The RRC-inactive mode UE may perform a random access
procedure and transmit an RRC message to the gNB, and the UE
operation proposed therefor is described below in operation 2g-30.
The UE may perform at least one of the following operations in
connection with transmission of an RRCResume Request message or an
RRCResumeRequest1 message. Alternatively, the following operation
may be omitted.
[0317] If a useFullResumeID field is signaled through system
information (SIB1), the UE may select RRCResumeRequest1 as a
message to be transmitted to the gNB. The UE may configure
resumeIdentity as a full UE connection resume identifier value
(fullI-RNTI value). The fullI-RNTI value may be stored in the UE.
The UE may transmit the RRCResumeRequest1 message including the
resumeIdentity.
[0318] Otherwise, the UE may select an RRCResumeRequest as a
message to be transmitted to the gNB. The UE may configure
shortResumeIdentity as a partitioned UE connection resume
identifier value (shortI-RNTI value). The shortI-RNTI value may be
stored in the UE. The UE may transmit an RRCResumeRequest message
including shortResumeIdentity.
[0319] The UE may select mo-Signalling as a reason to resume the
connection (resumeCause).
[0320] If higher layer devices or the NAS layer of the UE provide a
PLMN, the PLMN selected by the higher layer device or the NAS layer
of the UE may be configured as selectedPLMN-Identity on the basis
of a PLMN-IdentityList included in SIB1. Accordingly, the UE may
transmit an RRCResumeRequest message or an RRCResumeRequest 1
message including the selectedPLMN-Identity.
[0321] The UE may calculate MAC-I and insert the MAC-I into the
selected message.
[0322] The UE may reconstruct RRC configuration information and
security context information on the basis of UE context except for
cell group configuration information (cellGroupConfig). The UE
context may be stored in the UE.
[0323] The UE updates a new KgNB security key on the basis of a
current KgNB security key, an NH (NextHop) value, and an NCC value.
The NCC value may be stored in the UE.
[0324] The UE may induce new security keys (K_RRCenc, K_RRC_int,
K_UPint, and K_UPenc) to be used in an integrity protection and
verification procedure and an encryption and decryption procedure
using the newly updated KgNB security key.
[0325] The UE may resume the integrity protection and verification
procedure by applying the updated security keys and a previously
configured algorithm to all bearers except for SRB0 and then apply
integrity verification and protection to transmitted and received
data. This is to increase reliability and security of data
transmitted and received from SRB1 or DRBs.
[0326] The UE may resume an encryption and decryption procedure by
applying the updated security keys and a previously configured
algorithm to all bearers except for SRB0 and then apply encryption
and decryption to transmitted and received data. This is to
increase reliability and security of data transmitted and received
from SRB1 or DRBs.
[0327] The UE may reconstruct a PDCP status and reestablish PDCP
entities for SRB1.
[0328] Further, the UE resumes SRB1. This is because an RRCResume
message is received through SRB1 in response to an RRCResumeRequest
message or an RRCResumeRequest1 message to be transmitted.
[0329] Thereafter, the higher layer of the UE may transmit the
selected message to be transmitted to the gNB, that is, the
RRCResumeRequest message or the RRCResumeRequest message to lower
layer devices.
[0330] Accordingly, the UE may transmit the RRCResumeRequest
message or the RRCResumeRequest message to the gNB. Further, the UE
may transmit the RRCResumeRequest message or the RRCResumeRequest
message and start a timer T319.
[0331] If the RNAU procedure is triggered, the UE may perform a
random access procedure to perform the RNAU procedure and transmit
the RRCResumeRequest message or the RRCResumeRequest1 message to
the gNB in operation 2g-30, and may receive an RRC connection
resume message (RRCResume message) in response thereto in operation
2g-35. The UE operation proposed in such a case is described below
in operation 2g-35. The UE may perform at least one of the
following operations or the following operations may be
omitted.
[0332] If the UE receives the RRCResume message, the driven timer
T319 stops according to transmission of the RRCResumeRequest
message or the RRCResumeRequest1 message.
[0333] If full configuration information (fullConfig) is included
in the RRCResume message, the UE performs a full configuration
procedure. Otherwise, if the UE receives the RRCResume message, the
UE may reconstruct the PDCP status and reset a COUNT value for SRB2
and all DRBs. The UE may reconstruct cell group configuration
information (cellGroupConfig) on the basis of stored UE context.
The UE indicates this to lower layer devices.
[0334] The UE may release the full UE connection resume identifier
(FullI-RNTI), the partitioned UE connection resume identifier
(ShortI-RNTI), and the stored UE context. At this time, the UE does
not release RAN notification area information
(RAN-NotificationAreaInfo).
[0335] If master cell group (masterCellgroup) configuration
information is included in the RRCResume message, the UE may
perform a cell group configuration procedure according to
configuration information.
[0336] If bearer configuration information (radioBearerConfig) is
included in the RRCResume message, the UE may configure a bearer
according to configuration information.
[0337] The UE may resume SRB2 and all DRBs.
[0338] If the UE stores cell reselection priority information, the
UE may discard the information. The information may be cell
reselection priority information, stored on the basis of
CellReselectionPriorities that may be included in the RRCRelease
message or received from another RAT.
[0339] If the timer T320 is being driven, the UE may stop it.
[0340] If frequency measurement configuration information
(measConfig) is included in the RRCResume message, the UE may
measure a frequency according to configuration information.
[0341] If the RRC connection is suspended, the UE may resume
frequency measurement.
[0342] The UE transitions to the RRC-connected mode in operation
2g-40. Accordingly, the UE indicates to higher layer devices that
the RRC connection, which had been suspended, is resumed. The UE
may stop the cell reselection procedure. The UE may consider a
currently accessed cell as a primary cell (PCell).
[0343] The UE transitioning to the RRC-connected mode may transmit
an RRC connection resume completion message (RRCResumeComplete
message) in operation 2f-45. Specifically, the UE configures the
RRCResumeComplete message as follows and transmits the
RRCResumeComplete message in operation 2g-45.
[0344] If higher layer devices provide a NAS PDU, the UE may insert
the NAS PDU into a dedicatedNAS-Message.
[0345] If higher layer devices or the NAS layer provide a PLMN, the
PLMN selected by the higher layer devices or the NAS layer may be
configured as a selectedPLMN-Identity on the basis of a
PLMN-IdentityList included in SIB1.
[0346] The gNB receiving the RRCResumeComplete message may transmit
an RRCRelease message including suspend configuration information
to the UE in operation 2g-50. Alternatively, if the UE does not
receive the RRCRelease message including the suspend configuration
information from the gNB in operation 2g-50, the UE may transmit
and receive data to and from the gNB. Alternatively, the gNB may
transmit another RRC message (for example, an RRCReject message or
an RRCRelease message including no suspend configuration
information) to the UE in operation 2g-50.
[0347] FIG. 2H illustrates a procedure in which the gNB releases
the connection of the UE and thus the UE switches from an
RRC-connected mode to an RRC-inactive mode and a procedure in which
the UE configures the connection with the gNB and thus switches
from the RRC-inactive mode to the RRC-connected mode according to
an embodiment of the disclosure.
[0348] Referring to FIG. 2H, a UE 2h-01 may make a network
connection with a gNB 2h-02 and transmit and receive data. If the
gNB should transition the UE to an RRC-inactive mode for a
predetermined reason, the gNB may transmit an RRC connection
release message (RRCRelease message) including suspend
configuration information (suspendConfig) in operation 2h-05 so as
to transition the UE to the RRC-inactive mode.
[0349] UE operation proposed when the UE receives the RRCRelease
message including the suspend configuration information in
operation 2h-05 is described below. The UE may perform some or all
of the following operations or may skip some operations.
[0350] If the RRCRelease message includes suspend configuration
information (suspendConfig), the UE may apply the received suspend
configuration information.
[0351] If there is no RAN notification area information
(RAN-NotificationAreaInfo) in the suspend configuration
information, the UE may apply a RAN notification area information
that the UE stores in advance. This is to support a delta
configuration for the UE because the size of the RAN notification
area information is big.
[0352] If there is RAN notification area information in the suspend
configuration information, the UE may update the stored values to
be new RAN notification area information included in the suspend
configuration information of the RRCRelease message.
[0353] If there is no timer value (for example, t380) in the
suspend configuration information, the UE may release t380 that has
been already stored.
[0354] If there is t3 80 in the suspend configuration information,
the UE may store t380 included in the suspend configuration
information of the RRCRelease message.
[0355] The UE may store at least one piece of information such as a
full UE connection resume identifier (Full-RNTI), a partitioned UE
connection resume identifier (ShortI-RNTI), NCC
(nextHopChainingCount), and a RAN paging cycle (RAN-PagingCycle)
included in the suspend configuration information.
[0356] Further, the UE may reset the MAC layer device. This is to
prevent unnecessary retransmission when the connection of data
stored in the HARQ buffer resumes.
[0357] The UE may re-establish the RLC layer devices for all SRBs
and DRBs. This is to prevent unnecessary retransmission when the
connection of data stored in the RLC buffer resumes and to
initialize parameters to be used in the future.
[0358] Unless the UE receives the RRCRelease message including the
suspend configuration information in response to an RRC connection
resume request message (RRCResumeRequest message), the UE may store
UE context. The UE context may include at least one of current RRC
configuration information, current security context information,
PDCP status information including ROHC status information, SDAP
configuration information, a UE cell identifier (C-RNTI) used in a
source cell (source PCell), a cell identity of a source cell
(CellIdentity), and a physical cell identity.
[0359] The UE may suspend all SRBs and DRBs except for SRB0.
[0360] The UE may start the timer t380 with a period LAN
notification area update timer value included in the suspend
configuration information.
[0361] The UE may report suspension of the RRC connection to a
higher layer.
[0362] The UE configures lower layer devices to stop an integrity
protection and encryption function.
[0363] Further, the UE may transition to the RRC-inactive mode.
[0364] As described above, the UE transitioning to the RRC-inactive
mode (in operation 2h-10) may reselect or switch/transition from a
current equivalent PLMN or a registered PLMN to another equivalent
PLMN during movement (in operation 2h-15).
[0365] At this time, if the NAS layer device of the UE detects it,
the NAS layer device may generate a NAS PDU and transmit the NAS
PDU to the AS layer device in operation 2h-20. Further, the UE may
provide a PLMN selected by the NAS layer of the UE to the AS layer
device of the UE in operation 2h-20.
[0366] The UE may configure mo-Singling as a reason to resume the
connection and may perform a connection resume process with the
gNB. The RRC-inactive mode UE may perform a random access procedure
and transmit an RRC message to the gNB, and the UE operation
proposed therefor is described below in operation 2h-25.
Specifically, the UE may perform at least one of the following
operations in connection with transmission of an RRCResume Request
message or an RRCResumeRequest1 message. Alternatively, the
following operations may be omitted.
[0367] If a useFullResumeID field is signaled through system
information (SIB1), the UE may select RRCResumeRequest1 as a
message to be transmitted to the gNB. The UE may configure
resumeIdentity as a full UE connection resume identifier value
(fullI-RNTI value). The fullI-RNTI value may be stored in the UE.
The UE may transmit the RRCResumeRequest1 message including the
resumeIdentity.
[0368] Otherwise, the UE may select an RRCResumeRequest as a
message to be transmitted to the gNB. The UE may configure
shortResumeIdentity as a partitioned UE connection resume
identifier value (shortI-RNTI value). The UE may transmit an
RRCResumeRequest message including shortResumeIdentity.
[0369] The UE may select mo-Signalling as a reason to resume the
connection (resumeCause).
[0370] If higher layer devices or the NAS layer of the UE provide a
PLMN, the PLMN selected by the higher layer devices or the NAS
layer of the UE may be configured as a selectedPLMN-Identity on the
basis of a PLMN-IdentityList included in SIB1. Accordingly, the UE
may prepare to include an RRCResumeRequest message or an
RRCResumeRequest1 message including the selectedPLMN-Identity.
[0371] The UE may calculate MAC-I and insert the MAC-I into the
selected message.
[0372] The UE may reconstruct RRC configuration information and
security context information on the basis of UE context except for
cell group configuration information (cellGroupConfig). The UE
context may be stored in the UE.
[0373] The UE updates a new KgNB security key on the basis of a
current KgNB security key, an NH (NextHop) value, and an NCC value.
The NCC value may be stored in the UE.
[0374] The UE may induce new security keys (K_RRCenc, K_RRC_nt,
K_Pint, and K_Upenc) to be used in an integrity protection and
verification procedure and an encryption and decryption procedure
using the newly updated KgNB security key.
[0375] The UE may resume the integrity protection and verification
procedure by applying the updated security keys and a previously
configured algorithm to all bearers except for SRB0 and then apply
integrity verification and protection to transmitted and received
data. This is to increase reliability and security of data
transmitted and received from SRB1 or DRBs.
[0376] The UE may resume an encryption and decryption procedure by
applying the updated security keys and a previously configured
algorithm to all bearers except for SRB0 and then apply encryption
and decryption to transmitted and received data. This is to
increase reliability and security of data transmitted and received
from SRB1 or DRBs.
[0377] The UE may reconstruct a PDCP status and reestablish PDCP
entities for SRB1.
[0378] Further, the UE resumes SRB1. This is because an RRCResume
message is received through SRB1 in response to an RRCResumeRequest
message or an RRCResumeRequest1 message to be transmitted.
[0379] Thereafter, the higher layer of the UE may transmit the
selected message to be transmitted to the gNB, that is, the
RRCResumeRequest message or the RRCResumeRequest1 message to lower
layer devices.
[0380] Accordingly, the UE may transmit the RRCResumeRequest
message or the RRCResumeRequest1 message to the gNB. Further, the
UE may transmit the RRCResumeRequest message or the
RRCResumeRequest1 message and start a timer T319.
[0381] The UE may perform a random access procedure to perform a
connection resume procedure with the gNB and transmit the
RRCResumeRequest message or the RRCResumeRequest1 message to the
gNB in operation 2h-25, and may receive an RRC connection resume
message (RRCResume message) in response thereto in operation 2h-30.
The UE operation proposed in such a case is described below in
operation 2h-30. The UE may perform at least one of the following
operations or the following operations may be omitted.
[0382] If the UE receives the RRCResume message, the UE stops the
timer T319 according to transmission of the RRCResumeRequest
message or the RRCResumeRequest1 message.
[0383] If full configuration information (fullConfig) is included
in the RRCResume message, the UE performs a full configuration
procedure. Otherwise, if the UE receives the RRCResume message, the
UE may reconstruct the PDCP status and reset a COUNT value for SRB2
and all DRBs. The UE may reconstruct cell group configuration
information (cellGroupConfig) on the basis of stored UE context.
The UE indicates this to lower layer devices.
[0384] The UE may release the full UE connection resume identifier
(FullI-RNTI), the partitioned UE connection resume identifier
(ShortI-RNTI), and the stored UE context. At this time, the UE does
not release RAN notification area information
(RAN-NotificationAreaInfo).
[0385] If master cell group (masterCellgroup) configuration
information is included in the RRCResume message, the UE may
perform a cell group configuration procedure according to
configuration information.
[0386] If bearer configuration information (radioBearerConfig) is
included in the RRCResume message, the UE may configure a bearer
according to configuration information.
[0387] The UE may resume SRB2 and all DRBs.
[0388] If the UE stores cell reselection priority information, the
UE may discard the information. The information may be cell
reselection priority information, stored on the basis of
CellReselectionPriorities that may be included in the RRCRelease
message or received from another RAT.
[0389] If the timer T320 is being driven, the UE may stop it.
[0390] If frequency measurement configuration information
(measConfig) is included in the RRCResume message, the UE may
measure a frequency according to configuration information.
[0391] If the RRC connection is suspended, the UE may resume
frequency measurement.
[0392] The UE transitions to the RRC-connected mode in operation
2h-35. Accordingly, the UE indicates to higher layer devices that
the RRC connection, which had been suspended, is resumed. The UE
may stop the cell reselection procedure. The UE may consider a
currently accessed cell as a primary cell (PCell).
[0393] The UE transitioning to the RRC-connected mode may transmit
an RRC connection resume completion message (RRCResumeComplete
message) in operation 2h-40. Specifically, the UE may configure the
RRCResumeComplete message as follows.
[0394] If a higher layer device provides a NAS PDU, the UE may
insert the NAS PDU into a dedicatedNAS-Message.
[0395] If higher layer devices or the NAS layer provide a PLMN, the
PLMN selected by the higher layer device or the NAS layer may be
configured as a selectedPLMN-Identity on the basis of a
PLMN-IdentityList included in SIB1.
[0396] The gNB receiving the RRCResumeComplete message may transmit
an RRCRelease message including suspend configuration information
to the UE in operation 2h-45. Alternatively, if the UE does not
receive the RRCRelease message including the suspend configuration
information from the gNB in operation 2h-45, the UE may transmit
and receive data to and from the gNB. Alternatively, the gNB may
transmit another RRC message (for example, an RRCReject message or
an RRCRelease message including no suspend configuration
information) to the UE in operation 2h-45.
[0397] An embodiment of operation of the terminal according to an
embodiment of the disclosure are as follows. The user equipment
(UE) can reselect another equivalent PLMN in an inactive state,
transmit, to a base station, a radio resource control (RRC) resume
request message including resume cause configured to mo-signaling
in case that a RAN-based notification area update procedure is
triggered, and receive, from the base station, an RRC resume
message.
[0398] An embodiment of operation of the base station according to
an embodiment of the disclosure are as follows. The base station
canan receive, from a UE, a radio resource connection (RRC) resume
request message including resume cause configured to mo-signaling
in case that another equivalent PLMN is reselected by an
inactive-state user equipment (UE) and a RAN-based notification
area update procedure is triggered, and transmit, to the UE, an RRC
resume message.
[0399] FIG. 2I is a block diagram illustrating the internal
structure of a UE according to an embodiment of the disclosure.
[0400] Referring to FIG. 21, the UE includes a radio-frequency (RF)
processor 2i-10, a baseband processor 2i-20, a memory 2i-30, and a
controller 2i-40. The controller 2i-40 may include a
multi-connection processor 2i-42 which performs a process for
operating in a multiple connection mode.
[0401] The RF processor 2i-10 performs a function for transmitting
and receiving a signal through a radio channel, such as band
conversion and amplification of a signal. That is, the RF processor
2i-10 up-converts a baseband signal provided from the baseband
processor 2i-20 into an RF band signal, transmits the RF band
signal through an antenna, and then down-converts the RF band
signal received through the antenna into a baseband signal. For
example, the RF processor 2i-10 may include a transmission filter,
a reception filter, an amplifier, a mixer, an oscillator, a
digital-to-analog convertor (DAC), and an analog-to-digital
convertor (ADC). Although FIG. 21 illustrates only one antenna, the
UE may include a plurality of antennas. The RF processor 2i-10 may
include a plurality of RF chains. Moreover, the RF processor 2i-10
may perform beamforming. For the beamforming, the RF processor
2i-10 may control a phase and a size of each signal transmitted and
received through a plurality of antennas or antenna elements. The
RF processor may perform MIMO and receive a plurality of layers
when performing the MIMO operation.
[0402] The baseband processor 2i-20 performs a function for
conversion between a baseband signal and a bitstream according to a
physical layer standard of the system. For example, in data
transmission, the baseband processor 2i-20 generates complex
symbols by encoding and modulating a transmission bitstream.
Further, in data reception, the baseband processor 2i-20
reconstructs a reception bitstream by demodulating and decoding a
baseband signal provided from the RF processor 2i-10. For example,
in an orthogonal frequency division multiplexing (OFDM) scheme,
when data is transmitted, the baseband processor 2i-20 generates
complex symbols by encoding and modulating a transmission
bitstream, maps the complex symbols to subcarriers, and then
configures OFDM symbols through an IFFT (inverse fast Fourier
transform) operation and a CP (cyclic prefix) insertion. Further,
when data is received, the baseband processor 2i-20 divides the
baseband signal provided from the RF processor 2i-10 in units of
OFDM symbols, reconstructs the signals mapped to the subcarriers
through a fast Fourier transform (FFT) operation, and then
reconstructs a reception bitstream through demodulation and
decoding.
[0403] The baseband processor 2i-20 and the RF processor 2i-10
transmit and receive signals as described above. Accordingly, the
baseband processor 2i-20 and the RF processor 2i-10 may be commonly
called a transmitter, a receiver, a transceiver, or a communication
unit. Further, at least one of the baseband processor 2i-20 and the
RF processor 2i-10 may include a plurality of communication modules
for supporting a plurality of different radio access technologies.
In addition, at least one of the baseband processor 2i-20 and the
RF processor 2i-10 may include different communication modules for
processing signals in different frequency bands. For example, the
different communication standards may include a WLAN (for example,
IEEE 802.11) and a cellular network (for example, LTE). Further,
the different frequency bands may include a super high frequency
(SHF) (for example, 2. NRHz, NRhz) band and a millimeter (mm) wave
(for example, 60 GHz) band.
[0404] The memory 2i-30 stores data such as a basic program, an
application, and setting information for the operation of the UE.
Particularly, the memory 2i-30 may store information related to a
second access node performing wireless communication through a
second radio access technology. The memory 2i-30 provides stored
data in response to a request from the controller 2i-40.
[0405] The controller 2i-40 controls the overall operation of the
UE. For example, the controller 2i-40 transmits and receives a
signal through the baseband processor 2i-20 and the RF processor
2i-10. The controller 2i-40 records data in the memory 2i-30 and
reads the data. To this end, the controller 2i-40 may include at
least one processor. For example, the controller 2i-40 may include
a communication processor (CP) that performs a control for
communication, and an application processor (AP) that controls a
higher layer such as an application.
[0406] FIG. 2J is a block diagram illustrating the configuration of
an NR gNB according to an embodiment of the disclosure.
[0407] Referring to FIG. 2J, the NR gNB includes an RF processor
2j-10, a baseband processor 2j-20, a backhaul transceiver 2j-30, a
memory 2j-40, and a controller 2j-50. The controller 2j-50 may
include a multi-connection processor 2j-52 which performs a process
for operating in a multiple connection mode.
[0408] The RF processor 2j-10 performs a function for transmitting
and receiving a signal through a wireless channel, such as band
conversion and amplification of a signal. That is, the RF processor
2j-10 up-converts a baseband signal provided from the baseband
processor 1j-20 into an RF band signal, transmits the RF band
signal through an antenna, and then down-converts the RF band
signal received through the antenna into a baseband signal. For
example, the RF processor 2j-10 may include a transmission filter,
a reception filter, an amplifier, a mixer, an oscillator, a DAC,
and an ADC. Although FIG. 2J illustrates only one antenna, the base
station may include a plurality of antennas. Further, the RF
processor 2j-10 may include a plurality of RF chains. The RF
processor 2j-10 may perform beamforming. For the beamforming, the
RF processor 2j-10 may control a phase and a size of each signal
transmitted and received through a plurality of antennas or antenna
elements. The RF processor may perform a downlink MIMO operation by
transmitting one or more layers.
[0409] The baseband processor 2j-20 performs a function of
conversion between a baseband signal and a bitstream according to a
physical-layer standard of the first radio access technology. For
example, in data transmission, the baseband processor 2j-20
generates complex symbols by encoding and modulating a transmission
bitstream. Further, in data reception, the baseband processor 2j-20
reconstructs a reception bitstream by demodulating and decoding a
baseband signal provided from the RF processor 2j-10. For example,
in an OFDM scheme, when data is transmitted, the baseband processor
2j-20 may generate complex symbols by encoding and modulating the
transmission bitstream, map the complex symbols to subcarriers, and
then configure OFDM symbols through an IFFT operation and CP
insertion. In addition, when data is received, the baseband
processor 2j-20 divides a baseband signal provided from the RF
processor 2j-10 in units of OFDM symbols, recovers signals mapped
with subcarriers through an FFT operation, and then recovers a
reception bitstream through demodulation and decoding. The baseband
processor 2j-20 and the RF processor 2j-10 transmit and receive
signals as described above. Accordingly, the baseband processor
2j-20 and the RF processor 2j-10 may be commonly referred to as a
transmitter, a receiver, a transceiver, a communication unit, or a
radio communication unit.
[0410] The backhaul transceiver 2j-30 provides an interface for
communicating with other nodes within the network. That is, the
backhaul transceiver 2j-30 converts a bitstream transmitted to
another node, for example, the SeNB or a core network from the
MeNB, into a physical signal and converts a physical signal
received from the other node into the bitstream.
[0411] The memory 2j-40 stores data such as a basic program, an
application, or configuration information for the operation of the
MeNB. Particularly, the memory 2j-40 may store information on a
bearer allocated to the access UE and a measurement result reported
by the accessed UE. The memory 2j-40 may store information which is
a reference for determining whether or not to allow multiple
connections to the UE. The memory 2j-40 provides stored data in
response to a request from the controller 2j-50.
[0412] The controller 2j-50 controls the overall operation of the
MeNB. For example, the controller 2j-50 transmits and receives a
signal through the baseband processor 2j-20 and the RF processor
2j-10 or through the backhaul transceiver 1j-30. The controller
2j-50 records data in the memory 2j-40 and reads the data. To this
end, the controller 2j-50 may include at least one processor.
[0413] While the disclosure has been shown described with reference
to various embodiments thereof, it will be understood by those
skilled in the art that various changes in form and details may be
made therein without departing from the spirit and scope of the
disclosure as defined by the appended claims and their
equivalents.
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