U.S. patent application number 17/339242 was filed with the patent office on 2021-11-18 for new radio pdcch to facilitate numerology operations.
The applicant listed for this patent is Convida Wireless, LLC. Invention is credited to Pascal M. Adjakple, Wei Chen, Ahmed ElSamadouny, Lakshmi R. Iyer, Salman Khan, Qing Li, Yifan Li, Joseph M. Murray, Allan Y. Tsai, Tianyi Xu, Guodong Zhang, Qian Zhang.
Application Number | 20210360595 17/339242 |
Document ID | / |
Family ID | 1000005740569 |
Filed Date | 2021-11-18 |
United States Patent
Application |
20210360595 |
Kind Code |
A1 |
Tsai; Allan Y. ; et
al. |
November 18, 2021 |
NEW RADIO PDCCH TO FACILITATE NUMEROLOGY OPERATIONS
Abstract
New radio download numerology allocation information may be
obtained through master information block data, system information
block data, radio resource control signals, or signals or a
physical downlink numerology indication channel, and used along
with a reference signal detected in a search space to obtain
resource element positions in an antenna port reference signal in a
resource block that belongs to a particular band slice according to
a reference signal allocation scheme for a band slice numerology. A
physical download control may then be decoded based upon one or
more resource elements of the reference signal, allowing the
connection of, e.g., an enhanced mobile broadband, massive machine
type communication, or ultra-reliable/low-latency application to a
communications network thereby. Alternatively, multiple physical
downlink control channels may be blindly demodulated at each of a
number calculated reference signal locations, and one channel
selected based on passing a cyclic redundancy check.
Inventors: |
Tsai; Allan Y.; (Boonton,
NJ) ; Iyer; Lakshmi R.; (King of Prussia, PA)
; Zhang; Guodong; (Woodbury, NY) ; Zhang;
Qian; (Basking Ridge, NJ) ; Adjakple; Pascal M.;
(Great Neck, NY) ; Li; Qing; (Princeton Junction,
NJ) ; Murray; Joseph M.; (Schwenksville, PA) ;
Xu; Tianyi; (San Jose, CA) ; Chen; Wei; (San
Diego, CA) ; ElSamadouny; Ahmed; (Austin, TX)
; Khan; Salman; (Richardson, TX) ; Li; Yifan;
(Conshohocken, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Convida Wireless, LLC |
Wilmington |
DE |
US |
|
|
Family ID: |
1000005740569 |
Appl. No.: |
17/339242 |
Filed: |
June 4, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16681182 |
Nov 12, 2019 |
11051293 |
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17339242 |
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15592997 |
May 11, 2017 |
10524244 |
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16681182 |
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62334935 |
May 11, 2016 |
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62401055 |
Sep 28, 2016 |
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62399921 |
Sep 26, 2016 |
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62416902 |
Nov 3, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W 72/046 20130101;
H04W 68/02 20130101; H04B 7/0639 20130101; H04L 5/0048 20130101;
H04B 7/0617 20130101; H04W 72/042 20130101; H04W 72/0446 20130101;
H04L 5/0053 20130101; H04B 7/0689 20130101; H04W 88/02
20130101 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04B 7/06 20060101
H04B007/06; H04W 68/02 20060101 H04W068/02 |
Claims
1. An apparatus comprising a processor, a memory, and communication
circuitry, the apparatus being connected to a network via its
communication circuitry, the apparatus further comprising
computer-executable instructions stored in the memory of the
apparatus which, when executed by the processor of the apparatus,
cause the apparatus to perform operations comprising: decoding a
physical slot format indicator channel to obtain structure
information pertaining to a first slot, the structure information
comprising a length of the first slot, a number of symbols for a
first transmission region, and/or a number of symbols for a second
transmission region; decoding the physical control format indicator
channel to obtain a size of a first control region; determining,
according to the slot structure and the size of the first control
region, a first search space; decoding multiple physical control
channel candidates within the first search space; checking each of
the physical control channel candidates for a first match with an
identifier associated with the apparatus; and determining, from a
matching physical control channel candidate of the first search
space, a second search space.
2. The apparatus of claim 1, wherein the operations further
comprise: blindly decoding multiple physical control channel
candidates within the second search space; checking each of the
physical control channel candidates within the second search space
for a second match with the identifier associated with the
apparatus; and determining, from a matching physical control
channel candidate of the second search space, a set of physical
control information.
3. The apparatus of claim 2, wherein: the matching physical control
channel candidate of the first search comprises an indicator of an
open-loop transmission mode; and the set of physical control
information comprises pre-coding matrix information.
4. The apparatus of claim 2, wherein: the matching physical control
channel candidate of the first search comprises an indicator of a
spatial multiplexing transmission mode; and the set of physical
control information comprises a number of layers and antenna port
indexes.
5. The apparatus of claim 2, wherein: the matching physical control
channel candidate of the first search comprises an indicator of a
beamforming transmission mode; and the set of physical downlink
control information comprises an antenna port index.
6. The apparatus of claim 1, wherein the physical control channel
candidates of the second search comprise a carrier indicator, a
resource allocation, a scheme for modulation and coding, a new data
indicator, a redundancy indicator, a hybrid automatic repeat
request process number, an assignment index, and/or a transmission
power control parameter.
7. The apparatus of claim 1, wherein the physical control channel
candidates of the first search space comprise an indicator of a
transmission mode.
8. The apparatus of claim 7, wherein the transmission mode is
selected from the list consisting of transmit diversity, open-loop
transmission, spatial multiplexing, and beamforming.
9. The apparatus of claim 1, wherein: the first search space is
common to a group of apparatuses; and the identifier associated
with the apparatus is a group identifier.
10. The apparatus of claim 1, wherein: the apparatus is a user
equipment; and the identifier of the apparatus is a user equipment
ID.
11. The apparatus of claim 1, wherein checking each of the physical
control channel candidates within the first and second search
spaces comprises computing a cyclic redundancy code.
12. The apparatus of claim 1, wherein the first control region is
in downlink.
13. The apparatus of claim 12, wherein one of the first
transmission region and/or the second transmission region in
downlink.
14. A method comprising: decoding a physical slot format indicator
channel to obtain structure information pertaining to a first slot,
the structure information comprising a length of the first slot, a
number of symbols for a first transmission region, and/or a number
of symbols for a second transmission region; decoding the physical
control format indicator channel to obtain a size of a first
control region; determining, according to the slot structure and
the size of the first control region, a first search space;
decoding multiple physical control channel candidates within the
first search space; checking each of the physical control channel
candidates for a first match with an identifier associated with the
apparatus; and determining, from a matching physical control
channel candidate of the first search space, a second search
space.
15. The method of claim 14, the method further comprise: blindly
decoding multiple physical control channel candidates within the
second search space; checking each of the physical control channel
candidates within the second search space for a second match with
the identifier associated with the apparatus; and determining, from
a matching physical control channel candidate of the second search
space, a set of physical control information.
16. The method of claim 15, wherein: the matching physical control
channel candidate of the first search comprises an indicator of an
open-loop transmission mode; and the set of physical control
information comprises pre-coding matrix information.
17. The method of claim 15, wherein: the matching physical control
channel candidate of the first search comprises an indicator of a
spatial multiplexing transmission mode; and the set of physical
control information comprises a number of layers and antenna port
indexes.
18. The method of claim 15, wherein: the matching physical control
channel candidate of the first search comprises an indicator of a
beamforming transmission mode; and the set of physical downlink
control information comprises an antenna port index.
19. The method of claim 14, wherein the first control region is in
downlink.
20. The method of claim 14, wherein the first transmission region
and/or the second transmission region is in the downlink.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 16/681,182 filed Nov. 1, 2019 which is a
continuation of U.S. patent application Ser. No. 15/592,997 filed
May 11, 2017 which claims the benefit of priority to U.S.
Provisional Patent Application No. 62/334,935, filed May 11, 2016,
U.S. Provisional Patent Application No. 62/401,055, filed Sep. 28,
2016, U.S. Provisional Patent Application No. 62/399,921, filed
Sep. 26, 2016, and U.S. Provisional Patent Application No.
62/416,902, filed Nov. 3, 2016, the disclosures of which are
incorporated by reference in their entireties.
BACKGROUND
[0002] Existing and proposed telecommunications networks and
subnetwork, may operate in accordance with various standards, such
as LTE, 4G, 5G, and 3GPP, to support diverse applications, such as
live communication, entertainment media transmission, computer data
transfer, and Internet-of-things (IoT), Web-of-things, and
machine-to-machine (M2M) operations. Various standards include
numerologies for the allocation of communications resources by
subcarrier and timeslot. Various standards also include mechanisms
for Physical Downlink Control Channel (PDCCH) operations.
SUMMARY
[0003] A New Radio Physical Downlink Control Channel (NR-PDCCH) may
incorporate a number of features to facilitate multiple numerology
operations to support such diverse uses as enhanced Mobile
Broadband (eMBB), massive Machine Type Communication (mMTC), and
ultra-reliable/low-latency applications (UR/LL). A user equipment
(UE) device may, for example, blindly decode its own NR-PDCCH
regardless of use cases or numerology. Alternatively, numerology
allocation may be signaled on the MIB or SIB for the scenarios
whereby numerology allocation is semi-statically updated. As
another alternative, numerology allocation may be signaled on a
Physical Downlink Numerology Indication Channel (PDNICH) for the
scenarios whereby numerology allocation is dynamically updated.
[0004] The NR-PDCCH may be decoded on the fly using a new radio
reference signal (NR-RS) for demodulating NR-PDCCH. For example,
The NR-RS and NR-PDCCH are using the same pre-coding/beamforming.
The NR-RS may be masked with a UE-specific sequence
[0005] The NR-PDCCH may support flexible frame structure and
FDD/TDD hybrid multiplexing. For example, the UE search space may
be predefined by higher layer signaling, such as Radio Resource
ContrCol (RRC.)
[0006] Some DCI may be split into multicast-NR-PDCCH and
pre-coded-NR-PDCCH portions. For example, the multicast-NR-PDCCH
may provide the DL grant location and NR-RS resource information
for the pre-coded-NR-PDCCH of that grant. Once the terminal decodes
this multicast-NR-PDCCH, the terminal may determine the location of
a pre-coded NR-PDCCH and decode it to determine the transmission
mode, NR-RS information for the layers, antenna configuration,
etc.
[0007] In NR, it is desired that dynamic transmission mode
switching be supported which takes advantage of the fast fading
channel, and may provide more flexibility and improve a user's
experience.
[0008] In order to address the problems associated with the large
latency of transmission mode switching in the current 3GPP system,
the following example mechanisms to enable dynamic transmission
mode switching, while not increasing the number of blind decoding
attempts, are herein proposed.
[0009] A new downlink control signaling, Physical Slot Format
Indicator Channel (PSFICH), to inform the UE about necessary
information of the current slot, such as the length of the slot,
the symbols for downlink transmission region, and the symbols for
uplink transmission region. The PSFICH may be transmitted at the
first symbol of each slot. The PSFICH may also be encoded in low
coding rate and transmitted in transmit diversity mode to improve
reliability;
[0010] A two-tier NR PDCCH may be used to support dynamic
transmission mode switching and reduce the blind decoding attempts.
The first tier NR PDCCH may be transmitted in the downlink control
region, and its search space could be common and/or UE-specific.
The first tier NR PDCCH may have a unified NR DCI format, which
does not depend on the transmission mode. The first tier NR PDCCH
may also contain the necessary information for the second tier NR
PDCCH blind decoding, such as the index of the NR DCI format used
for the second tier NR PDCCH and the search space indicator used to
configure the second tier NR PDCCH search space. The second tier NR
PDCCH may contain all of the required information for the scheduled
downlink transmission. The second tier NR PDCCH may be transmitted
in the control region or the data region. The second tier NR PDCCH
search space may be UE-specific and may be determined by the search
space indicator in the first tier NR PDCCH, the current slot
structure, and/or the UE ID. For different transmission modes, the
second tier NR PDCCH may have different DCI formats, which are
signaled in the first tier NR PDCCH. The transmit diversity scheme
or beam based diversity scheme may be applied to signals in the
control region, and the NR PDCCH located in the data region may be
configured with the same transmission mode as the data channel.
[0011] Another option to signal the index of the second tier NR DCI
format, which may be through the MAC CE. In this case, the first
tier NR PDCCH may not be necessary; NR transmission modes, the
number of which is much less the number of transmission modes in
the current LTE; and NR DCI formats for different NR transmission
modes to support the two-tier NR PDCCH.
[0012] In order to address the need for enhanced initial access
signal design that supports beamforming for NR networks, the
following solutions are proposed:
[0013] A DL initial access signal which contains a DL
synchronization channel (signals), a beam reference signal and a
PBCH channel; a DL initial access signal which is carried by a DL
beam sweeping block, each beam sweeping block containing either a
single OFDM or multiple OFDM symbols; a DL beam sweeping subframe
which may contain multiple beam sweeping blocks; DL synchronization
channels PSS and SSS which can be placed at different OFDM symbols;
a beam sweeping block which contains only one DL synchronization
channel; a beam reference signal and a PBCH which may co-exist in
the same OFDM symbol or in different OFDM symbols; and a PBCH which
might have a different transmission period than the DL
synchronization channel and beam reference signals.
[0014] If the DL synchronization channel carries both the cell and
beam ID, then the UE can detect the cell and beam ID from the DL
synchronization channel. Therefore, the UE can know which DL beam
sweeping block is detected and is able to calculate the timing
offset between the detected beam sweeping block to the DL sweeping
subframe.
[0015] If the DL synchronization channel only carries the cell ID,
then the UE can detect the beam ID from the beam reference signal.
Therefore, the UE can know which DL beam sweeping block is detected
and is able to calculate the timing offset between the detected
beam sweeping block to the DL sweeping subframe.
[0016] Mechanisms for Control Channel Designs can include
techniques to assign resources for NR-DCI and waveform for UL
signaling. Mechanisms to aid control channel estimation and
allocation of UL and DL resources within sub-bands can limit the
computational burden on the UE.
[0017] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter. Furthermore, the claimed subject matter is not
limited to limitations that solve any or all disadvantages noted in
any part of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 illustrates LTE PDCCH for indicating DL PDSCH
resource allocation.
[0019] FIG. 2 is a flow diagram of an example UE blind PDCCH
decoding method for an LTE UE.
[0020] FIG. 3 shows an example of resource allocations for legacy
LTE PDCCH and EPDCCH.
[0021] FIG. 4 is a block diagram of an example configuration of a
5G transmitter for multiplexing different numerologies.
[0022] FIG. 5 shows an example configuration of multiplexed
numerologies for various use cases.
[0023] FIG. 6 shows an example time varying band slice
configuration for different numerologies.
[0024] FIG. 7 shows an example of numerology slicing in time
only.
[0025] FIG. 8 shows an example of numerology slicing in both time
and frequency resource.
[0026] FIG. 9 shows an example of resource assignment in a DL based
on a bandsliceConfig-k.
[0027] FIG. 10 is a flow chart of an example UE method to obtain
the band slice configuration through system information where the
information is configured through the MIB.
[0028] FIG. 11 is a flow chart of an example method where a
bandsliceConfig-k may be implicitly signaled to the UE.
[0029] FIG. 12 shows an example configuration of a bTTI carrying
the PDNICH in a band.
[0030] FIG. 13 shows an example UE method to obtain the band slice
configuration through PDNICH-numerology.
[0031] FIG. 14 shows an example of multiple PDNICH resources
located in respective band slices.
[0032] FIG. 15 shows an example UE method to obtain a band slice
configuration by blindly decoding the PDNICH in all possible
locations.
[0033] FIG. 16 illustrates an example of band slices within a
bFrame.
[0034] FIG. 17 shows an example 5G system supporting three
different numerologies with three UEs.
[0035] FIG. 18 is a flow chart of an example UE method for decoding
NR-PDCCH.
[0036] FIG. 19 shows an example configuration where multiple
multicast-NR-PDCCH are carried in different symbols within a band
slice.
[0037] FIG. 20 shows example symbols for multiple
multicast-NR-PDCCH regions configured through NR-PCFICH.
[0038] FIG. 21 shows an example configuration of a band slice in a
bTTI.
[0039] FIG. 22 shows an example configuration indicating the
pre-coded-NR-PDCCH in a self-contained manner within the DL grant
to the UE.
[0040] FIG. 23 is a flow chart of an example method involved for
decoding downlink control information.
[0041] FIG. 24 shows example slot structures with dynamic and
static slot structures.
[0042] FIG. 25 shows example slot structures indicated by PSFICH
with CFI.
[0043] FIG. 26 shows an example beam based Space-Frequency Block
Code (SFBC).
[0044] FIG. 27 shows an example beam based Frequency Switch
Transmit Diversity (FSTD).
[0045] FIG. 28 shows an example transmission mode
activation/deactivation MAC control element of one octet.
[0046] FIG. 29 shows an example transmission mode
activation/deactivation MAC control element of four octets.
[0047] FIG. 30 illustrates an example procedure for two-tier NR
PDCCH.
[0048] FIG. 31 is an example DL transmission chain for a transport
block.
[0049] FIG. 32 is an example of a MAC PDU.
[0050] FIG. 33 shows an example of a Common control search space
for eMBB and URLL.
[0051] FIG. 34 shows an example of a URLL NR-PDCCHs being mapped in
the leading symbols.
[0052] FIG. 35 shows an example of URLL data resources in the
leading symbols of the subframe.
[0053] FIG. 36 shows an example of Resource multiplexing between
UEs.
[0054] FIG. 37 shows an example of Low code rate NR-PDCCH split
into RVs in frequency.
[0055] FIG. 38 shows an example of a URLL UE procedure for decoding
its NR-PDCCHs.
[0056] FIG. 39 shows an example of a eMBB UE procedure for decoding
its NR-PDCCHs.
[0057] FIG. 40 shows an example of a Low code rate NR-PDCCH split
into RVs in time.
[0058] FIG. 41 shows an example of a URLL UE procedure for decoding
NR-PDCCH by iterating through all NR-PDCCHs of a given RV.
[0059] FIG. 42 shows an example of a URLL UE procedure for decoding
NR-PDCCH by iterating through all RVs of a NR-PDCCH.
[0060] FIG. 43 shows an example of a low code rate NR-PDCCH split
into RVs, using both time and frequency resources.
[0061] FIG. 44 shows an example of multiple DL control regions
within a subframe.
[0062] FIG. 45 shows an example of data and control regions
multiplexed in the same symbol.
[0063] FIG. 46 shows an example of a control region that may not
allocate a grant in symbols preceding it.
[0064] FIG. 47 shows an example in which the 2nd control region
punctures eMBB data.
[0065] FIG. 48 shows an example of subsequent control regions being
indicated by former control regions in a subframe.
[0066] FIG. 49 shows an example of NR-PCFICH configuring the
control regions in a subframe.
[0067] FIG. 50 shows an example of multiple DL control regions,
where 2nd and 3rd control regions are for URLLC only.
[0068] FIG. 51 shows an example of multiple UL control regions
being configured within a subframe.
[0069] FIG. 52 shows an example of multiple DL control regions
configuring UL control regions in a subframe.
[0070] FIG. 53 shows an example of a NR DL control search space
with beam sweeping.
[0071] FIG. 54 shows an example of a UE procedure for NR DL control
channel.
[0072] FIG. 55 is a diagram that illustrates control information
transmitted on beams followed by shared channel transmission.
[0073] FIG. 56A and FIG. 56B are diagrams that illustrate some
NR-DCI which may be repeated on the beams. FIG. 56A is a diagram
that illustrates NR-DCI for a UE is repeated in all beams. FIG. 56B
is a diagram that illustrates NR-DCI for a UE is transmitted only
on 2 out of 4 beams.
[0074] FIG. 57 is a diagram that illustrates an example scenario
where each beam in the control region is followed by a shared
channel transmission.
[0075] FIG. 58 is a diagram that illustrates an example scenario
where a control RS or beam RS may be used to estimate the
channel.
[0076] FIG. 59 is a diagram that illustrates an example scenario
where a control DMRS is used in UE-specific manner to decode the
NR-DCI.
[0077] FIG. 60 is a diagram that illustrates an example scenario
where a control DMRS shared between control and data region if they
are pre-coded in the same way.
[0078] FIG. 61 is a diagram that illustrates an example scenario
where a beam sweeping through control symbols of same
numerology.
[0079] FIG. 62 is a diagram that illustrates an example scenario
where a beam sweeping through control signals of different
numerologies.
[0080] FIG. 63 is a diagram that illustrates an example scenario
where a sub-band allocation to a UE to limit the search space for
control signaling.
[0081] FIG. 64 is a diagram that illustrates an example scenario
where sub-band allocation to common control signaling.
[0082] FIG. 65 is a diagram that illustrates an example scenario
where a sub-band operation for shared channel.
[0083] FIG. 66 illustrates an example communications system.
[0084] FIG. 67 is a block diagram of an example apparatus or device
configured for wireless communications such as, for example, a
wireless transmit/receive unit (WTRU).
[0085] FIG. 68 is a system diagram of a first example radio access
network (RAN) and core network.
[0086] FIG. 69 is a system diagram of a second example radio access
network (RAN) and core network.
[0087] FIG. 70 is a system diagram of a third example radio access
network (RAN) and core network.
[0088] FIG. 71 is a block diagram of an exemplary computing system
in which one or more apparatuses of communications networks may be
embodied, such as certain nodes or functional entities in the RAN,
core network, public switched telephone network (PSTN), Internet,
or other networks.
DETAILED DESCRIPTION
[0089] New radio download numerology allocation information may be
obtained through master information block data, system information
block data, radio resource control signals, or a physical downlink
numerology indication channel, and used along with a reference
signal detected in a search space to obtain resource element
positions in an antenna port reference signal in a resource block
that belongs to a particular band slice according to a reference
signal allocation scheme for a band slice numerology. A physical
download control may then be decoded based upon one or more
resource elements of the reference signal, allowing the connection
of, e.g., an enhanced mobile broadband, massive machine type
communication, or ultra-reliable/low-latency application to a
communications network thereby.
[0090] Alternatively, multiple physical downlink control channels
may be speculatively demodulated at each of a number calculated
reference signal locations within one or more search spaces. A
physical downlink control channel may be selected based on passing
a cyclic redundancy check. The cyclic redundancy check may be
masked with an identifier of the apparatus.
[0091] Reference signal detection may be achieved by correlating a
received signal of the resource element with a specific reference
signal of the apparatus. The search space may be provided by a
radio resource control signal. The physical download control
channel may include a reference signal using the same pre-coding or
beamforming.
[0092] For ultra-reliable/low-latency applications, for example,
the reference signal data may be frequency division multiplexed
only, and not time division multiplexed, to meet latency
requirements. For enhanced mobile broadband applications, for
example, the reference signal and data may be multiplexed in both
frequency and time division.
[0093] The physical downlink control channel may be multicast, and
may comprise a downlink grant location and reference signal
resource information, allowing the location of a pre-coded physical
downlink control channel to be determined, and a transmission mode
or antenna configuration to be determined thereby.
[0094] In the current LTE, switching between different transmission
modes is configured by RRC signaling, and within each configured
transmission mode, a UE is allowed to fall back from the configured
transmission mode to a default transmit diversity scheme. As the
exact subframe number when this configuration takes effect in the
UE is not specified, there is a period when the network and the UE
may have different understandings of which transmission mode is
configured. Therefore, the UE may suffer from the latency of
semi-static RRC signaling.
[0095] An objective of the Study Item on New Radio (NR) Access
Technology is to identify and develop technology components needed
for systems operating at frequencies up to 100 GHz. For example,
see 3GPP TR 38.913, Study on Scenarios and Requirements for Next
Generation Access Technologies; (Release 14), V0.3.0, as well as
RP-161214, Revision of SI: Study on New Radio Access Technology,
NTT DOCOMO. To compensate for the increased path loss in these High
Frequency NR (HF-NR) systems, beamforming is expected to be widely
used. However, the existing initial access signal design such as DL
synchronization, reference signal and PBCH design, which is based
on omnidirectional or sector-based transmission, does not support
the functions required for beamforming based access (e.g., beam
sweeping, beam pairing, beam training, etc.)
[0096] Downlink Control Information (DCI) is a predefined format in
which the DCI is formed and transmitted in Physical Downlink
Control Channel (PDCCH). The DCI format tells the UE how to get its
data which is transmitted on Physical Downlink Shared Channel
(PDSCH) in the same subframe. It carries the details for the UE
such as number of resource blocks, resource allocation type,
modulation scheme, redundancy version, coding rate, etc., which
help UE find and decode PDSCH from the resource grid. There are
various DCI formats used in LTE in PDCCH.
[0097] Currently 3GPP standardization efforts are underway to
define the NR frame structure. Consensus is to build the so called
`self-contained` time intervals for NR. A self-contained time
interval is understood to contain the control information for a
grant, the data and its acknowledgement (i.e., ACK/NACK) all within
a time interval and is expected to have configurable UL/DL/side
link allocations and reference signals within its resources. See,
e.g., 3GPP R1-164694 Frame Structure Requirements, Qualcomm, May
2016.
[0098] Table 1 is a list of acronyms relating to service level
technologies that may appear in the description below. Unless
otherwise specified, the acronyms used herein refer to the
corresponding term listed below.
TABLE-US-00001 TABLE 1 Acronyms 2D Two-Dimensional 3D
Three-Dimensional A/N ACK/NACK, Acknowledgement/Non-
acknowledgement AAS Active Antenna System AoA Angle or Arrival AoD
Angle of Departure API Application Program Interface AS Access
Stratum BCCH Broadcast Control Channel BCH Broadcast Channel BL
Bandwidth reduced Low complexity CE Control Element CMAS Commercial
Mobile Alert System CN Core Network CoMP Coordinated Multi Point CP
Cyclic Prefix CQI Channel Quality Indication C-RNTI Cell
Radio-Network Temporary Identifier CRS Cell-specific Reference
Signals CSG Closed Subscriber Group CSI Channel State Information
CSI-RS Channel State Information Reference Signals DCI Downlink
Control Information DL Downlink DL-SCH Downlink Shared Channel
DM-RS Demodulation Reference Signals DRX Discontinuous Reception
E2E End to End EAB Extended Access Barring eCell Extended Cell eDRX
Extended Discontinuous Reception eMBB enhanced Mobile Broadband ENB
Evolved Node B ePDCCH Enhanced Physical Downlink Control Channel
ETWS Earthquake and Tsunami Warning System E-UTRA Evolved Universal
Terrestrial Radio Access E-UTRAN Evolved Universal Terrestrial
Radio Access Network FD Full-Dimension FDD Frequency Division
Duplex FFS For Further Study GUI Graphical User Interface HARQ
Hybrid Automatic Repeat Request HD High Definition ID
Identification IE Information element IMT International Mobile
Telecommunications IOT Internet of Things KP Kronecker Product KPI
Key Performance Indicators LC-MTC Low Cost or Low Complexity
Machine-Type Communications LTE Long term Evolution MAC Medium
Access Control MBB Mobile Broadband MBSFN Multicast-Broadcast
Single-Frequency Network MCL Maximum Coupling Loss MCS Modulation
and Coding Scheme MIB Master Information Block MIMO Multiple-Input
and Multiple-Output MME Mobility Management Entity mMTC massive
Machine Type Communication MTC Machine-Type Communications MVNO
Mobile Virtual Network Operator NAS Non-access Stratum NB Narrow
Beam NB-IOT Narrow band IoT NDI New Data Indicator NEO Network
Operation NGMN Next Generation Mobile Networks NR New Radio, i.e.,
5G NR-PDCCH New Radio Physical Downlink Control Channel OCC
Orthogonal Cover Codes OFDM Orthogonal frequency division
multiplexing PBCH Physical Broadcast Channel PCFICH Physical
Control Format Indicator Channel PDCCH Physical Downlink Control
Channel PDNICH Physical Downlink Numerology Indication Channel
PDSCH Physical Downlink Shared Data Channel PHICH Physical Hybrid
ARQ Indicator Channel PLMN Public Land Mobile Network PMCH Physical
Multicast Channel PMI Precoder Matrix Indication PRACH Physical
Random Access Channel PRB Physical Resource Block PRS Positioning
Reference Signals PUCCH Physical Uplink Control Channel PUSCH
Physical Uplink Shared Channel RAN Radio Access Network RAT Radio
Access Technology RB Resource block RE Resource Element RI Rank
Indication RNTI Radio Network Temporary Identifier R-PDCCH
Relay-Physical Downlink Control Channel RRC Radio Resource Control
RS Reference Signal RSRP Reference Signal Received Power RSRQ
Reference Signal Received Quality RSSI Received Signal Strength
Indicator RV Redundancy Version SC-FDMA Single carrier frequency
division multiple access SFN System Frame Number SI System
Information SIB System Information Block SIBe SIB Essential SIPF SI
Provisioning Function SI-RNTI System Information RNTI SISO
Single-Input and Single-Output SMARTER Feasibility Study on New
Services and Markets Technology SPS-RNTI Semi persistent scheduling
RNTI SR Scheduling Request SRS Sounding Reference Signal sTTI Short
TTI TAU Tracking Area Update TBS Transport Block Size TDD Time
Division Duplex TPC Transmit Power Control TRP Transmission and
Reception Point TRP Transmission and Reception Point TTI
Transmission Time Interval UE User Equipment UHD Ultra-high
definition UL Uplink UR/LL Ultra-Reliable - Low Latency URLLC
Ultra-Reliable and Low Latency Communications vTTI Variable TTI WB
Wide Beam WLAN Wireless Local Area Network WRC Wireless Planning
Coordination
[0099] In LTE, PDCCH is used to indicate UL and DL
grants/transmission. FIG. 1 illustrates LTE PDCCH for indicating DL
PDSCH resource allocation. PDCCH carries the control information
about the data being transmitted on the current subframe and the
information about the resources which UEs need to use for the
uplink data. PDCCH carries a message called downlink control
information (DCI) which includes resource assignments for a UE or
group of UE's.
[0100] The are several DCI formats in LTE. Format 0 is used for
transmission of Uplink Shared Channel (UL-SCH) allocation. Format 1
is used for transmission of DL-SCH allocation for Single Input
Multiple Output (SIMO) operation. Format 1A is used for compact
transmission of DL-SCH allocation for SIMO operation or allocating
a dedicated preamble signature to a UE for random access. Format 1B
is used for transmission control information of Multiple Input
Multiple Output (MIMO) rank 1 based compact resource assignment.
Format 1C is used for very compact transmission of PDSCH
assignment. Format 1D same as format1B with additional information
of power offset. Format 2 and Format 2A for transmission of DL-SCH
allocation for closed and open loop MIMO operation, respectively.
Format 2B is used for the scheduling of dual layer transmission
(antenna ports 7 & 8). Format 2C is used for the scheduling of
up to 8 layer transmission (antenna ports 7 to 14) using TM9.
Format 2D is used for the scheduling of up to 8 layer transmission
(antenna ports 7 to 14) using TM10. Format 3 and Format 3A are used
for transmission of TPC command for an uplink channel. Format 4 is
used for the scheduling of PUSCH with multi-antenna port
transmission mode.
[0101] Allocation of PDCCH resources happens in terms of CCE
(Control Channel Elements). One CCE=nine continuous REGs (Resource
element Groups)=36 REs, i.e., 1 REG=4 RE. PDCCH uses the resources
present in first n OFDM symbols where n--Value present in PCFICH,
e.g., the number of OFDM symbols. The number of CCEs present to
transmit the control information will be variable depending on the:
PCFICH value; bandwidth of the system from 1.4 MHz to 20 MHz; and
the number of antenna ports present which in turn will affect the
reference signals present.
[0102] The total number of REs available is determined from the
first n OFDM symbols, where n is from the value of PCFICH. Total
REs allocated for PDCCH may be equal to n.times.x.times.y, where n
is a PCFICH value, x is the number of subcarriers in 1 RB, and y is
the total number of RBs in a system BW. For an example, suppose n=3
and system BW=10 MHz. The total number of available
REs=3.times.12.times.50=1800 REs in n=3 OFDM symbols. The available
allocable REs for PDCCH may be expressed as total REs: the number
of REs used for RS, the number of REs used in PHICH, together with
the number of REs used in PCFICH. Therefore, the number of
available PDCCH CCE's=REs for PDCCH/36.
[0103] There are two PDCCH search spaces: the common search space
and the UE-specific search space. A UE is required to monitor both
common and UE-specific search space. There might be overlap between
common & UE-specific search spaces for a UE.
[0104] For the common search space, eNodeB uses only aggregation
level 4 and 8 for the allocation in common search space. The
maximum number of CCE's present in common search space is fixed as
16. If the total number of CCE's available in the system are less
than 16 for any bandwidth then all the CCE's will be present in
common search space. The position of Common search space CCE's is
always fixed starting from the first CCE index.
[0105] The UE-specific search space may carry DCIs for UE-specific
allocations using the UE's assigned C-RNTI, semi-persistent
scheduling (SPS C-RNTI), or initial allocation (temporary C-RNTI).
The UE monitors the UE-specific search space at all aggregation
levels (1, 2, 4, and 8).
[0106] FIG. 2 is a flow diagram of an example UE blind PDCCH
decoding method for an LTE UE. The UE may do blind decoding either
because the UE has no information about the CCE's used by PDCCH,
the UE does not know the aggregation level used by eNodeB, or the
UE does not have information about the DCI format used by
eNodeB
[0107] The UE is only informed of the number of OFDM symbols within
the control region of a subframe and is not provided with the
location of its corresponding PDCCH. The UE finds its PDCCH by
monitoring a set of PDCCH candidates in every subframe. This is
referred to as blind decoding.
[0108] The eNodeB may calculate CCE indexes for a UE, e.g., with an
Aggregation Level with a value of 1, 2, 4 or 8. PDCCH candidates
may include a number of CCE indexes searched by a UE in a subframe
for a particular search space. The PDCCH Format may be a DCI format
such as 0, 1, 2, 3, or 4.
[0109] In addition to the conventional PDCCH of R8, the EPDCCH is
available in R11. FIG. 3 shows an example of resource allocations
for legacy LTE PDCCH and EPDCCH. The EPDCCH uses the PDSCH
resources to transmit DL control information to increase the
control channel capacity. The ePDCCH is especially useful when
cross-carrier scheduling is used for carrier aggregation.
[0110] For R11, the EPDCCH is configured to be used for dedicated
search space only, i.e., there is no E-PDCCH being included in
common search space.
[0111] The fundamental resource units used in a legacy PDCCH are
the resource element groups (REGs). Comparable to the PDCCH, the
basic resources of an EPDCCH are the enhanced resource element
groups (EREGs) which are used to build the enhanced control channel
element (ECCE). An EPDCCH is transmitted using one or more enhanced
CCEs or ECCEs. An ECCE is made up of four or eight EREGs. There are
16 possible EREGs (0, 1, 2, . . . 15) in a PRB pair. A CCE has 36
REs. The number of available REs in an ECCE varies, depending on:
the size of Legacy control region; sub-frame type; PSS/SSS/PBCH in
the PRB; number of CRS ports; and the number of CSI-RS ports.
[0112] There are a number of possibilities for EREG and ECCE
mappings. The fundamental motivations for different mappings
methods are: to achieve simplicity and common design for any
configuration, e.g., localized and distributed transmission; to
achieve frequency diversity gain; and support ECCE level or PRB
level ICIC.
[0113] EPDCCH transmissions categorized as either distributed or
localized. In localized transmission, ECCE resources are mapped to
a single or adjacent PRB pair. An EPDCCH may make use of ECCEs
within one PRB pair at lower aggregation level or use adjacent PRB
pairs if more ECCEs are needed in case of higher aggregation level.
Localized transmission is more beneficial in situations where there
is effective PDCCH for LTE-A Systems channel state information
(CSI) feedback. This also leverages frequency-selective scheduling
and beamforming. For each serving cell, the subframes in which the
UE monitors EPDCCH UE-specific search spaces are configured by
higher layers. The UE monitors a set of EPDCCH candidates on one or
more activated serving cells as configured by higher layer
signaling for control information, where monitoring implies
attempting to decode each of the EPDCCHs in the set according to
the monitored DCI formats. For EPDCCH type=`Localized`, the EPDCCH
is transmitted on a single antenna port chosen from ports 107, . .
. 110 as a function of a number of parameters including the RNTI.
For EPDCCH type=`Distributed`, the EPDCCH is transmitted on two
antenna ports, either {107,109} for normal cyclic prefix or
{107,108} for extended cyclic prefix. The EPDCCH and its DMRS must
be beam-formed and mapped to physical antennas for transmission.
The beamforming vectors here are chosen in accordance with TS36.101
Annex B.4.4 for distributed transmission and TS36.101 Annex B.4.5
for localized transmission. The EPDCCH and its DMRS must undergo
the same beam-forming, therefore they may be processed together
when applying the beamforming.
[0114] It is expected that ultra-reliable, low-latency
applications, such as drone control and remote surgery, and some
mMTC applications, such as robotic control and industry automation,
will significantly benefit from reduced control and user plane
latencies. So there is considerable interest in having the UL and
DL numerologies for 5G accommodate such use cases without requiring
backward compatibility with LTE.
[0115] 3GPP TR 38.913, Study on Scenarios and Requirements for Next
Generation Access Technologies, Release 14, V0.2.0, defines
scenarios and requirements for next generation access technologies.
The following are excerpts of the Key Performance Indicators (KPI)
section of 3GPP TR 38.913 that are relevant to low latency design.
[0116] "7.5 User Plane Latency [ . . . ] For URLLC the target for
user plane latency should be 0.5 ms for UL, and 0.5 ms for DL.
Furthermore, if possible, the latency should also be low enough to
support the use of the next generation access technologies as a
wireless transport technology that can be used within the next
generation access architecture. [ . . . ] NOTE1: The reliability
KPI also provides a latency value with an associated reliability
requirement. The value above should be considered an average value
and does not have an associated high reliability requirement. [ . .
. ] For eMBB, the target for user plane latency should be 4 ms for
UL, and 4 ms for DL. [ . . . ] NOTE2: For eMBB value, the
evaluation needs to consider all typical delays associated with the
transfer of the data packets in an efficient way (e.g. applicable
procedural delay when resources are not preallocated, averaged HARQ
retransmission delay, impacts of network architecture)."
[0117] A network may be "sliced," where each slice is composed of a
collection of logical network functions that supports the
communication service requirements of a particular use case or set
of use cases. For example, a 3GPP operator's network may be divided
into a critical MTC slice, a massive MTC, and MBB slice, whereby it
is possible to direct UEs to selected slices in a way that fulfill
operator or user needs, e.g., based on subscription or UE type.
Network slicing primarily targets a partition of the core network.
However, the Radio Access Network (RAN) may need specific
functionality to support multiple slices, or even partitioning of
resources for different network slices. See, e.g., 3GPP TR 22.891,
Feasibility Study on New Services and Markets Technology Enablers
(SMARTER), Stage 1, Release 14, V-1.1.0.
[0118] Potential network slicing service requirements are defined
in 3GPP TR 22.891, whereby the 3GPP system shall allow the operator
to compose network slices, independent sets of network functions,
e.g., such as parameter configurations for hosting multiple
enterprises or Mobile virtual network operators (MVNOs), network
functions from different vendors, etc. Under 3GPP TR 22.891, the
operator shall be able to dynamically create network slices to form
a complete, autonomous, and fully operational network customized to
cater for different diverse market scenarios. The 3GPP system shall
be able to identify certain UEs and subscribers to be associated
with a particular network slice. The 3GPP system shall be able to
enable a UE to obtain service from a specific network slice e.g.,
based on subscription or UE type.
[0119] In Long Term Evolution (LTE), multi-antenna techniques are
used to achieve improved system performance, including improved
system capacity (more users per cell) and improved coverage
(possibility for larger cells), as well as improved service
provisioning (e.g., higher per-user data rates). The availability
of multiple antennas at the transmitter and/or the receiver can be
utilized in different ways to achieve different aims. For example,
see E. Dahlman, S. Parkvall, J. Skold, "4G LTE/LTE-Advanced for
Mobile Broadband," second edition, 2014. These aims include antenna
diversity, beamforming, and spatial multiplexing.
[0120] In antenna diversity, multiple antennas at the transmitter
and/or the receiver can be used to provide additional diversity
against fading on the radio channel.
[0121] In antenna beamforming, multiple antennas at the transmitter
and/or the receiver can be used to "shape" the overall antenna beam
in a certain way--for example, to maximize the overall antenna gain
in the direction of the target receiver or to suppress specific
dominant interfering signals.
[0122] In antenna spatial multiplexing, the simultaneous
availability of multiple antennas at the transmitter and receiver
can be used to create multiple parallel communication "channels"
over the radio interface. This provides high data rates within a
limited bandwidth, which is referred to as Multiple-Input and
Multiple-Output (MIMO) antenna processing.
[0123] In LTE, there are currently ten different transmission
modes, which are summarized in Table 2. The transmission mode is
configured to the UE through RRC signaling in LTE.
TABLE-US-00002 TABLE 2 Transmission Modes in LTE LTE Transmission
Rel Mode Description 8 1 Single-antenna transmission 8 2 Transmit
diversity 8 3 Open-loop codebook-based pre-coding in the case of
more than one layer, transmit diversity in the case of rank-one
transmission 8 4 Closed-loop codebook-based pre-coding 8 5
Multi-user-MIMO version of transmission mode 4 8 6 Special case of
closed loop codebook-based pre-coding limited to single-layer
transmission 8 7 Non-codebook-based pre-coding supporting
single-layer PDSCH transmission 9 8 Non-codebook-based pre-coding
supporting up to two layers 10 9 Non-codebook-based pre-coding
supporting 8 layers 11 10 Extension of transmission mode 9 for
enhanced support of different means of DL multi-point coordination
and transmission, also referred to as CoMP
[0124] The Downlink Control Information (DCI) is a predefined
format in which the DCI is formed and transmitted in a Physical
Downlink Control Channel (PDCCH). The DCI format tells the UE how
to get its data which is transmitted on Physical Downlink Shared
Channel (PDSCH) in the same subframe. It carries the details for
the UE such as number of resource blocks, resource allocation type,
modulation scheme, redundancy version, coding rate, etc., which
help UE find and decode PDSCH from the resource grid. There are
various DCI formats used in LTE in PDCCH. The different DCI formats
are included in Table 3.
TABLE-US-00003 TABLE 3 DCI Formats DCI Format Usage Major Contents
Format 0 UL Grant. Resource RB Assignment, Transmit Allocation for
UL Data Power Control (TPC), PUSCH Hopping Flag Format 1 DL
Assignment for RB Assignment, TPC, Single-Input and Hybrid
Automatic Repeat Single-Output (SISO) Request (HARQ) Format 1A DL
Assignment for RB Assignment, TPC, SISO (compact) HARQ Format 1B DL
Assignment for RB Assignment, TPC, MIMO with Rank 1 HARQ, PMI
Format 1C DL Assignment for RB Assignment SISO (minimum size)
Format 1D DL Assignment for RB Assignment, TPC, Multi User MIMO
HARQ, DL Power Offset Format 2 DL Assignment for RB Assignment,
TPC, Closed Loop MIMO HARQ, pre-coding Information Format 2A DL
Assignment for RB Assignment, TPC, Open Loop MIMO HARQ, pre-coding
Information Format 2B DL Assignment for RB Assignment, TPC,
Transmission Mode 8 HARQ, pre-coding (Dual layer beamforming)
Information Format 2C DL Assignment for RB Assignment, TPC,
Transmission Mode 9 HARQ, pre-coding Information Format 3 TPC
Commands for Power Control Only PUCCH and PUSCH with 2 bit power
adjustment Format 3A TPC Commands for Power Control Only PUCCH and
PUSCH with 1 bit power adjustment Format 4 UL Assignment for UL RB
Assignment, TPC, MIMO (up to 4 layers) HARQ, pre-coding
Information
[0125] Each PDCCH supports multiple DCI formats and the format used
is a priori unknown to the UE. Therefore, the UE needs to blindly
detect the format of the PDCCHs. To reduce the number of blind
decoding attempts, LTE defines search spaces as a set of candidate
control channels formed by control-channel elements (CCEs) at a
given aggregation level, which the UE is supposed to attempt to
decode. Each UE has UE-specific search spaces, which are determined
by the UE ID and the subframe number. In addition, common search
spaces are defined for the PDCCH, and all UEs monitor the
candidates in the common search spaces for PDCCH.
[0126] The DCI formats to be monitored in the UE-specific search
spaces depend on the transmission modes configured to the UE.
[0127] System Information (SI) is the information broadcast by the
Evolved Universal Terrestrial Radio Access Network (E-UTRAN) that
needs to be acquired by the UE to be able to access and operate
within the network. SI is divided into the MasterinformationBlock
(MIB) and a number of SystemInformationBlocks (SIBs). A high level
description of the MIB and SIBs is provided in 3GPP TS 36.300,
Overall description; Stage 2 (Release 13), V13.3.0, and is
summarized in Table 4. Detailed descriptions are available in 3GPP
TS 36.331, Radio Resource Control (RRC); Protocol specification
(Release 13), V13.0.0.
TABLE-US-00004 TABLE 4 System Information Infor- mation Block
Description MIB Defines the most essential physical layer
information of the cell required to receive further system
information SIB1 Contains information relevant when evaluating if a
UE is allowed to access a cell and defines the scheduling of other
system information SIB2 Radio resource configuration information
that is common for all UEs SIB3 Cell re-selection information
common for intra-frequency, inter-frequency and/or inter-RAT cell
re-selection (i.e., applicable for more than one type of cell
re-selection but not necessarily all) as well as intra-frequency
cell re- selection information other than neighboring cell related
SIB4 Neighboring cell related information relevant only for
intra-frequency cell re-selection SIB5 Information relevant only
for inter-frequency cell re- selection (i.e., information about
other E UTRA frequencies and inter-frequency neighboring cells
relevant for cell re-selection) SIB6 Information relevant only for
inter-RAT cell re-selection (i.e., information about UTRA
frequencies and UTRA neighboring cells relevant for cell
re-selection) SIB7 Information relevant only for inter-RAT cell
re-selection (i.e., information about GERAN frequencies relevant
for cell re-selection) SIB8 Information relevant only for inter-RAT
cell re-selection (i.e., information about CDMA2000 frequencies and
CDMA2000 neighboring cells relevant for cell re-selection) SIB9
Home eNB name (HNB Name) SIB10 Earthquake and Tsunami Warning
System (ETWS) primary notification SIB11 ETWS secondary
notification SIB12 Commercial Mobile Alert System (CMAS)
notification SIB13 Information required to acquire the MBMS control
information associated with one or more MBSFN areas SIB14 Extended
Access Barring (EAB) parameters SIB15 MBMS Service Area Identities
(SAI) of the current and/or neighboring carrier frequencies SIB16
Information related to GPS time and Coordinated Universal Time
(UTC) SIB17 Information relevant for traffic steering between
E-UTRAN and WLAN SIB18 Indicates E-UTRAN supports the Sidelink UE
information procedure and may contain sidelink communication
related resource configuration information SIB19 Indicates E-UTRAN
supports the sidelink UE information procedure and may contain
sidelink discovery related resource configuration information SIB20
Contains the information required to acquire the control
information associated transmission of MBMS using Single Cell-Point
to Multi-point (SC-PTM)
[0128] Currently, 3GPP standardization efforts are underway to
design the framework for beamformed access. The characteristics of
the wireless channel at higher frequencies are significantly
different from the sub-6 GHz channel that LTE is currently deployed
on. The key challenge of designing the new Radio Access Technology
(RAT) for higher frequencies will be in overcoming the larger
path-loss at higher frequency bands. In addition to this larger
path-loss, the higher frequencies are subject to an unfavorable
scattering environment due to blockage caused by poor diffraction.
Therefore, MIMO/beamforming is essential in guaranteeing sufficient
signal level at the receiver end. For example, see R1-164013,
Framework for beamformed access, Samsung
[0129] Relying solely on MIMO digital pre-coding used by digital BF
to compensate for the additional path-loss in higher frequencies
seems not enough to provide similar coverage as that below 6 GHz.
Thus, the use of analog beamforming for achieving additional gain
can be an alternative in conjunction with digital beamforming. A
sufficiently narrow beam should be formed with multiple antenna
elements, which is likely to be quite different from the one
assumed for the LTE evaluations. For large beamforming gain, the
beam-width correspondingly tends to be reduced, and hence the beam
with the large directional antenna gain cannot cover the whole
horizontal sector area specifically in a 3-sector configuration.
The limiting factors of the number of concurrent high gain beams
include the cost and complexity of the transceiver
architecture.
[0130] From these observations above, multiple transmissions in
time domain with narrow coverage beams steered to cover different
serving areas are necessary. Inherently, the analog beam of a
subarray can be steered toward a single direction at the time
resolution of an OFDM symbol or any appropriate time interval unit
defined for the purpose of beam steering across different serving
areas within the cell. Hence the number of subarrays determines the
number of beam directions and the corresponding coverage on each
OFDM symbol or time interval unit defined for the purpose of beams
steering. In some literature, the provision of multiple narrow
coverage beams for this purpose has been called "beam sweeping."
For analog and hybrid beamforming, the beam sweeping seems to be
essential to provide the basic coverage in NR. For analog and
hybrid beamforming with massive MIMO, multiple transmissions in
time domain with narrow coverage beams steered to cover different
serving areas is essential to cover the whole coverage area within
a serving cell in NR.
[0131] One concept closely related to beam sweeping is the concept
of beam pairing which is used to select the best beam pair between
a UE and its serving cell. This can be used for control signaling
or data transmission. For the downlink transmission, a beam pair
will consist of a UE RX beam and a NR-Node TX beam while for uplink
transmission, a beam pair will consist of a UE TX beam and a
NR-Node RX beam.
[0132] Another related concept is the concept of beam training
which is used for beam refinement. For example, a coarser sector
beamforming may be applied during the beam sweeping and sector beam
pairing procedure. Beam training may then follow where, for
example, the antenna weights vector is refined, followed by the
pairing of high gain narrow beams between the UE and NR-Node.
[0133] R2-162571, Introduction of Virtual Cell, CATT, defines a
virtual cell as multiple TRPs (Transmission Reception Points) with
the same cell ID under the control of a central unit. Common
information or cell-level information is transmitted in a large
cell area and dedicated data is transmitted from adjacent TRPs near
the UE with realization of CP/UP split.
[0134] 3GPP TR 38.913, Study on Scenarios and Requirements for Next
Generation Access Technologies; (Release 14), V0.3.0, defines
scenarios and requirements for next generation access technologies.
The Key Performance Indicators (KPIs) for eMBB, URLLC and mMTC
devices are summarized in Table 5.
TABLE-US-00005 TABLE 5 KPIs for eMBB, URLLC and mMTC Devices Device
KPI Description Requirement eMBB Peak data Peak data rate is the
highest theoretical data rate which 20 Gbps for rate is the
received data bits assuming error-free conditions downlink and
assignable to a single mobile station, when all 10 Gbps for
assignable radio resources for the corresponding link uplink
direction are utilized (e.g., excluding radio resources that are
used for physical layer synchronization, reference signals or
pilots, guard bands and guard times). Mobility Mobility
interruption time means the shortest time 0 ms for intra-
interruption duration supported by the system during which a user
system time terminal cannot exchange user plane packets with any
mobility base station during transitions. Data Plane For the eMBB
value, the evaluation needs to consider 4 ms for UL, Latency all
typical delays associated with the transfer of the and 4 ms for
data packets in an efficient way (e.g., applicable DL procedural
delay when resources are not pre-allocated, averaged HARQ
retransmission delay, impacts of network architecture). URLLC
Control Control plane latency refers to the time to move from a 10
ms Plane battery efficient state (e.g., IDLE) to start of Latency
continuous data transfer (e.g., ACTIVE). Data Plane For URLLC, the
target for user plane latency for UL 0.5 ms Latency and DL.
Furthermore, if possible, the latency should also be low enough to
support the use of the next generation access technologies as a
wireless transport technology that can be used within the next
generation access architecture. Reliability Reliability can be
evaluated by the success probability 1-10-5 of transmitting X bytes
(1) within 1 ms, which is the within 1 mS. time it takes to deliver
a small data packet from the radio protocol layer 2/3 SDU ingress
point to the radio protocol layer 2/3 SDU point of the radio
interface, at a certain channel quality (e.g., coverage-edge).
NOTE1: Specific value for X is FFS. mMTC Coverage "Maximum coupling
loss" (MCL) in uplink and 164 dB downlink between device and Base
Station site (antenna connector(s)) for a data rate of [X bps],
where the data rate is observed at the egress/ingress point of the
radio protocol stack in uplink and downlink. UE Battery User
Equipment (UE) battery life can be evaluated by 15 years Life the
battery life of the UE without recharge. For mMTC, UE battery life
in extreme coverage shall be based on the activity of mobile
originated data transfer consisting of [200 bytes] Uplink (UL) per
day followed by [20 bytes] Downlink (DL) from Maximum Coupling Loss
(MCL) of [tbd] dB, assuming a stored energy capacity of [5Wh].
Connection Connection density refers to total number of devices 106
Density fulfilling specific Quality of Service (QoS) per unit
devices/km2 area (per km2). QoS definition should take into account
the amount of data or access request generated within a time t_gen
that can be sent or received within a given time, t_sendrx, with x%
probability.
[0135] A network slice is composed of a collection of logical
network functions that support the communication service
requirements of particular use case(s). It shall be possible to
direct terminals to selected slices in a way that fulfil operator
or user needs, for example, based on subscription or terminal type.
The network slicing primarily targets a partition of the core
network, but it is not excluded that Radio Access Network (RAN) may
need specific functionality to support multiple slices or even
partitioning of resources for different network slices For example,
see 3GPP TR 22.891, Feasibility Study on New Services and Markets
Technology Enablers (SMARTER); Stage 1 (Release 14), V1.3.2.
[0136] 3GPP TR 38.913 Study on Scenarios and Requirements for Next
Generation Access Technologies; (Release 14), V0.2.0, defines
scenarios and requirements for next generation access technologies.
The following are excerpts of the Key Performance Indicators (KPI)
section of 3GPP TR 38.913 that impose new requirements that are
relevant to the 5G MIMO procedure:
[0137] 7.1 Peak data rate: the target for peak data rate may be 20
Gbps for downlink and 10 Gbps for uplink, for example;
[0138] 7.2 Peak Spectral efficiency: the target for peak spectral
efficiency may be 30 bps/Hz for downlink and 15 bps/Hz for
uplink;
[0139] 7.10 Coverage: the target for coverage may be 164 dB, for
example;
[0140] 7.12 UE energy efficiency: UE energy efficiency means the
capability of a UE to sustain much better mobile broadband data
rate while minimizing the UE modem energy consumption; and
[0141] 7.19 Network energy efficiency: the capability is to
minimize the RAN energy consumption while providing a much better
area traffic capacity.
[0142] The 3GPP TR 22.863 Feasibility Study on New Services and
Markets Technology Enablers--Enhanced Mobile Broadband; Stage 1
(Release 14), V0.3.1, identifies the use cases and consolidates
requirements for the following families for the eMBB scenario:
Higher Data Rates, Higher Density, Deployment and Coverage, and
Higher User Mobility.
[0143] Control channels for UL and DL NR will have a beam centric
architecture. The DL control signaling on multiple beams in
currently undefined in NR. NR-DCI may be pre-coded; so solutions
are required to support channel estimation for DL control signals.
On the UL, multiple waveforms may be supported--CP-OFDM and
DFTS-OFDM are the supported alternatives. NR must support
mechanisms to assign a waveform to the UE.
[0144] It is projected that 5G will support various use cases,
eMBB, mMTC and UR/LL. The solutions in standard LTE may be
inadequate to address the scenarios that 5G multiple numerologies
approaches seek to address. Also lacking are solutions to
seamlessly multiplex applications using different numerologies
simultaneously.
[0145] One challenge presented is the design of the DL control
channel to support multiple numerologies. 5G is expected to support
multiple numerologies of TTIs, e.g., variations in CP length,
subcarrier spacing or symbol duration, and the number of symbols in
the TTI. Multiple numerologies may be multiplexed on to the same
time-frequency resource grid.
[0146] FIG. 4 shows an example configuration of a 5G transmitter
multiplexing different numerologies. The numerologies are described
in Table 6. The data channel and control channel in 4G LTE use one
fixed common numerology in a cell. The design of PDCCH in 4G LTE
considers only one fixed numerology in the cell. In a 5G system,
use cases/services with different numerologies and latency
requirements may be supported simultaneously. This also implies
their corresponding downlink control channels will have different
TTI lengths and subcarrier spacing/symbol lengths. UEs of each use
case need to know where to find their DL control channels. The
design of DL control channel in 5G should support multiplexing of
use cases such as eMBB, mMTC, and UR/LL.
TABLE-US-00006 TABLE 6 Example numerologies supported in 5G 5G
numerology 5G numerology 5G numerology case 1 case 2 case 3
Subcarrier .DELTA.f = 15 KHz, .DELTA.f = 30 KHz .DELTA.f = 60 KHz
with spacing with y = 1 with y = 2 with y = 4 T.sub.guard(z)
T.sub.guard(z = 1) = T.sub.guard(z = 2) = T.sub.guard(z = 3) = 4.7
.mu.S 2.35 .mu.s 1.175 .mu.s Minimum 71.37 .mu.s 35.68 .mu.s 17.57
.mu.s TTI
[0147] FIG. 5 shows an example configuration of multiplexed
numerologies for 5G belonging to numerologies of case-1, case-2 and
case-3.
[0148] Another challenge presented is DL control channel to support
flexible frame structure in 5G. 5G provides various levels of QoS
with bundled TTI designs for latency/efficiency tradeoff. In
addition, 5G may support service-aware TTI multiplexing and
self-contained TDD subframes.
[0149] However, if 5G inherits the PDCCH design in LTE, it will
inherit certain shortcomings. For example, UEs may need to monitor
the full bandwidth since the PDCCH is transmitted on the full
bandwidth. For 5G mMTC, it may not be feasible to monitor full
carrier BW. Further, in LTE, PDSCH demodulation is based on DM-RS
while the PDCCH decoding is based on CRS, i.e., always-on. This
kind of decoding latency and hierarchy might not be suitable for
UR/LL in 5G. Also, LTE uses strict time domain division between
control and data channels. 5G may require support for flexible time
frame structures. Further still, EPDCCH beamforming with the PDSCH
support may be required on demand.
[0150] Herein, the term "band slice" may refer to time-frequency
resources configured for each numerology or the network slices
configured for each numerology or group of UEs using each
numerology. The term "bTTI" refers to the base transmission time
interval in a 5G frame. A bTTI is a unit of a transmission time
interval during which the band slice configuration cannot change. A
band slice may be defined, for example, by one of the following
parameters, or a combination thereof: symbol duration; subcarrier
spacing; CP duration; resources in the time and frequency domain;
adjoining guard band on top and bottom of the band slice; bTTI
duration; TTI duration of each numerology; and/or the number of
symbols.
[0151] The band slices in a DL may be configurable either
dynamically or semi-statically, thereby providing flexibility in
assigning resources to different network slices. FIG. 6 shows an
example configuration of time varying frequency assignments to
different band slices in a DL resource grid. Every bTTI shows a
different band slice configuration. Additionally, within each bTTI
the resources are multiplexed in frequency.
[0152] The resource grid within a bTTI may be partitioned across
the band slices in other ways, such as through time multiplexing,
as shown in FIG. 7. Alternatively, the resource grid within a bTTI
may be partitioned across the band slices by both time and
frequency multiplexing as showing in FIG. 8.
[0153] System information, such as the MIB, may provide numerology
allocation information in a network where the numerology
configuration is semi-statically updated. Accordingly, the system
information may carry information pertaining to the number of
permissible band slices, e.g., numBandslices K, and the
configurations, e.g., bandsliceConfig-k where k=1, 2, . . . K. FIG.
9 shows an example of resource assignment in a DL based on a
bandsliceConfig-k. Table 7 shows an example configuration of the
fields defining the k.sup.th band slice for a 20 MHz carrier and
shows the corresponding pictorial depiction. Updates to the
configuration may be made through RRC and MAC CE.
TABLE-US-00007 TABLE 7 Configuration of bandsliceConfig-k
bandsliceConfig-k cpConfig-k = 2.35 (.mu.s) subcarrierSpacing = 30
(KHz) guardBandTop = 90 (KHz) guardBandBottom = 90 (KHz)
numResources = 120 (30 KHz subcarriers) startResource = 7.5 (MHz
from the center of band)
[0154] FIG. 10 shows an example UE method to obtain the band slice
configuration through system information through the MIB. The UE
decodes the MIB then holds the numerology configuration. The UE
then decodes the NR-PDCCH of its band slice to obtain the control
information.
[0155] FIG. 11 illustrates an example method where the field of
bandsliceConfig-k may be implicitly signaled to the UE, rather than
explicitly. For example, the UE may have a set of permissible
combinations of band slices C, and then the UE may receive an index
pointing to one of the permissible combinations with set C. The set
of permissible combinations C may be defined, e.g., in a
"numerologyBook" as C=(combination 1, combinaiton2, . . .
combination n, . . . , . . . combination N) where the index of
permissible combinations is n=1, 2, . . . N. The set of permissible
combinations C may be specified and known to both the UE and the
network, e.g., eNB or the equivalent 5G RAN node.
[0156] Numerology assignment for each band slice in a network where
the numerology configuration is dynamically updated may be
allocated dynamically via a Physical Downlink Numerology Indication
Channel (PDNICH). Here, each bTTI has its own PDNICH defining the
location of the band slices in that bTTI. For example, PDNICH
carries the indices of the signaling fields shown in Table 7 for
each of the K band slices. These configurations may be signaled on
MIB or SIB, for example. Further, The PDNICH may be located in the
first symbol of the bTTI in order to minimize the latency in
processing the DCI and data.
[0157] Resources for PDNICH may be allocated by a common PDNICH
allocation method, whereby PDNICH for all the band slices is
signaled in a common numerology through a
"PDNICH-numerology-Config," for example, that is received by all or
multiple network slices. The PDNICH resources and numerology is
indicated to the terminals through the system information. For
example, the system information may indicate the fields shown in
Table 8 to define the resources of PDNICH.
[0158] The resources with respect to the starting location and
number of resources may be predefined in the 3GPP standards. Then,
given the beginning frequency location and subcarrier spacing, the
terminal may determine the PDNICH resources without ambiguity.
[0159] FIG. 12 shows an example configuration of a bTTI carrying
the PDNICH in the band slice-2. FIG. 13 shows the UE method used to
obtain the band slice configuration through PDNICH-numerology. The
UE obtains the PDNICH numerology through system information. The UE
may also obtain PDNICH numerology by decoding the PDNICH from each
bTTI the UE decodes the PDNICH. The UE may then decode the downlink
information from its respective NR-PDCCH.
TABLE-US-00008 TABLE 8 Configuration of PDNICH-Numerology-Config
PDNICH-Numerology-Config cpConfig-k = 2.35 (.mu.s)
subcarrierSpacing-k = 30 (KHz) startingFrequencyResource = 0.96
(MHz from the center of band)
[0160] Resources for PDNICH may be allocated by a per-slice PDNICH
allocation scheme, whereby PDNICH is configured separately for each
of the numerologies supported by the cell. FIG. 14 shows an example
of multiple PDNICH resources located in respective band slices.
[0161] Multiple possible resources may be predefined for each
PDNICH in the 3GPP standards, and the bTTI may carry one such
configuration for each PDNICH. The terminal may blindly decode all
the possible configurations corresponding to the network slice that
it is allocated to in order to determine the PDNICH resources and
its content for that network slice. This solution limits the search
space of the terminal to its network slice.
[0162] FIG. 15 shows the UE as an example method to obtain the band
slice configuration by blindly decoding the PDNICH in all possible
locations. Here the UE blindly decodes a search space every bTTI to
obtain the PDNICH and then proceeds to decode the control
information.
[0163] In an example solution, the index into the numerologyBook
may be signaled through the PDNICH.
[0164] Band slices may hop in frequency according to a predefined
pattern available in the 3GPP standards, or based on a pattern
provided through system information and updated through MAC CE. For
example, consider a signaling interval "bFrame" defined as the
duration of B bTTIs. The network may configure the 0th bTTI of the
bFrame. Then locations of the band slices for subsequent bTTIs may
occur according to a predefined pattern. This solution provides
minimal signaling overhead while supporting gain through frequency
hopping. FIG. 16 illustrates hopping within a bFrame.
[0165] In 5G, the downlink reference signal, downlink control
channel, and downlink data channel may follow the self-contained
and lean-carrier design principles. The transmission of NR-PDCCH,
for example, may be more flexible than E-PDCCH in LTE and take the
advantage of pre-coding or beamforming of the downlink data
channel. The 5G demodulation reference signal (NR-RS) and NR-PDCCH
may use the same pre-coding/beamforming such that NR-PDCCH may be
demodulated using NR-RS. The NR-RS is transmitted when only there
is a DL data transmission.
[0166] 3GPP NR may specify NR-RS allocation/configurations for each
supported numerology. In other words, RE positions of each antenna
port's NR-RS may be specified for each supported numerology, e.g.,
subcarrier spacing, number of symbols, CP length, etc. For example,
for UR/LL, the NR-RS and data may be multiplexed in a frequency
division manner to meet latency requirements. For eMBB, the NR-RS
and data may be multiplexed in both frequency and time division.
Thereby different numerologies may have different NR-RS
allocation/configurations schemes. NR-RS allocation schemes may be
specified in the standards by using frequency shift (in the unit of
subcarrier) and time shift (in the unit of symbol) in the rules of
mapping NR-RS to resource elements. For example, frequency shift
and time shift are defined as functions of parameters such as cell
ID, numerology index, etc.
[0167] The sequence of NR-RS may re-use the design of UE-specific
RS defined in Section 6.10.3 of 3GPP TS 36.211, where the
pseudo-random sequence generator for the RS is initialized with a
function of Cell ID and UE ID. To decode the NR-PDCCH dynamically,
a UE may first calculate the NR-RS location based on RE or RBG
location.
[0168] Blind decoding for the NR-PDCCH may be achieved by first
detecting the presence of an NR-RS, and then using the detected
NR-RS to decode NR-PDCCH.
[0169] Alternatively, without detecting the NR-RS, a UE may
implicitly assume that NR-RS and NR-PDCCH are both transmitted, and
decode NR-PDCCH.
[0170] A method including first detecting NR-RS may proceed
according to the following example. In Step 1, the UE obtains
potential positions or search space of NR-RS. Upon obtaining the DL
numerology allocation information through MIB/SIB, RRC signals or
PDNICH, the UE may obtain the RE positions of each antenna port's
NR-RS in each resource block (RB) that belongs to a particular band
slice according to the NR-RS allocation scheme for the band
slice/numerology. The UE may obtain the potential positions or
search space of its NR-RS, such as on several REs used by several
different antenna ports. The starting location based on RBG of the
UE-specific search space may be varied for each TTI or
subframe.
[0171] In Step 2, the UE detects a specific NR-RS. For each
possible NR-RS position, the UE will detect whether its NR-RS is
actually transmitted or not. Detection may be achieved by
correlating the received signals on these REs with UE's specific
NR-RS. Once the presence of its NR-RS is detected, the UE will
proceed to Step 3 to decode NR-PDCCH. If no UE-specific NR-RS is
detected, then UE will not proceed to decode NR-PDCCH.
[0172] In Step 3, the UE undertakes blind decoding of the NR-PDCCH.
Upon detecting the NR-RS, the corresponding NR-PDCCH's starting
location may be derived from RE positions of the NR-RS. For
example, a NR-PDCCH starting location in time and frequency
resource may be obtained according to a predefined formula of the
detected NR-RS positions. This formula may be UE-specific. In this
way, a UE may avoid trying blind decoding all NR-PDCCH possible
candidates before detecting a UE-specific NR-RS for demodulating
NR-PDCCH.
[0173] Blind decoding for the NR-PDCCH may be achieved without
first detecting the NR-RS, and may proceed according to the
following example. To decode the proposed NR-PDCCH dynamically, a
UE (user) first calculates the NR demodulation reference signal
(NR-RS) location. In this option, UE assume the NR-RS and NR-PDCCH
are present at the same time, i.e., that NR-RS and NR-PDCCH are
present simultaneously. The search space of NR-PDCCH and NR-RS may
be either configured by RRC or a predefined formulation. Once the
channel estimation is obtained from NR-RS, the UE may start to
demodulate the NR-PDCCH. In this setup, the UE may start to blind
decode for all possible NR-PDCCH candidates. With the possibilities
of different RNTIs, NR-PDCCH candidates, NR-DCI and NR-PDCCH
formats, a significant number of attempts may be required to
successfully decode the NR-PDCCH. To overcome this complexity, the
UE first tries to blindly decode the first CCE in the control
channel candidate set of a subframe. If the blind decoding fails,
the UE tries to blindly decode the first 2, 4 then 8 CCEs
sequentially, where the starting location may be given by a
predefined function, for UE-specific scheme. The NR-PDCCH candidate
sets correspond to different NR-PDCCH formats. If the UE fails to
decode any NR-PDCCH candidate for a given PDCCH format it tries to
decode candidates for other NR-PDCCH formats. This process is
repeated for all possible NR-PDCCH formats.
[0174] If one of decoded NR-PDCCH candidates pass the CRC, then it
may be declared a successful decoding of NR-PDCCH. The CRC may be
masked with UE's ID, such as a UE-RNTI, to ensure which NR-PDCCH is
belonging to the UE. Once the NR-PDCCH is successfully decoded, the
UE may start to de-map the content of decoded PDCCH to the
transmitted DCI format.
[0175] FIG. 17 shows an example 5G system supporting three
different numerologies with three UEs. A UE with numerology 1 will
try to decode NR-PDCCH with a predefined formula to calculate all
possible NR-PDCCH starting frequency. After the UE obtains the
channel estimation information from NR-RS then it is able to
demodulate the NR-PDCCH candidates simultaneously. If none of
decoded CRC are passed, then this UE may continue monitoring
NR-PDCCH with other supporting numerology if necessary. If there is
a CRC pass among one of NR-PDCCH candidates, then this UE may start
to map the decoded information into DCI.
[0176] FIG. 17 show an example NR-PDCCH for supporting multiplexed
numerologies and use cases. FIG. 18 shows an example UE method for
decoding NR-PDCCH.
[0177] In addition to the NR-PDCCH, 5G may use a new radio Physical
Control Format Indicator channel (NR-PCFICH) as a physical channel
carrying information on how many contiguous symbols are used to
signal the NR-PDCCH. Within a bTTI, one or more NR-PDCCH symbols
may be configured in each band slice to carry control information
such as power-control commands and UL, DL grant-related information
for the terminals configured for that numerology. These NR-PDCCH
regions may be broadcast or multicast so that all intended
terminals may monitor the region for a grant and decode the
corresponding control information. Herein, the term
"multicast-NR-PDCCH" refers to a contiguous region of NR-PDCCH
signals signaled in this manner. A multicast-NR-PDCCH may configure
a DL grant in one or more symbols locations following the
multicast-NR-PDCCH and up to the symbol carrying the next
multicast-NR-PDCCH.
[0178] In a manner similar to decoding PDCCH in LTE, the terminals
may blindly decode the multicast-NR-PDCCH to see if they have a
grant. The multiple NR-PDCCH opportunities may occur with a TTI
corresponding to a single numerology enabling time-slicing to
support sTTIs of multiple durations and hence multiple use
cases.
[0179] FIG. 19 shows an example configuration of symbols carrying
multiple multicast-NR-PDCCH in different symbols within a band
slice. The multicast-NR-PDCCH in symbol 0, 1 may indicate a DL
grant in one or more symbols from the set {3,4} in the bTTI while
the multicast-NR-PDCCH in symbol 8 may indicate a DL grant in one
or more symbols from the set {9,10,11}. Depending on amount of
control information, the multicast-NR-PDCCH region in each band
slice may have varying number of resources spanning more than 1
contiguous symbol and changing dynamically every bTTI.
[0180] The number of symbols and resources for each multicast
NR-PDCCH may be indicated via a NR-PCFICH, as shown in the example
of FIG. 20. A NR-PCFICH may be configured for each broadcast
NR-PDCCH, where its resources are predefined in the 3GPP standards
with respect to the band slice size and location. The resources for
NR-PCFICH may be limited to the leading symbol of the
multicast-NR-PDCCH region and be multiplexed with those of the
corresponding multicast-NR-PDCCH so that the latency to process
data is minimized.
[0181] FIG. 21 shows an example configuration of a band slice in a
bTTI where the number of symbols for the first multicast-NR-PDCCH
is configured by the PDNICH and the remaining by NR-PCFICH. The
PDNICH, if present, may indicate the number of symbols for the
first multicast-NR-PDCCH region of the bTTI through the field
numControlSymbols, as shown in an example configuration of the
K.sup.th band slice in Table 9. Subsequent multicast-NR-PDCCH
regions in the bTTI carry a NR-PCFICH.
TABLE-US-00009 TABLE 9 PDNICH field indicating number of symbols
for first multicast-NR-PDCCH for band slice K bandsliceConfig-k
cpConfig-k = 2.35 (.mu.s) subcarrierSpacing = 30 (KHz) guardBandTop
= 90 (KHz) guardBandBottom = 90 (KHz) numResources = 120 (30 KHz
subcarriers) startResource = 7.5 (MHz from the center of band)
numControlSymbols = 1
[0182] Resources for the multicast-NR-PDCCH, other than the first
one, may be set up by system information reserving locations for
each band slice within the TTI for each numerology. MAC CE may then
semi-statically update the set up. Alternatively, future resources
for the multicast-NR-PDCCH may be set up by a prior occurrence of
the multicast-NR-PDCCH that reserves the resources for the
subsequent multicast-NR-PDCCH within a TTI for a given
numerology.
[0183] For some network slices such as mMTC, in order to conserve
battery power, the DL control information may occur only in
specific multicast-NR-PDCCH regions, for example, in the
multicast-NR-PDCCH occurring at the start of the TTI.
[0184] Some types of control information may be split into multiple
regions. For example, the multicast-NR-PDCCH may assign a DL grant
to a UE in a bTTI but additional control information may be
provided by a resources referred to as "pre-coded-NR-PDCCH" and
located within the DL grant. In other words, the pre-coded-NR-PDCCH
is self-contained within the subframe of the DL grant.
[0185] For example, the multicast-NR-PDCCH may provide the DL grant
location and DMRS resource information for the pre-coded-NR-PDCCH
of that grant. Once the terminal decodes this multicast-NR-PDCCH,
it may determine the location of its pre-coded-NR-PDCCH and decodes
it to determine the transmission mode, DMRS information for the
layers, antenna configuration, etc. The solution enables minimizing
the amount of resources allotted for multicast-NR-PDCCH and thereby
reduces the latency. It also allows a portion of the DCI to be
pre-coded, thereby providing higher SNR or alternatively requiring
fewer resources for the DCI.
[0186] FIG. 22 shows an example configuration indicating the
pre-coded-NR-PDCCH in a self-contained manner within the DL grant
to the UE. FIG. 23 shows an example method involved in decoding the
downlink control information in two steps: decoding
multicast-NR-PDCCH from the respective band slice, and then
decoding the pre-coded-NR-PDCCH following which the UE acts on the
grant.
[0187] The DMRS may be used for one or more layers of the DL data
and be shared by the pre-coded-NR-PDCCH to minimize the reference
signal overhead. A pre-coded-NR-PDCCH may be located in the early
symbols of the subframe, and sufficient number of DMRS resources
may be located in the early symbols of the subframe, so that the
pre-coded-NR-PDCCH may be decoded with minimal latency. FIG. 22
shows NR-RS resources allocated to a UE and shared to decode the
pre-coded-NR-PDCCH.
[0188] In order to address the problems associated with the large
latency of transmission mode switching in the current 3GPP system,
the following example mechanisms to enable dynamic transmission
mode switching, while not increasing the number of blind decoding
attempts, are proposed.
[0189] A new downlink control signaling, Physical Slot Format
Indicator Channel (PSFICH), may be used to inform the UE about
necessary information of the current slot, such as the length of
the slot, the symbols for downlink transmission region, and the
symbols for uplink transmission region. The PSFICH may be
transmitted at the first symbol of each slot. The PSFICH may also
be encoded in low coding rate and transmitted in transmit diversity
mode to improve reliability.
[0190] A two-tier NR PDCCH may be used to support dynamic
transmission mode switching and reduce the blind decoding attempts.
The first tier NR PDCCH may be transmitted in the downlink control
region, and its search space could be common and/or UE-specific.
The first tier NR PDCCH may have a unified NR DCI format, which
does not depend on the transmission mode. The first tier NR PDCCH
may also contain the necessary information for the second tier NR
PDCCH blind decoding, such as the index of the NR DCI format used
for the second tier NR PDCCH and the search space indicator used to
configure the second tier NR PDCCH search space. The second tier NR
PDCCH may contain all of the required information for the scheduled
downlink transmission. The second tier NR PDCCH may be transmitted
in the control region or the data region. The second tier NR PDCCH
search space may be UE-specific and may be determined by the search
space indicator in the first tier NR PDCCH, the current slot
structure, and/or the UE ID. For different transmission modes, the
second tier NR PDCCH may have different DCI formats, which are
signaled in the first tier NR PDCCH. The transmit diversity scheme
or beam based diversity scheme may be applied to signals in the
control region, and the NR PDCCH located in the data region may be
configured with the same transmission mode as the data channel.
[0191] Another option to signal the index of the second tier NR DCI
format, which may be through the MAC CE. In this case, the first
tier NR PDCCH may not be necessary.
[0192] A further option is NR transmission modes where the number
of which is much less the number of transmission modes in the
current LTE.
[0193] Another option is to use various NR DCI formats for
different NR transmission modes to support the two-tier NR
PDCCH.
[0194] A new channel Physical Slot Format Indicator Channel
(PSFICH) is defined which is used to indicate the self-contained
structure of the current slot. There is one and only one PSFICH in
each cell. The PSFICH indicates the instantaneous sizes of the
downlink region and the uplink region in terms of the number of
OFDM symbols. If the slot size is dynamic, it should also signal
the size of the current slot. For example, the following
information can be transmitted in the PSFICH: size of the downlink
region (e.g., 4 bits for the number of OFDM symbols in the downlink
region); size of the uplink region (e.g., 4 bits for the number of
OFDM symbols in the uplink region; and size of the current slot
(e.g., 4 bits for the number of OFDM symbols in the current
slot.)
[0195] Example PSFICHs with dynamic and static slot sizes are shown
in FIG. 24, while their PSFICHs are summarized in Table 10.
TABLE-US-00010 TABLE 10 PSFICHs with Dynamic and Static Slot Sizes
Field Name PSFICH A1 PSFICH A2 PSFICH B Size of the downlink 9 4 8
region Size of the uplink 4 2 5 region Size of the current 14 7
Static (14) slot
[0196] If the number of symbols in the guard region is static or
semi-static, it may not be necessary to signal the size of the
uplink region directly, which can be calculated from the sizes of
the current slot, the downlink region and the guard region.
[0197] The PSFICH may be transmitted in single antenna or transmit
diversity mode. The PSFICH contains N information bits, where N
depends on whether the sizes of the current slot and the uplink
region are explicitly signaled. It is first coded by a channel code
with a rate of 1/R, where the rate 1/R should be low to improve the
reliability. The RN coded bits are scrambled with a scrambling
code, depending on TRP ID, to randomize the interference, and then
are modulated and mapped to resource elements RE. These REs should
be well spread in frequency and cover the full downlink
bandwidth.
[0198] In an exemplary mapping, coded bits are modulated by
2.sup.d-QAM, and the i-th coded symbol group containing S symbols
is mapped to the k-th RE group with S REs, where
k = k ' + i * dS * M RN , ##EQU00001##
M is the total number of RE groups in the downlink bandwidth,
k'=
( N sc RB 2 ) * ( N ID TRP .times. .times. mod .times. .times. 2
.times. N RB DL ) , ##EQU00002##
where N.sub.ID.sup.TRP is the TRP ID, and N.sub.sc.sup.RB,
N.sub.RB.sup.DL are the number of subcarriers in a RB and the
number of RBs in the downlink channel, respectively.
[0199] Note: When the PSFICH and the PCFICH are transmitted
separately, the RE groups that they are mapped to cannot be
overlapped. The PSFICH should be mapped to resource elements first,
and the mapping of the PCFICH should avoid the REs occupied by the
PSFICH.
[0200] The PSFICH may be combined with PCFICH to form a new
downlink control channel. The PSFICH may also carry information of
the size of the downlink control region. For example, the size of
the downlink control region may also be transmitted in the PSFICH,
including two bits for the number of OFDM symbols at the beginning
of the downlink region, where the size of the downlink control
region should be less than or equal to the size of downlink
region.
[0201] Example slot structures indicated by PSFICH with Control
Format Indicator (CFI) are shown in FIG. 25, while their PSFICHs
are summarized in Table 11.
TABLE-US-00011 TABLE 11 PSFICHs with Control Format Indicator Field
Name PSFICH A1 PSFICH A2 PSFICH B Size of the downlink 9 4 8 region
Size of the DL 3 1 2 control region Size of the uplink 4 2 5 region
Size of the current 14 7 Static (14) slot
[0202] The physical layer procedure for PSFICH with CFI, such as
channel coding, scrambling, modulation, and RE mapping, should
remain the same as described above.
[0203] In this section, a two-tier NR PDCCH channel structure to
support dynamic transmission mode switching in NR is proposed. The
NR DCI formats for the two-tier NR PDCCH can be defined as
follows.
[0204] The NR DCI format 0 may be the only NR DCI format used for
the first tier NR PDCCH. A transmission mode for the data
transmission and a subgroup index n.sub.0 for the second tier
search space may be transmitted by means of the NR DCI format
0.
[0205] The transmission mode for the data transmission may be a
field with a fixed number of bits (e.g., 3 bits) which explicitly
signals to the UE the transmission mode to be used for the downlink
data transmission. Since the one-to-one mapping between the
transmission mode and the second tier NR DCI format, it can be used
to determine the second tier NR DCI format and reduce the UE's
blind decoding attempts. In NR, the transmission modes may include
transmit diversity, open-loop transmission, spatial multiplexing
and beamforming. For example, "000", "001", "010" and "011" may be
used in this field to indicate the transmission modes of transmit
diversity, spatial multiplexing and beamforming, respectively;
and
[0206] The subgroup index n.sub.0 for the second tier search space
may be a field of d bits, (e.g., d=1), which signals to the UE the
subset of the second tier search space to be used in blind
decoding. As a result, the UE can only blindly decode from a subset
of NR PDCCH candidates from its search space, but not from the
entire search space.
[0207] Error detection is provided on the NR DCI transmission
through a Cyclic Redundancy Check (CRC). The entire payload of the
NR DCI format 0 contains the information bits and the CRC parity
bits. The CRC parity bits are calculated based on the information
bits, which contains the two fields defined above, and then are
scrambled with the corresponding RNTI so that the UE can confirm
whether the DCI is intended to send to itself.
[0208] As an alternative, to reduce the overhead of the first tier
NR PDCCH, it could be transmitted in a group based approach. The
first tier NR DCIs for multiple UEs can be combined to a single
message and transmitted together. The NR node may group at most K
active UEs together and assign them a group ID, where K is
predefined in the standard specification. The NR DCI format 0
messages for UEs in the group are attached to form a single
message. The CRC parity bits are calculated based on the entire
payload of the combined message, and then scrambled with the group
ID. The group ID is configured to the UE through RRC signaling, and
the location of UE's individual message in the combined message
could be predefined or signaled to the UE through RRC signaling.
After receiving the signal, the UE can perform CRC, and if
successful, the UE may obtain its first tier NR PDCCH message from
its assigned location.
[0209] Another method of reducing the overhead is to set an
expiration time for a first tier NR PDCCH message. If the message
is the same from the previous slots and it is not expired, the NR
node has no need to resend the same message. When the UE receives a
new first tier NR PDCCH message, it may apply the same
configuration for the transmission mode and the second tier search
space in the following slot, until a new first tier NR PDCCH comes
or the current one expires. The expiration time may be predefined
in the standard specification or configured by higher layer
signaling.
[0210] The second tier NR DCI formats are designed for different
transmission modes. In NR, the transmission modes may include
transmit diversity, open-loop transmission, spatial multiplexing,
and beamforming. Only one NR DCI format may be needed for each of
these transmission modes in NR. The following information may be
transmitted by all NR DCI formats for the second tier NR PDCCH.
[0211] A carrier indicator may be used for cross carrier
scheduling, which is optional and configured by RRC signaling. The
basic information of other carriers, such as numerology, is also
signaled through higher layer signaling. For example, a resource
allocation may carry the resource allocation assignment. If there
are different resource allocation methods in one NR DCI format,
then a resource allocation flag field may be required to indicate
which method is selected.
[0212] An alternate option is to configure the resource allocation
method through higher layer signaling; a modulation and coding
scheme (for each transmission block); a new data indicator (for
each transmission block); a redundancy version (for each
transmission block); a HARQ process number; a Downlink Assignment
Index; transmission power control information; and SRS request
(only be present for TDD operation).
[0213] In the NR DCI format for open-loop transmission, pre-coding
matrix information may also be required, including information such
as codebook index and PMI. The antenna ports for open-loop
transmission could be predefined in the standards or configured by
higher layer signaling.
[0214] In the NR DCI format for spatial multiplexing transmission,
the number of layers and antenna port indices may also be required.
This information may be signaled to the UE implicitly or
explicitly. For implicit signaling, a set of limited configurations
of these parameters may be pre-defined in the standard
specification or configured by higher layer signaling. In the NR
DCI format, only the index of the selected configuration is
required.
[0215] In the NR DCI format for beamforming transmission, antenna
port index information may be required. The antenna ports are
different from those for spatial multiplexing. Each antenna port
for beamforming transmission represents a pair of transmit and
receive beams, which are found in beam training. The maximum number
of transmit and receive beam pairs is configured by higher layer
signaling. The antenna port index could be signaled to the UE
implicitly or explicitly. For implicit signaling, a set of limited
configurations of these parameters could be predefined in the
standard specification or configured by higher layer signaling. In
the NR DCI format, only the index of the selected configurations is
signaled.
[0216] For transmit diversity transmission, no more information is
required in its NR DCI format. The details for the transmit
diversity are discussed further below.
[0217] The second tier NR DCI formats have the same error detection
and scrambling procedure as the first tier NR DCI format, so that
the UE could decide whether the NR DCI is intended to send to
itself.
[0218] The first tier NR PDCCH may be transmitted in the downlink
control region, and may be mapped to the resources in either common
search spaces or UE-specific search spaces. The control region
consists of a set of CCEs, with indices from 0 to N.sub.CCE,k-1,
where N.sub.CCE,k is the total number of CCEs in the control region
of slot k.
[0219] The common search space is defined as a set of NR PDCCH
candidates which could be used to transmit system control messages
as well as individual control messages. To achieve the high
reliability requirement for the system messages, the common search
spaces may be defined with high aggregation levels. For example,
the CCEs corresponding to m-th NR PDCCH candidate in the common
search space with aggregation level l may be defined as l(m mod
.left brkt-bot.N.sub.CCE,k/l.right brkt-bot.)+i, where i=0, . . . ,
l-1, m=0, . . . M.sub.0.sup.(l)-1, k is the slot number and
M.sub.0.sup.(l) is the number of NR PDCCH candidates the search
space.
[0220] The UE-specific search space may be different for each UE
for efficient utilization of the resources in the system. To
exploit any possible frequency diversity and randomize the
interference, the UE-specific search space may be designed to be
time-variant and to spread across the full bandwidth. The
aggregation levels for the UE-specific search space for the first
tier NR PDCCH may be designed to meet the required performance even
for the UE at cell edge.
[0221] The second tier NR PDCCH may be transmitted in the downlink
control region or the downlink data region, which is configured by
higher layer signaling, and may be mapped to the resources in the
UE-specific search spaces.
[0222] In the downlink control region, to avoid a situation where
the second tier NR PDCCH candidates are blocked by the first tier
NR PDCCHs, the UE-specific search spaces for the first tier and the
second tier NR PDCCHs should come from different CCE sets A' and
A''. As an example, from the total N.sub.CCE,k CCEs in the downlink
control region, the first N.sub.CCE,k' CCEs form the set of CCEs
for the first tier NR PDCCH (i.e., A'), and the other N.sub.CCE''
(=N.sub.CCE,k-N.sub.CCE,k') CCEs form the set of CCEs for the
second tier NR PDCCH (i.e., A'').
[0223] For example, the search spaces for the first tier and the
second tier NR PDCCHs in the downlink control region may be defined
as follows.
[0224] The CCEs in the set A' corresponding to the m-th NR PDCCH in
the UE-specific search space for the first tier NR PDCCH with
aggregation level l could be defined as l((Y.sub.k,1+m') mod .left
brkt-bot.N'.sub.CCE,k/l.right brkt-bot.)+i, where i=0, . . . , l-1,
k is the slot number, m'=m+M.sub.1.sup.(l)*n.sub.CI where n.sub.CI
is the carrier indicator field value if the UE is configured with
carrier indicator field, else m'=m, where m=0, . . .
M.sub.1.sup.(l)-1 and M.sub.1.sup.(l) is the number of NR PDCCH
candidates the search space. The variable Y.sub.k,1 is defined as
Y.sub.k,1=(l.sub.1,1*Y.sub.k-1,1)mod l.sub.2,1, where Y.sub.-1,1 is
the corresponding RNTI and I.sub.1,1 and I.sub.2,1 are two large
integers, which are coprime.
[0225] The CCEs in the set A'' corresponding to the m-th NR PDCCH
in the n.sub.0-th group in the UE-specific search space for the
second tier NR PDCCH with aggregation level l could be defined
as
l .function. ( ( Y k , 2 + ( n 0 - 1 ) .times. N CCE '' 2 d + m ' )
.times. .times. mod .times. .times. N CCE , k '' .times. / .times.
l ) + i , ##EQU00003##
where i=0, . . . , l-1, k is the slot number, n.sub.0=1, 2, . . . ,
2.sup.d is the group index configured by the first tier NR PDCCH,
m'=m+M.sub.2.sup.(l)*n.sub.CI where n.sub.CI is the carrier
indicator field value if the UE is configured with carrier
indicator field, else m'=m, where m=0, . . . M.sub.2.sup.(l)-1 and
M.sub.2.sup.(l) is the number of NR PDCCH candidates the n.sub.0-th
group of the search space. The variable Y.sub.k,2 is defined as
Y.sub.k,2=(I.sub.1,2*Y.sub.k-1,2)mod I.sub.2,2, where Y.sub.-1,2 is
the corresponding RNTI, I.sub.1,2 and I.sub.2,2 are two large
integers, which are coprime a may be different from I.sub.1,1 and
I.sub.2,1.
[0226] In the downlink data region, higher layer signaling can
configure a UE with one or two sets for NR PDCCH monitoring, one of
which is a localized set and the other a distributed set. Each set
consists of a set of CCEs, with indices from 0 to N.sub.CCE,p,k-1,
where N.sub.CCE,p,k is the total number of CCEs in the set p of
slot k.
[0227] For example, the UE specific search spaces for the second
tier NR PDCCH in the downlink data region may be defined as
follows.
[0228] The CCEs corresponding to the m-th NR PDCCH in the
n.sub.0-th group in the UE-specific search space for the second
tier NR PDCCH with aggregation level l could be defined as
l .function. ( ( Y p , k + m * n CCE , p , k l * M p ( l ) + ( n 0
- 1 ) .times. N CCE , p , k l * M p ( l ) * 2 d + m ' ) .times.
.times. mod .times. .times. N CCE , p , k .times. / .times. l ) + i
, where .times. .times. i = 0 , .times. , l - 1 , ##EQU00004##
k is the slot number, n.sub.0=1, 2, . . . , 2.sup.d is the group
index configured by the first tier NR PDCCH, m'=n.sub.CI if the UE
is configured with carrier indicator field where n.sub.CI is the
carrier indicator field, else m'=0, and
m = 0 , .times. , M p ( l ) - 1 .times. .times. and .times. .times.
M p ( l ) ##EQU00005##
is the number of NR PDCCH candidates in the n.sub.0-th group of the
search space. The variable Y.sub.p,k is defined as
Y p , k = ( I 1 , p ' * Y p , k - 1 ) .times. mod .times. .times. I
2 , p ' ##EQU00006##
where Y.sub.-1,p is the corresponding RNTI, I'.sub.1,p and
I'.sub.2,p are two large integers, which are coprime and may be
different from I.sub.1,1 and I.sub.2,1, I.sub.1,2 and
I.sub.2,2.
[0229] To achieve a high reliability, the NR PDCCH in the control
region may be transmitted by beam based transmit diversity. The
transmit diversity can be based on Space-Frequency Block Code
(SFBC) and Frequency Switch Transmit Diversity (FSTD). FIGS. 6 and
7 illustrate the transmit diversity schemes, which may utilize
multiple beams to provide diversity gain. As shown in FIG. 26, the
SFBC may operate on two beams, while at least four beams may be
needed for FSTD as shown in FIG. 27.
[0230] During beam training, the UE may report the best M beams
according to SINR or other criterion, where M may be configured by
RRC signaling as well as a threshold. In an example case where the
UE has less than M beams with performance meeting the given
threshold, the UE would only report the beams achieving the given
threshold. After beam training, the NR node transmits the actual
number P of formed beam pairs to the UE through RRC signaling,
where P may be less than or equal to M. Antenna ports n.sub.1,
n.sub.2, . . . n.sub.p are defined for each of the P Tx beams. An
exemplary antenna port mapping for the NR PDCCH in the control
region is shown as follows.
[0231] If P.gtoreq.4, FSTD may be applied to the NR PDCCH in the
control region. The signals are mapped to the antenna ports
n.sub.1, n.sub.2, n.sub.3, n.sub.4 for transmission;
[0232] If P=2, 3, SFBC may be applied to the NR PDCCH in the
control region. The signals are mapped to the antenna ports
n.sub.1, n.sub.2 for transmission; and
[0233] If P=1, single beam transmission may be applied to the NR
PDCCH in the control region. The signals are mapped to the antenna
ports n.sub.1 for transmission.
[0234] The above beam training and antenna port mapping procedure
is applicable not only for the NR PDCCH transmission but also for
NR data transmission.
[0235] As an alternative to the two-tier NR PDCCH, this method
supports configuration of potential transmission modes by RRC
signaling and then the transmission mode to be used by the UE at
any given point in time is activated by NR (New Radio) node (e.g.
gNB) command using MAC Control Element (CE) signaling in the MAC
header.
[0236] As an example, the NR node (e.g., gNB) could configure,
through RRC signaling, the UE with the set of potential
transmission modes the NR Node intends to use for the UE. This
could be based on one or more of the following: the UE capability,
the services the UE intend to use or the network assumed the UE
will be using based on the UE service usage history, the operator
policy, the UE subscription profile and expected experienced user
experience (e.g. platinum, gold, silver or bronze level). An
example of an Antenna configuration information element within an
RRC configuration message is illustrated below.
TABLE-US-00012 Example of antenna information elements -- ASN1START
AntennaInfoCommon ::= SEQUENCE { antennaPortsCount ENUMERATED {an1,
an2, an4, spare1} } AntennaInfoDedicated ::= SEQUENCE {
transmissionModeList TransmissionModeList OPTIONAL
TransmissionModeList ::= SEQUENCE (size
1...maxNumberOfTransmissionMode) of TransmissionMode
TransmissionMode ::= INTEGER (1...axNumberOfTransmissionMode) where
tm1 corrsponds to transmission mode1, tm2 for transmission
mode2,....etc. codebookSubsetRestriction CHOICE { n2TxAntenna-tm3
BIT STRING (SIZE (2)), n4TxAntenna-tm3 BIT STRING (SIZE (4)),
n2TxAntenna-tm4 BIT STRING (SIZE (6)), n4TxAntenna-tm4 BIT STRING
(SIZE (64)), n2TxAntenna-tm5 BIT STRING (SIZE (4)), n4TxAntenna-tm5
BIT STRING (SIZE (16)), n2TxAntenna-tm6 BIT STRING (SIZE (4)),
n4TxAntenna-tm6 BIT STRING (SIZE (16)) } OPTIONAL, -- Cond TM
ue-TransmitAntennaSelection CHOICE{ release NULL, setup ENUMERATED
{closedLoop, openLoop} } } AntennaInfoDedicated-v920 ::= SEQUENCE {
codebookSubsetRestriction-v920 CHOICE { n2TxAntenna-tm8-r9 BIT
STRING (SIZE (6)), n4TxAntenna-tm8-r9 BIT STRING (SIZE (32)) }
OPTIONAL -- Cond TM8 } AntennaInfoDedicated-r10 ::= SEQUENCE {
transmissionMode-r10 ENUMERATED { tm1, tm2, tm3, tm4, tm5, tm6,
tm7, tm8-v920, tm9-v1020, tm10-v1130, spare6, spare5, spare4,
spare3, spare2, spare1}, codebookSubsetRestriction-r10 BIT STRING
OPTIONAL, -- Cond TMX ue-TransmitAntennaSelection CHOICE{ release
NULL, setup ENUMERATED {closedLoop, openLoop} } }
AntennaInfoDedicated-v10i0::= SEQUENCE { maxLayersMIMO-r10
ENUMERATED {twoLayers, fourLayers, eightLayers} OPTIONAL -- Need OR
} AntennaInfoDedicated-v1250 ::= SEQUENCE {
alternativeCodebookEnabledFor4TX-r12 BOOLEAN } -- ASN1STOP
[0237] The NR Nodes may activate or deactivate a transmission mode
using MAC CE. The NR node may perform real-time transmission mode
activation or deactivation decisions based on UE feedback (e.g.,
MAC level feedback) including feedback on UE radio link condition
and channel state information, variation in overall network load
condition, and network operator policies. Information similar to
that defined in NR DCI format 0 may be carried in a new MAC Control
Element as defined below.
[0238] The transmission mode Activation/Deactivation MAC control
element may be defined over a fixed number n of octets. The
transmission MAC CE may be identified by a MAC PDU sub-header with
a Logical Channel Identifier (LCID). Two examples of MAC CE are
illustrated below.
[0239] An Activation/Deactivation MAC control element with one
octet is shown in FIG. 28. It has a fixed size and consists of a
single octet containing seven C-fields and one R-field. An example
of an Activation/Deactivation MAC control element of four octets is
shown in FIG. 29. It has a fixed size and consists of a four octets
containing 31 C-fields and one R-field. The TMi field may be set to
"1" to indicate that the TM shall be activated. The TMi field may
be set to "0" to indicate that the TM shall be deactivated.
[0240] The logical channel ID may be one of the existing reserved
values of LTE downlink logical channels between the range 01011 and
10111 (binary coding). Alternatively the LTE logical channel value
ranges may be extended with new defined values assigned to the
transmission mode MAC CE.
[0241] For this method, the NR PDCCH format should carry the same
information as the second tier NR PDCCH defined above. The physical
layer procedure and search space design could be the same as
well.
[0242] FIG. 30 shows an example procedure for the two-tier NR PDCCH
detection by a UE. The UE first decodes the PSFICH and the PCFICH
to obtain the slot structure and the size of the downlink control
region. According to the slot structure and the size of the
downlink control region, the UE determines the common search spaces
and the UE specific search spaces for the first tier NR PDCCH. The
UE monitors a unified NR DCI format 0 for the first tier NR PDCCH
in its search spaces. The UE blindly decodes every candidate in its
first tier NR PDCCH, and checks the CRS with its ID. If the CRCs
are not successful for any NR PDCCH candidates in the search space,
this implies that the UE is not scheduled in the current slot, and
will not perform the second tier blind decoding. The UE monitors
the corresponding second tier NR DCI format in its second tier
search space. If CRC is successful, the UE can obtain the required
information for the downlink or uplink transmission.
[0243] If the CRC is successful, the UE can obtain the index of the
second tier NR DCI format and an index to determine the second tier
search space from the NR DCI.
[0244] An alternative option of signaling the transmission mode is
through MAC CE.
[0245] Various examples, solutions relating to NR-PDCCH design for
improved reliability are discussed below.
[0246] LTE uses turbo codes to encode data in Uplink (UL) and
Downlink (DL). The mother code consists of 2 parallel concatenated
recursive convolutional encoders providing a code rate of 1/3. In
New Radio (NR), low rate codes are being considered for encoding
the data and control for both Ultra-Reliable and Low Latency
Communications (URLLC) and massive Machine Type Communication
(mMTC) applications. For URLLC, low rate codes provide higher
reliability from improved coding gain. mMTC gains from low rate
coding because the need for retransmissions is
lowered--consequently power is conserved.
[0247] It is expected that NR will target much lower BLER for data
than LTE (e.g., BLER of 10 or less). Currently LTE's operating
point is typically 10-1 for a single transmission although it is a
proprietary configuration in the eNB. The target BLER for NR is
expected to be achieved through more robust low rate codes and
possibly retransmissions.
[0248] 3GPP TR 38.913 defines scenarios and requirements for next
generation access technologies. According to this requirement, for
URLLC the target for user plane latency should be 0.5 ms for UL,
and 0.5 ms for DL. This implies that the BLER has to be achieved
within these latency constraints.
[0249] For NR, it has been suggested that code rates between 1/3
and 1/15 are of interest. Packet sizes as small as 20 Bytes are
being considered. These codes may be applied both for data and
control channels in the UL and DL.
[0250] LTE supports a minimum packet size of 40 bits; if the
Transport Block (TB) is smaller than 40 bits, it is zero-padded to
have 40 bits. A Cyclic Redundancy Check (CRC) is applied to the TB.
At the receiver, if this CRC check fails, a Non-acknowledgement
(NACK) is sent and a retransmission follows.
[0251] Transport block sizes greater than 6144 are split into
multiple code blocks not exceeding 6144 bits. A CRC is applied to
each code segment. Even if a single CB is in error, HARQ
retransmissions consist of the entire transport block. FIG. 31
shows an example of the data processing chain in LTE UL.
[0252] It has been agreed in NR that a subframe may contain a fixed
number of symbols. It may support multiple control regions and one
or more data transmissions. Multiple numerologies may be
multiplexed in a subframe through TDM/FDM.
[0253] 3GPP TS 36.300 summarizes the different characteristics of
MAC and RRC control are as shown in Table 12 below.
TABLE-US-00013 TABLE 12 Summary of the difference between MAC and
RRC control Control MAC control RRC control entity MAC RRC
Signaling PDCCH MAC control RRC message PDU Signaling ~10.sup.-2
(no ~10.sup.-3 (after ~10.sup.-6 (after reliability retransmission)
HARQ) ARQ) Control delay Very short Short Longer Extensibility None
or very Limited High limited Security No integrity No integrity
Integrity protection protection protection No ciphering No
ciphering Ciphering
[0254] A difference between MAC and RRC control lies in the
signaling reliability. Due to the signaling reliability, signaling
involving state transitions and radio bearer configurations should
be performed by RRC. Basically, signaling performed by RRC in UTRA
should also be performed by RRC also for E-UTRA.
[0255] The MAC sublayer is responsible for the
multiplexing/de-multiplexing of MAC Service Data Units (SDUs)
belonging to one or more logical channels into/from transport
blocks (TB) delivered to/from the physical layer on transport
channels. A MAC Protocol Data Unit (PDU) consists of a MAC header,
zero or more MAC SDUs, zero, or more MAC control elements, and
optionally padding; as shown in FIG. 32.
[0256] In one example, the control information for different use
cases is multiplexed within a common set of resources. For example,
eMBB and URLL may both operate using the same subcarrier spacing.
Accordingly, both use cases may have their NR-DCI (transmitted on
NR-PDCCHs) mapped into a common control region in the subframe. In
some cases, the URLL or eMBB UE blindly decodes the common control
region to its respective NR-PDCCH(s). FIG. 33 shows an example
where NR-PDCCH from URLLC and eMBB are multiplexed within a common
control search space of a subframe. The remaining symbols of the
subframe are multiplexed between URLLC and eMBB data.
[0257] In LTE, different aggregation levels were used to provide
different code rates for the PDCCHs. The LTE eNB typically
determines the aggregation level for a PDCCH based on the weakest
SNR of a UE for whom the information is targeted, especially for
multicast DCI. However, in NR, the reliability requirements of the
NR-PDCCHs can be very different. For example, URLL may require
error rates lower than 10.sup.-4 while eMBB may operate at
10.sup.-3. Here, the use case may be an additional driver in
determining the coding rate of a particular NR-PDCCH.
[0258] In another example, the NR-PDCCHs of use cases with more
stringent latency requirements be mapped to resources in the
leading symbols within the subframe. FIG. 34 shows an example where
the NR-PDCCHs of the URLL use case are mapped beginning with the
1st symbol of the subframe. The NR-PDCCHs of the eMBB use case are
mapped to available resources in the subsequent symbols.
[0259] In an example, data for the latency constrained use cases is
mapped to leading symbols or the earliest symbols occurring in a
transmission interval. For example, as seen in FIG. 34, the data
for URLL case is mapped to the leading resources in the
transmission interval to reduce latency. FIG. 35 shows another
example where the resources may be reserved for carrying data in
the leading symbols of a subframe to provide minimal latency to
data. Here, the leading symbols consist of resources preassigned to
the common search space and resources reserved for data. The URLL
data is carried in the leading symbols while eMBB data is carried
in the following symbols. The NR-PDCCH for the URLL may be assigned
in the leading symbols of the control region.
[0260] In order to support this, by way of one example, we propose
that NR-DCI have the ability to configure the resources for the
multiplexed users in terms of PRBs in each symbol. For example, in
FIG. 36, three users are configured, 2 of which are URLL and 1 is
eMBB. The NR-DCI for these grants should configure symbol #1 for
UE1, #2 for UE2 and a part of symbol #2 and symbols #3 through 6
for UE3. One PRB may be smallest allocation of resources; so the
NR-DCI would configure the PRBs per symbols for the UEs.
[0261] In an example, the NR-PDCCHs carrying DCI for multicast
message may be transmitted using lower coding rates based on the
reliability requirements for the most stringent use case among
several use cases signaled in this DCI. For example, multicast
NR-DCIs such as those for paging and power control may target both
URLL and eMBB and should be coded with lower code rates to support
the reliability requirements of URLL.
[0262] In another example, a common mother code may be used for
some, for instance all, use cases. URLLs may use lower code rates
to achieve additional reliability while eMBB may use higher code
rates. An example way to achieve this is to enable appropriate rate
matching to allow large aggregation levels for URLL. An example way
to achieve these greater aggregation levels is to transmit the
multiple redundancy versions RV.sub.0 . . . RV.sub.n (like the
transport blocks/code blocks of PDSCH or PUSCH in LTE), where
n.gtoreq.1 and RV.sub.i is in the set of aggregation levels for
eMBB. So the NR-Node shall transmit several redundancy versions of
an NR-PDCCH to achieve the target code rate/aggregation level for
URLL but at least one of the versions can be decoded by eMBB with
acceptable error rate. These redundancy versions may be transmitted
in one of the following ways.
[0263] The different redundancy versions can be distinctly
identified in frequency. FIG. 37 shows an example where two
redundancy versions RV.sub.0 and RV.sub.1 are supported for the low
rate NR-DCIs. RV.sub.0 and RV.sub.1 of a URLL's NR-PDCCH occur in
symbol #0 but can be distinguished separately by a URLL UE. An
example advantage of this scheme is that some devices that do not
support URLL modes do not require low rate code decoders in their
hardware. Effectively, the eMBB receiver can be unaware of the
lower code rates as long as at least one of the RVs is within the
set of code rates supported by eMBB use cases.
[0264] For example, an eMBB device that does not require the
reliability levels of URLL operation may not require low code rate
decoders. Assuming that the NR-PDCCH is a multicast message, such
an eMBB device decodes RV.sub.0 alone successfully with acceptable
reliability. It may separately decode RV.sub.1. If successful it
ignores the repeated DCI; if it fails it ignores the DCI. On the
other hand, the URLL UE jointly decodes RV.sub.0 and RV.sub.1 and
achieves higher reliability without sacrificing latency.
[0265] FIG. 38 shows the URLL UE's procedure for blindly decoding
the NR-PDCCH. Here, 2 redundancy versions are assumed for the low
rate NR-DCI codes. The URLL UE jointly decodes them in its blind
search.
[0266] FIG. 39 shows the URLL UE's procedure for blindly decoding
the NR-PDCCH. The eMBB UE ma ignore the low code rates and blindly
decode the hypotheses, assuming eMBB code rates and aggregation
levels.
[0267] Referring now to FIG. 40, the different redundancy versions
may transmitted in different symbols. FIG. 40 shows an example
where the NR-PDCCH for URLL use case is segmented into RV.sub.0 and
RV.sub.1 transmissions on symbols 1 and 2 of a subframe and
multiplexed with the NR-PDCCHs for eMBB. An advantage of this
scheme is that latency constrained devices with good SINR can
successfully decode RV0 with acceptable reliability and immediately
respond to the NR-DCI. Devices with poor SINR wait for the 2.sup.nd
symbol and jointly decode RV.sub.0 and RV.sub.1 before acting on
their grant. Through this scheme a vast majority of the UEs can be
provided high performance with low latency. In some cases, only
cell edge UEs are likely to suffer from worse latency. Note that
with this scheme, UEs that might not need to support low rate
NR-DCI code rates (for example eMBB UEs are not required to have
low rate decoders in their hardware).
[0268] FIG. 41 shows the URLL UE's procedure to obtain its NR-DCI.
In the 1st step, the UE decodes all the RV0s blindly to search its
NR-DCI. In the 2nd step it decodes RV0 and RV1 jointly. This is
especially a good procedure to follow if the UE detects sufficient
SINR operation conditions because the likelihood of detection is
very high in the 1st step. Consequently the latency in FIG. 41
shows the URLL UE's procedure to obtain its NR-DCI. In the 1st
step, the UE decodes all the RV0s blindly to search its NR-DCI. In
the 2nd step it decodes RV0 and RV1 jointly. This may be especially
a good procedure to follow if the UE detects sufficient SINR
operation conditions because the likelihood of detection is very
high in the 1st step. Consequently the latency in processing the
NR-DCI can be minimized.
[0269] FIG. 42 shows an alternative procedure for the URLL UE to
decode it NR-DCI. Here, the UE may decode RV.sub.0 for an NR-DCI.
If it fails, it decodes RV.sub.0 and RV.sub.1 together. Then it
starts decoding the RV.sub.0 of the next NR-DCI hypothesis. Thus,
it iterates through all the redundancy versions for an NR-PDCCH
before attempting to decode the next NR-PDCCH. FIG. 43 shows an
example of a low code rate NR-PDCCH split into RVs, using both time
and frequency resources.
[0270] In another example, both time and frequency demarcation is
incorporated. FIG. 44 shows an example where the RV.sub.0 and
RV.sub.1 occur in different symbols and different frequency
locations. For these schemes transmitting the NR-PDCCH in multiple
redundancy versions, we propose that the redundancy version
patterns and resource allocation be predefined in the standard
specification. The specific pattern used in a transmission may be
configure in a UE semi-statically through RRC signaling and MAC CE
updates.
[0271] Because URLL requires minimal latency and may require to use
the leading symbols within certain transmission intervals, in some
cases, we propose that MAC CEs that require high reliability have
the flexibility to be transmitted in any of the symbols (unlike LTE
where the CBs carrying the MAC CEs are mapped to the leading
symbols). Further, multicast messages, such as paging and system
information on NR-PDSCH, which are meant for both URLL and eMBB,
may be encoded with rates suitable for higher reliability.
[0272] Turning now to dedicated control signaling for use case
requiring increased reliability, the use cases may each have
dedicated resources for control information signaling. For example,
NR-PDCCH of URLL might not be multiplexed with those of eMBB.
[0273] Within a given use case, the NR-PDCCHs may be transmitted in
a common search space and blindly decoded by a UEs to determine its
DCI in a manner similar to decoding the PDCCHs in LTE.
Alternatively the uNR-PDCCHs may be signaled to the UE in
predefined locations in a manner similar to ePDCCH in LTE.
[0274] In both these scenarios the NR-PDCCH may be transmitted
using multiple redundancy versions as described herein. Note that
mMTC devices also benefit from having multiple redundancy versions
for its NR-PDCCHs. For example, a UE can track its SNR and
determine if it should decode one or more redundancy versions for
achieving its target reliability and power consumption. If an mMTC
device determines that it requires only 1 redundancy version, it
only decodes RV.sub.0 thereby conserving power.
[0275] Turning now to other solutions for control signaling,
multiple control signaling regions may be present within a subframe
in the DL as seen in FIG. 44, and each control region may have a
different numerology. Each region may be blindly decoded by a UE to
detect its NR-PDCCH.
[0276] Each control region may provide grants that use resources in
the same symbols as that control region and/or symbols following
the control region as shown in FIG. 46. So a control region cannot
provide a grant in resources preceding the control region in time.
Also the NR-DCI(s) of a later control region may override the
DCI(s) of an earlier control region if the DCIoverRideFlag is set
TRUE, e.g. the MCS value, HARQ scheduling, power control, etc.
[0277] In general, the control region resources, RS and data
resources may be multiplexed into a single symbol as shown in FIG.
45, where the first symbol of the subframe data, control and RSs
are multiplexed together. Note that the subsequent control regions
may puncture a data region. For example, a control region requiring
limited resources may make a URLL grant in a subsequent symbol of
the subframe--here the corresponding control region punctures the
eMBB data as shown in FIG. 47. Note that the URLLC data may
puncture the eMBB data.
[0278] In some cases, the control resources may be dynamically
allocated. The 1st common control region may indicate the presence
and resources of one or more subsequent control regions in the
subframe. We also propose, in accordance with an example
embodiment, that the Nth control region in a subframe may be
indicated by any one of 1 through N-1 control regions. FIG. 48A
shows an example where the 1st control regions indicate information
about the 2nd and 3rd control regions in the subframe. FIG. 48B
shows an example where the 2nd control regions indicate information
about the 3rd control region in the subframe.
[0279] The information indicating the resources for each control
region may include one or more of the following, presented by way
of example and without limitation: number of control regions
configured; numerology of each control region; resources of each
control region (in terms of PRBS/symbols/REs); and beam index of
each control region.
[0280] Alternatively, when control resources are dynamically
allocated, each control region may have a corresponding NR-PCFICH
(similar to the PCFICH in LTE) to indicate the presence and
resources of the control regions. FIG. 49 shows an example where
there are three common search space control regions and each is
configured by its own NR-PCFICH occurring in the same symbol as the
control region. Resources for each NR-PCFICH may be predefined in
the standard specification or indicated through the system
information. The UE may decode the NR-PCFICH--if successful, it
will locate the control region. If no NR-PCFICH and corresponding
control region need to be sent, those resources can carry data.
[0281] A single NR-PCFICH may indicate the resources for multiple
control regions in the subframe. The information in an NR-PCFICH
may include one or more of the following, presented by way of
example and without limitation: number of control regions
configured; numerology of each control region; resources of each
control region (in terms of PRBS/symbols/REs); beam index of each
control region.
[0282] Alternatively, the number of control regions may be
configured semi-statically through system information. The actual
resources and numerology may be configured through NR-PCFICH or the
1st control region as described above.
[0283] In an example, the subsequent control regions may be used
for, for instance only for, carrying specific types of control
information such as DL and UL grants in order to facilitate low
latency applications. Or they may also be configured to carry
NR-PDCCH of certain use cases such as URLLC only so that eMBB
devices may power down during a subframe if it does not find a
grant in the 1st control region. In this example, the subsequent
control regions resources may be predefined or configured
semi-statically or dynamically but only URLLC UEs are required to
decode those control regions. FIG. 50 shows a case where the first
control region may carry NR DCI for both eMBB and URLLC but the
subsequent control regions in the subframe carry only NR-PDCCH for
URLLC UEs.
[0284] In another example, more than 1 UL control region may be
configured in a subframe for example for carrying A/N corresponding
to multiple DL transmissions within a subframe as seen in FIG.
51.
[0285] Multiple DL control regions may provide for multiple UL
transmission resources as shown in FIG. 52.
[0286] Turning now to a Beamformed NR DL Control Channel, an NR DL
control channel can be applied with beamforming. In the initial
access stage, the resource allocation for beam sweeping subframes
can be predetermined with fixed or pre-determined resources for
synchronization channel, beam sweeping RS and primary broadcast
channels. In this way, UE can find the best Tx beams during the Tx
beam sweeping. In case of common NR DL control being needed,
NR-node TX-beam sweeping based transmission can be used for
supporting same coverage with the synchronization channel, beam
sweeping RS and primary broadcast channels. Those common NR DL
control channel search space can be applied with the same beams
used in the beam sweeping for synchronization channel, beam
sweeping RS and primary broadcast channels. Referring to FIG. 53,
it shows the common NR DL control share the same beams setup as DL
beam sweeping RS. The beam sweeping RS can be used for demodulation
of common NR DL control channels.
[0287] In an example, another on-demand beam formed NR DL control
channel (UE-specific) can use the best Tx beams agreed in the
initial access, or the beam refinement stage. By way of example,
the PRACH preamble resource (grids, preamble ID and length) can be
indicated by the detected best Tx beams/beam IDs transmitting from
a single or multiple TR-nodes. If there is transmitting common DL
control then it may provide PRACH resource information for UL PRACH
preamble transmission either with best beam or UL beam sweeping
operation. If there is no common DL control information then UE may
still be able to derive the PRACH resources from the detected beam
information. Since the allocated PRACH resource can be used as an
implicit indication of the best transmit direction beam. A NR-node
can detect the beam formed PRACH preamble indicated by the
pre-allocated PRACH resource. Therefore, NR node can use this
beamforming information for transmitting the random access response
(RAR). Once the UE detect random access response, UE can form the
received beamforming for the reception of the NR DL control
channel. If there is a beam refinement procedure being performed
before the transmission of the (US-specific) NR DL control channel
then the UE can use the refinement beams for NR DL control
reception. An example UE procedure for beam formed DL control
channel is depicted in FIG. 54. In FIG. 54, the dash-line can be
treated as an optional procedure. For example, if there is no
common NR DL control channel available then the UE is still able to
derive the PRACH resources from the beam training stages.
[0288] The 3GPP specification supports transmission of NR-DCI on
multiple beams to improve coverage and reliability. Note that LTE
supported only broadcast of the PDCCH. The beams may sweep through
different spatial locations carrying NR-DCI as shown in FIG.
55.
[0289] In this proposal note that the beams carrying control region
sweep through the space before the UL/DL grant resources are made
available as shown in FIG. 55. Here the DL grant is available N
symbols after the control signaling. The advantage of this scheme
is that latency is less in decoding important control signaling
related to paging, RACH, etc.
[0290] If the UE location is known a-priori, its UE-specific NR-DCI
be transmitted only in a subset of the beams. But if the UE
location is not known to the NR-Node, its NR-DCI may be transmitted
in every beam. This concept in illustrated in FIG. 56 where the
control region is swept by 4 beams covering symbol per beam. A
UE-specific NR-DCI is repeated in all the beams in FIG. 56A but
transmitted only in beams 1 and 2 in FIG. 56B. Note that the NR-DCI
may be located in different subcarriers in different beams.
[0291] Similarly, NR-DCI for common control signaling may be
carried in every beam. The common control search space uses the
same subcarriers in all the beams carrying the control
information--minimizes the overhead to indicate different common
control signaling resources for each beam.
[0292] In another scheme, each beam may carry multiple symbols
including control and data as shown in FIG. 57 where the NR-DCI in
the beam may allocate resources for an UL and/or DL grant in the
same beam. The advantage of this scheme is that the latency between
the control and data is minimal.
[0293] Note that in general, for the schemes described above,
control and data transmission could occur in different beams--for
example, beams for control signaling may be wider than those for
data signaling.
[0294] Certain types of NR-DCI such as common control signals may
be transmitted for beam-wide reception. The NR-DCI can leverage the
beam-RS which is intended for identifying a beam and for
measurements of a beam for also estimating the channel.
[0295] If NR-DCI is transmitted through multiple ports (as in
transmit diversity) a new form of "Control-RS" with appropriate
density may be introduced to aid channel estimation of NR-DCI. This
control-RS would be transmitted for each port that is supported for
NR-DCI transmission. This control-RS may be cell/beam specific and
its location and resources may depend on one or more of cell ID or
beam ID, for example.
[0296] The control-RS may be transmitted to cover channel
estimation for the entire frequency range of the DCI symbols or may
be transmitted in a limited region where DCIs transmitted with
those ports are mapped in frequency.
[0297] FIG. 58 illustrates the beam-RS and control-RS ports. The
control-RS may be defined for more than 1 port. The resources for
multiple ports may be defined with orthogonal covering codes
similar to the OCCs for DMRS ports in LTE.
[0298] Certain types of NR-DCI, especially UE-specific signals may
be pre-coded to improve spatial separation and coverage. For such
use cases, "control-DMRS" may be introduced to aid in channel
estimation.
[0299] FIG. 59 shows a Control DMRS used in UE-specific manner to
decode the NR-DCI.
[0300] The NR-DCI may be transmitted on multiple ports (transmit
diversity or beamforming) and correspondingly the control-DMRS
would be pre-coded similar to the pre-coded NR-DCI and will be
supported on the ports used for data transmission.
[0301] If the data and control are transmitted on the same beam,
they may share the control-RS or control-DMRS resources.
[0302] FIG. 60 shows control DMRS shared between control and data
region if they are pre-coded in the same way.
[0303] The beam-RS, control-RS and control-DMRS can be located in
close proximity to the control region to provide high control
channel reliability.
[0304] The NR-DCI may use a fixed number of control signals or
fixed duration for control signaling in every transmission interval
(which could be a slot or mini-slot or subframe). For such a
design, NR does not need to transmit a PCFICH-like channel as the
control signaling resource is fixed. The control signaling resource
may be indicated through critical system information such as the
MIB or SIB1/SIB2 or may be set to fixed values in the standard
specificatino.
[0305] FIG. 61 shows an example where the number of control signals
is the same in every transmission interval. FIG. 62 shows an
example where the duration of the control signaling is the same for
all numerologies multiplexed in FDM/TDM in the resource grid. So a
transmission interval using 60 KHz subcarrier spacing uses 4
symbols for control signaling whereas a transmission interval
operating at 15 KHz uses 1 symbol for control signaling within that
transmission interval. This solution ensures that the beams sweeps
in every direction for the same period of time.
[0306] Alternatively the specification may specify the number of
symbols for each numerology. The number of symbols may depend on
one or more of: center frequency; bandwidth; and number of beams
supported.
[0307] NR has support for large bandwidths exceeding 80 MHz. If a
UE is required to blindly decode the NR-DCI across the entire
bandwidth it will experience significant latency and battery drain.
So NR must allow transmission of the NR-DCI to a UE in specific
sub-bands--the UE must be configured to have knowledge of the
resources of these sub-bands.
[0308] The UE-specific NR-DCI may be indicated within a limited
number of resources (sub-bands) which are known a priori at the UE.
The sub-bands may be configured semi-statically through RRC and MAC
CE updates. FIG. 63 shows an example where the NR-DCI is carried in
UE-specific sub-bands. The sub-bands may be allocated based on UE
capabilities, i.e. the UE may inform the network about the maximum
bandwidth that it can process at a time. Note that the sub-bands
allocated to a UE need not be contiguous in frequency.
[0309] The search space for common control signaling may carry
NR-DCI such as those for paging, RACH response, etc., and may be
limited to specific sub-bands so that UEs do not have to blindly
decode all the resources in the common control signaling search
space.
[0310] The common control signaling search space may be partitioned
into multiple search spaces and UE may be assigned to search for
the common NR-DCI only within a subset of those search spaces. FIG.
64 shows an example where the common signaling search space is
partitioned into 4 search spaces and a UE is configured to search
for its common NR-DCI only within 2 of those spaces.
[0311] Similar to the solution described above for sub-band
operation for UE-specific and common NR-DCI, Physical DL shared
channel (NR-PDSCH) carrying the data may also be restricted to
sub-bands. This limits the number of times the UE's front end has
to be re-tuned to a new frequency for reception. The sub-bands for
NR-PDSCH may be semi-statically configured through RRC and MAC CE
updates. FIG. 65 shows an example where the NR-PDSCH for a UE is
transmitted over preconfigured sub-bands; so the UE is tuned to
perform reception of data only over the range of frequencies
covering the sub-bands.
[0312] The 3rd Generation Partnership Project (3GPP) develops
technical standards for cellular telecommunications network
technologies, including radio access, the core transport network,
and service capabilities--including work on codecs, security, and
quality of service. Recent radio access technology (RAT) standards
include WCDMA (commonly referred as 3G), LTE (commonly referred as
4G), and LTE-Advanced standards. 3GPP has begun working on the
standardization of next generation cellular technology, called New
Radio (NR), which is also referred to as "5G". 3GPP NR standards
development is expected to include the definition of next
generation radio access technology (new RAT), which is expected to
include the provision of new flexible radio access below 6 GHz, and
the provision of new ultra-mobile broadband radio access above 6
GHz. The flexible radio access is expected to consist of a new,
non-backwards compatible radio access in new spectrum below 6 GHz,
and it is expected to include different operating modes that can be
multiplexed together in the same spectrum to address a broad set of
3GPP NR use cases with diverging requirements. The ultra-mobile
broadband is expected to include cmWave and mmWave spectrum that
will provide the opportunity for ultra-mobile broadband access for,
e.g., indoor applications and hotspots. In particular, the
ultra-mobile broadband is expected to share a common design
framework with the flexible radio access below 6 GHz, with cmWave
and mmWave specific design optimizations.
[0313] 3GPP has identified a variety of use cases that NR is
expected to support, resulting in a wide variety of user experience
requirements for data rate, latency, and mobility. The use cases
include the following general categories: enhanced mobile broadband
(e.g., broadband access in dense areas, indoor ultra-high broadband
access, broadband access in a crowd, 50+ Mbps everywhere, ultra-low
cost broadband access, mobile broadband in vehicles), critical
communications, massive machine type communications, network
operation (e.g., network slicing, routing, migration and
interworking, energy savings), and enhanced vehicle-to-everything
(eV2X) communications. Specific service and applications in these
categories include, e.g., monitoring and sensor networks, device
remote controlling, bi-directional remote controlling, personal
cloud computing, video streaming, wireless cloud-based office,
first responder connectivity, automotive ecall, disaster alerts,
real-time gaming, multi-person video calls, autonomous driving,
augmented reality, tactile internet, and virtual reality to name a
few. All of these use cases and others are contemplated herein.
[0314] FIG. 66 illustrates one embodiment of an example
communications system 100 in which the methods and apparatuses
described and claimed herein may be embodied. As shown, the example
communications system 100 may include wireless transmit/receive
units (WTRUs) 102a, 102b, 102c, and/or 102d (which generally or
collectively may be referred to as WTRU 102), a radio access
network (RAN) 103/104/105/103b/104b/105b, a core network
106/107/109, a public switched telephone network (PSTN) 108, the
Internet 110, and other networks 112, though it will be appreciated
that the disclosed embodiments contemplate any number of WTRUs,
base stations, networks, and/or network elements. Each of the WTRUs
102a, 102b, 102c, 102d, 102e may be any type of apparatus or device
configured to operate and/or communicate in a wireless environment.
Although each WTRU 102a, 102b, 102c, 102d, 102e is depicted in
FIGS. 66-70 as a hand-held wireless communications apparatus, it is
understood that with the wide variety of use cases contemplated for
5G wireless communications, each WTRU may comprise or be embodied
in any type of apparatus or device configured to transmit and/or
receive wireless signals, including, by way of example only, user
equipment (UE), a mobile station, a fixed or mobile subscriber
unit, a pager, a cellular telephone, a personal digital assistant
(PDA), a smartphone, a laptop, a tablet, a netbook, a notebook
computer, a personal computer, a wireless sensor, consumer
electronics, a wearable device such as a smart watch or smart
clothing, a medical or eHealth device, a robot, industrial
equipment, a drone, a vehicle such as a car, truck, train, or
airplane, and the like.
[0315] The communications system 100 may also include a base
station 114a and a base station 114b. Base stations 114a may be any
type of device configured to wirelessly interface with at least one
of the WTRUs 102a, 102b, 102c to facilitate access to one or more
communication networks, such as the core network 106/107/109, the
Internet 110, and/or the other networks 112. Base stations 114b may
be any type of device configured to wiredly and/or wirelessly
interface with at least one of the RRHs (Remote Radio Heads) 118a,
118b and/or TRPs (Transmission and Reception Points) 119a, 119b to
facilitate access to one or more communication networks, such as
the core network 106/107/109, the Internet 110, and/or the other
networks 112. RRHs 118a, 118b may be any type of device configured
to wirelessly interface with at least one of the WTRU 102c, to
facilitate access to one or more communication networks, such as
the core network 106/107/109, the Internet 110, and/or the other
networks 112. TRPs 119a, 119b may be any type of device configured
to wirelessly interface with at least one of the WTRU 102d, to
facilitate access to one or more communication networks, such as
the core network 106/107/109, the Internet 110, and/or the other
networks 112. By way of example, the base stations 114a, 114b may
be a base transceiver station (BTS), a Node-B, an eNode B, a Home
Node B, a Home eNode B, a site controller, an access point (AP), a
wireless router, and the like. While the base stations 114a, 114b
are each depicted as a single element, it will be appreciated that
the base stations 114a, 114b may include any number of
interconnected base stations and/or network elements.
[0316] The base station 114a may be part of the RAN 103/104/105,
which may also include other base stations and/or network elements
(not shown), such as a base station controller (BSC), a radio
network controller (RNC), relay nodes, etc. The base station 114b
may be part of the RAN 103b/104b/105b, which may also include other
base stations and/or network elements (not shown), such as a base
station controller (BSC), a radio network controller (RNC), relay
nodes, etc. The base station 114a may be configured to transmit
and/or receive wireless signals within a particular geographic
region, which may be referred to as a cell (not shown). The base
station 114b may be configured to transmit and/or receive wired
and/or wireless signals within a particular geographic region,
which may be referred to as a cell (not shown). The cell may
further be divided into cell sectors. For example, the cell
associated with the base station 114a may be divided into three
sectors. Thus, in an embodiment, the base station 114a may include
three transceivers, e.g., one for each sector of the cell. In an
embodiment, the base station 114a may employ multiple-input
multiple output (MIMO) technology and, therefore, may utilize
multiple transceivers for each sector of the cell.
[0317] The base stations 114a may communicate with one or more of
the WTRUs 102a, 102b, 102c over an air interface 115/116/117, which
may be any suitable wireless communication link (e.g., radio
frequency (RF), microwave, infrared (IR), ultraviolet (UV), visible
light, cmWave, mmWave, etc.). The air interface 115/116/117 may be
established using any suitable radio access technology (RAT).
[0318] The base stations 114b may communicate with one or more of
the RRHs 118a, 118b and/or TRPs 119a, 119b over a wired or air
interface 115b/116b/117b, which may be any suitable wired (e.g.,
cable, optical fiber, etc.) or wireless communication link (e.g.,
radio frequency (RF), microwave, infrared (IR), ultraviolet (UV),
visible light, cmWave, mmWave, etc.). The air interface
115b/116b/117b may be established using any suitable radio access
technology (RAT).
[0319] The RRHs 118a, 118b and/or TRPs 119a, 119b may communicate
with one or more of the WTRUs 102c, 102d over an air interface
115c/116c/117c, which may be any suitable wireless communication
link (e.g., radio frequency (RF), microwave, infrared (IR),
ultraviolet (UV), visible light, cmWave, mmWave, etc.). The air
interface 115c/116c/117c may be established using any suitable
radio access technology (RAT).
[0320] More specifically, as noted above, the communications system
100 may be a multiple access system and may employ one or more
channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA,
and the like. For example, the base station 114a in the RAN
103/104/105 and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b and
TRPs 119a, 119b in the RAN 103b/104b/105b and the WTRUs 102c, 102d,
may implement a radio technology such as Universal Mobile
Telecommunications System (UMTS) Terrestrial Radio Access (UTRA),
which may establish the air interface 115/116/117 or 115c/116c/117c
respectively using wideband CDMA (WCDMA). WCDMA may include
communication protocols such as High-Speed Packet Access (HSPA)
and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink
Packet Access (HSDPA) and/or High-Speed Uplink Packet Access
(HSUPA).
[0321] In an embodiment, the base station 114a and the WTRUs 102a,
102b, 102c, or RRHs 118a, 118b and TRPs 119a, 119b in the RAN
103b/104b/105b and the WTRUs 102c, 102d, may implement a radio
technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA),
which may establish the air interface 115/116/117 or 115c/116c/117c
respectively using Long Term Evolution (LTE) and/or LTE-Advanced
(LTE-A). In the future, the air interface 115/116/117 may implement
3GPP NR technology.
[0322] In an embodiment, the base station 114a in the RAN
103/104/105 and the WTRUs 102a, 102b, 102c, or RRHs 118a, 118b and
TRPs 119a, 119b in the RAN 103b/104b/105b and the WTRUs 102c, 102d,
may implement radio technologies such as IEEE 802.16 (e.g.,
Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,
CDMA2000 1.times., CDMA2000 EV-DO, Interim Standard 2000 (IS-2000),
Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global
System for Mobile communications (GSM), Enhanced Data rates for GSM
Evolution (EDGE), GSM EDGE (GERAN), and the like.
[0323] The base station 114c in FIG. 66 may be a wireless router,
Home Node B, Home eNode B, or access point, for example, and may
utilize any suitable RAT for facilitating wireless connectivity in
a localized area, such as a place of business, a home, a vehicle, a
campus, and the like. In an embodiment, the base station 114c and
the WTRUs 102e, may implement a radio technology such as IEEE
802.11 to establish a wireless local area network (WLAN). In an
embodiment, the base station 114c and the WTRUs 102d, may implement
a radio technology such as IEEE 802.15 to establish a wireless
personal area network (WPAN). In yet another embodiment, the base
station 114c and the WTRUs 102e, may utilize a cellular-based RAT
(e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, etc.) to establish a
picocell or femtocell. As shown in FIG. 66, the base station 114b
may have a direct connection to the Internet 110. Thus, the base
station 114c may not be required to access the Internet 110 via the
core network 106/107/109.
[0324] The RAN 103/104/105 and/or RAN 103b/104b/105b may be in
communication with the core network 106/107/109, which may be any
type of network configured to provide voice, data, applications,
and/or voice over internet protocol (VoIP) services to one or more
of the WTRUs 102a, 102b, 102c, 102d. For example, the core network
106/107/109 may provide call control, billing services, mobile
location-based services, pre-paid calling, Internet connectivity,
video distribution, etc., and/or perform high-level security
functions, such as user authentication.
[0325] Although not shown in FIG. 66, it will be appreciated that
the RAN 103/104/105 and/or RAN 103b/104b/105b and/or the core
network 106/107/109 may be in direct or indirect communication with
other RANs that employ the same RAT as the RAN 103/104/105 and/or
RAN 103b/104b/105b or a different RAT. For example, in addition to
being connected to the RAN 103/104/105 and/or RAN 103b/104b/105b,
which may be utilizing an E-UTRA radio technology, the core network
106/107/109 may also be in communication with another RAN (not
shown) employing a GSM radio technology.
[0326] The core network 106/107/109 may also serve as a gateway for
the WTRUs 102a, 102b, 102c, 102d, 102e to access the PSTN 108, the
Internet 110, and/or other networks 112. The PSTN 108 may include
circuit-switched telephone networks that provide plain old
telephone service (POTS). The Internet 110 may include a global
system of interconnected computer networks and devices that use
common communication protocols, such as the transmission control
protocol (TCP), user datagram protocol (UDP) and the internet
protocol (IP) in the TCP/IP internet protocol suite. The networks
112 may include wired or wireless communications networks owned
and/or operated by other service providers. For example, the
networks 112 may include another core network connected to one or
more RANs, which may employ the same RAT as the RAN 103/104/105
and/or RAN 103b/104b/105b or a different RAT.
[0327] Some or all of the WTRUs 102a, 102b, 102c, 102d in the
communications system 100 may include multi-mode capabilities,
e.g., the WTRUs 102a, 102b, 102c, 102d, and 102e may include
multiple transceivers for communicating with different wireless
networks over different wireless links. For example, the WTRU 102e
shown in FIG. 66 may be configured to communicate with the base
station 114a, which may employ a cellular-based radio technology,
and with the base station 114c, which may employ an IEEE 802 radio
technology.
[0328] FIG. 67 is a block diagram of an example apparatus or device
configured for wireless communications in accordance with the
embodiments illustrated herein, such as for example, a WTRU 102. As
shown in FIG. 67, the example WTRU 102 may include a processor 118,
a transceiver 120, a transmit/receive element 122, a
speaker/microphone 124, a keypad 126, a display/touchpad/indicators
128, non-removable memory 130, removable memory 132, a power source
134, a global positioning system (GPS) chipset 136, and other
peripherals 138. It will be appreciated that the WTRU 102 may
include any sub-combination of the foregoing elements while
remaining consistent with an embodiment. Also, embodiments
contemplate that the base stations 114a and 114b, and/or the nodes
that base stations 114a and 114b may represent, such as but not
limited to, transceiver station (BTS), a Node-B, a site controller,
an access point (AP), a home node-B, an evolved home node-B
(eNodeB), a home evolved node-B (HeNB), a home evolved node-B
gateway, and proxy nodes, among others, may include some or all of
the elements depicted in FIG. 67 and described herein.
[0329] The processor 118 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Array (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 118 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the WTRU 102 to operate in a wireless environment. The
processor 118 may be coupled to the transceiver 120, which may be
coupled to the transmit/receive element 122. While FIG. 67 depicts
the processor 118 and the transceiver 120 as separate components,
it will be appreciated that the processor 118 and the transceiver
120 may be integrated together in an electronic package or
chip.
[0330] The transmit/receive element 122 may be configured to
transmit signals to, or receive signals from, a base station (e.g.,
the base station 114a) over the air interface 115/116/117. For
example, in an embodiment, the transmit/receive element 122 may be
an antenna configured to transmit and/or receive RF signals.
Although not shown in FIG. 66, it will be appreciated that the RAN
103/104/105 and/or the core network 106/107/109 may be in direct or
indirect communication with other RANs that employ the same RAT as
the RAN 103/104/105 or a different RAT. For example, in addition to
being connected to the RAN 103/104/105, which may be utilizing an
E-UTRA radio technology, the core network 106/107/109 may also be
in communication with another RAN (not shown) employing a GSM radio
technology.
[0331] The core network 106/107/109 may also serve as a gateway for
the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the
Internet 110, and/or other networks 112. The PSTN 108 may include
circuit-switched telephone networks that provide plain old
telephone service (POTS). The Internet 110 may include a global
system of interconnected computer networks and devices that use
common communication protocols, such as the transmission control
protocol (TCP), user datagram protocol (UDP) and the internet
protocol (IP) in the TCP/IP internet protocol suite. The networks
112 may include wired or wireless communications networks owned
and/or operated by other service providers. For example, the
networks 112 may include another core network connected to one or
more RANs, which may employ the same RAT as the RAN 103/104/105 or
a different RAT.
[0332] Some or all of the WTRUs 102a, 102b, 102c, 102d in the
communications system 100 may include multi-mode capabilities,
e.g., the WTRUs 102a, 102b, 102c, and 102d may include multiple
transceivers for communicating with different wireless networks
over different wireless links. For example, the WTRU 102c shown in
FIG. 66 may be configured to communicate with the base station
114a, which may employ a cellular-based radio technology, and with
the base station 114b, which may employ an IEEE 802 radio
technology.
[0333] FIG. 67 is a block diagram of an example apparatus or device
configured for wireless communications in accordance with the
embodiments illustrated herein, such as for example, a WTRU 102. As
shown in FIG. 67, the example WTRU 102 may include a processor 118,
a transceiver 120, a transmit/receive element 122, a
speaker/microphone 124, a keypad 126, a display/touchpad/indicators
128, non-removable memory 130, removable memory 132, a power source
134, a global positioning system (GPS) chipset 136, and other
peripherals 138. It will be appreciated that the WTRU 102 may
include any sub-combination of the foregoing elements while
remaining consistent with an embodiment. Also, embodiments
contemplate that the base stations 114a and 114b, and/or the nodes
that base stations 114a and 114b may represent, such as but not
limited to transceiver station (BTS), a Node-B, a site controller,
an access point (AP), a home node-B, an evolved home node-B
(eNodeB), a home evolved node-B (HeNB), a home evolved node-B
gateway, and proxy nodes, among others, may include some or all of
the elements depicted in FIG. 67 and described herein.
[0334] The processor 118 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Array (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 118 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the WTRU 102 to operate in a wireless environment. The
processor 118 may be coupled to the transceiver 120, which may be
coupled to the transmit/receive element 122. While FIG. 67 depicts
the processor 118 and the transceiver 120 as separate components,
it will be appreciated that the processor 118 and the transceiver
120 may be integrated together in an electronic package or
chip.
[0335] The transmit/receive element 122 may be configured to
transmit signals to, or receive signals from, a base station (e.g.,
the base station 114a) over the air interface 115/116/117. For
example, in an embodiment, the transmit/receive element 122 may be
an antenna configured to transmit and/or receive RF signals. In an
embodiment, the transmit/receive element 122 may be an
emitter/detector configured to transmit and/or receive IR, UV, or
visible light signals, for example. In yet an embodiment, the
transmit/receive element 122 may be configured to transmit and
receive both RF and light signals. It will be appreciated that the
transmit/receive element 122 may be configured to transmit and/or
receive any combination of wireless signals.
[0336] In addition, although the transmit/receive element 122 is
depicted in FIG. 67 as a single element, the WTRU 102 may include
any number of transmit/receive elements 122. More specifically, the
WTRU 102 may employ MIMO technology. Thus, in an embodiment, the
WTRU 102 may include two or more transmit/receive elements 122
(e.g., multiple antennas) for transmitting and receiving wireless
signals over the air interface 115/116/117.
[0337] The transceiver 120 may be configured to modulate the
signals that are to be transmitted by the transmit/receive element
122 and to demodulate the signals that are received by the
transmit/receive element 122. As noted above, the WTRU 102 may have
multi-mode capabilities. Thus, the transceiver 120 may include
multiple transceivers for enabling the WTRU 102 to communicate via
multiple RATs, such as UTRA and IEEE 802.11, for example.
[0338] The processor 118 of the WTRU 102 may be coupled to, and may
receive user input data from, the speaker/microphone 124, the
keypad 126, and/or the display/touchpad/indicators 128 (e.g., a
liquid crystal display (LCD) display unit or organic light-emitting
diode (OLED) display unit). The processor 118 may also output user
data to the speaker/microphone 124, the keypad 126, and/or the
display/touchpad/indicators 128. In addition, the processor 118 may
access information from, and store data in, any type of suitable
memory, such as the non-removable memory 130 and/or the removable
memory 132. The non-removable memory 130 may include random-access
memory (RAM), read-only memory (ROM), a hard disk, or any other
type of memory storage device. The removable memory 132 may include
a subscriber identity module (SIM) card, a memory stick, a secure
digital (SD) memory card, and the like. In an embodiment, the
processor 118 may access information from, and store data in,
memory that is not physically located on the WTRU 102, such as on a
server or a home computer (not shown).
[0339] The processor 118 may receive power from the power source
134, and may be configured to distribute and/or control the power
to the other components in the WTRU 102. The power source 134 may
be any suitable device for powering the WTRU 102. For example, the
power source 134 may include one or more dry cell batteries, solar
cells, fuel cells, and the like.
[0340] The processor 118 may also be coupled to the GPS chipset
136, which may be configured to provide location information (e.g.,
longitude and latitude) regarding the current location of the WTRU
102. In addition to, or in lieu of, the information from the GPS
chipset 136, the WTRU 102 may receive location information over the
air interface 115/116/117 from a base station (e.g., base stations
114a, 114b) and/or determine its location based on the timing of
the signals being received from two or more nearby base stations.
It will be appreciated that the WTRU 102 may acquire location
information by way of any suitable location-determination method
while remaining consistent with an embodiment.
[0341] The processor 118 may further be coupled to other
peripherals 138, which may include one or more software and/or
hardware modules that provide additional features, functionality
and/or wired or wireless connectivity. For example, the peripherals
138 may include various sensors such as an accelerometer,
biometrics (e.g., finger print) sensors, an e-compass, a satellite
transceiver, a digital camera (for photographs or video), a
universal serial bus (USB) port or other interconnect interfaces, a
vibration device, a television transceiver, a hands free headset, a
Bluetooth.RTM. module, a frequency modulated (FM) radio unit, a
digital music player, a media player, a video game player module,
an Internet browser, and the like.
[0342] The WTRU 102 may be embodied in other apparatuses or
devices, such as a sensor, consumer electronics, a wearable device
such as a smart watch or smart clothing, a medical or eHealth
device, a robot, industrial equipment, a drone, a vehicle such as a
car, truck, train, or airplane. The WTRU 102 may connect to other
components, modules, or systems of such apparatuses or devices via
one or more interconnect interfaces, such as an interconnect
interface that may comprise one of the peripherals 138.
[0343] FIG. 68 is a system diagram of the RAN 103 and the core
network 106 according to an embodiment. As noted above, the RAN 103
may employ a UTRA radio technology to communicate with the WTRUs
102a, 102b, and 102c over the air interface 115. The RAN 103 may
also be in communication with the core network 106. As shown in
FIG. 68, the RAN 103 may include Node-Bs 140a, 140b, 140c, which
may each include one or more transceivers for communicating with
the WTRUs 102a, 102b, 102c over the air interface 115. The Node-Bs
140a, 140b, 140c may each be associated with a particular cell (not
shown) within the RAN 103. The RAN 103 may also include RNCs 142a,
142b. It will be appreciated that the RAN 103 may include any
number of Node-Bs and RNCs while remaining consistent with an
embodiment.
[0344] As shown in FIG. 68, the Node-Bs 140a, 140b may be in
communication with the RNC 142a. Additionally, the Node-B 140c may
be in communication with the RNC 142b. The Node-Bs 140a, 140b, 140c
may communicate with the respective RNCs 142a, 142b via an Iub
interface. The RNCs 142a, 142b may be in communication with one
another via an Iur interface. Each of the RNCs 142a, 142b may be
configured to control the respective Node-Bs 140a, 140b, 140c to
which it is connected. In addition, each of the RNCs 142a, 142b may
be configured to carry out or support other functionality, such as
outer loop power control, load control, admission control, packet
scheduling, handover control, macro-diversity, security functions,
data encryption, and the like.
[0345] The core network 106 shown in FIG. 68 may include a media
gateway (MGW) 144, a mobile switching center (MSC) 146, a serving
GPRS support node (SGSN) 148, and/or a gateway GPRS support node
(GGSN) 150. While each of the foregoing elements are depicted as
part of the core network 106, it will be appreciated that any one
of these elements may be owned and/or operated by an entity other
than the core network operator.
[0346] The RNC 142a in the RAN 103 may be connected to the MSC 146
in the core network 106 via an IuCS interface. The MSC 146 may be
connected to the MGW 144. The MSC 146 and the MGW 144 may provide
the WTRUs 102a, 102b, 102c with access to circuit-switched
networks, such as the PSTN 108, to facilitate communications
between the WTRUs 102a, 102b, 102c and traditional land-line
communications devices.
[0347] The RNC 142a in the RAN 103 may also be connected to the
SGSN 148 in the core network 106 via an IuPS interface. The SGSN
148 may be connected to the GGSN 150. The SGSN 148 and the GGSN 150
may provide the WTRUs 102a, 102b, 102c with access to
packet-switched networks, such as the Internet 110, to facilitate
communications between and the WTRUs 102a, 102b, 102c and
IP-enabled devices.
[0348] As noted above, the core network 106 may also be connected
to the networks 112, which may include other wired or wireless
networks that are owned and/or operated by other service
providers.
[0349] FIG. 69 is a system diagram of the RAN 104 and the core
network 107 according to an embodiment. As noted above, the RAN 104
may employ an E-UTRA radio technology to communicate with the WTRUs
102a, 102b, and 102c over the air interface 116. The RAN 104 may
also be in communication with the core network 107.
[0350] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it
will be appreciated that the RAN 104 may include any number of
eNode-Bs while remaining consistent with an embodiment. The
eNode-Bs 160a, 160b, 160c may each include one or more transceivers
for communicating with the WTRUs 102a, 102b, 102c over the air
interface 116. In an embodiment, the eNode-Bs 160a, 160b, 160c may
implement MIMO technology. Thus, the eNode-B 160a, for example, may
use multiple antennas to transmit wireless signals to, and receive
wireless signals from, the WTRU 102a.
[0351] Each of the eNode-Bs 160a, 160b, and 160c may be associated
with a particular cell (not shown) and may be configured to handle
radio resource management decisions, handover decisions, scheduling
of users in the uplink and/or downlink, and the like. As shown in
FIG. 69, the eNode-Bs 160a, 160b, 160c may communicate with one
another over an X2 interface.
[0352] The core network 107 shown in FIG. 69 may include a mobility
management gateway (MME) 162, a serving gateway 164, and a packet
data network (PDN) gateway 166. While each of the foregoing
elements are depicted as part of the core network 107, it will be
appreciated that any one of these elements may be owned and/or
operated by an entity other than the core network operator.
[0353] The MME 162 may be connected to each of the eNode-Bs 160a,
160b, and 160c in the RAN 104 via an S1 interface and may serve as
a control node. For example, the MME 162 may be responsible for
authenticating users of the WTRUs 102a, 102b, 102c, bearer
activation/deactivation, selecting a particular serving gateway
during an initial attach of the WTRUs 102a, 102b, 102c, and the
like. The MME 162 may also provide a control plane function for
switching between the RAN 104 and other RANs (not shown) that
employ other radio technologies, such as GSM or WCDMA.
[0354] The serving gateway 164 may be connected to each of the
eNode-Bs 160a, 160b, and 160c in the RAN 104 via the S1 interface.
The serving gateway 164 may generally route and forward user data
packets to/from the WTRUs 102a, 102b, 102c. The serving gateway 164
may also perform other functions, such as anchoring user planes
during inter-eNode B handovers, triggering paging when downlink
data is available for the WTRUs 102a, 102b, 102c, managing and
storing contexts of the WTRUs 102a, 102b, 102c, and the like.
[0355] The serving gateway 164 may also be connected to the PDN
gateway 166, which may provide the WTRUs 102a, 102b, 102c with
access to packet-switched networks, such as the Internet 110, to
facilitate communications between the WTRUs 102a, 102b, 102c and
IP-enabled devices.
[0356] The core network 107 may facilitate communications with
other networks. For example, the core network 107 may provide the
WTRUs 102a, 102b, 102c with access to circuit-switched networks,
such as the PSTN 108, to facilitate communications between the
WTRUs 102a, 102b, 102c and traditional land-line communications
devices. For example, the core network 107 may include, or may
communicate with, an IP gateway (e.g., an IP multimedia subsystem
(IMS) server) that serves as an interface between the core network
107 and the PSTN 108. In addition, the core network 107 may provide
the WTRUs 102a, 102b, 102c with access to the networks 112, which
may include other wired or wireless networks that are owned and/or
operated by other service providers.
[0357] FIG. 70 is a system diagram of the RAN 105 and the core
network 109 according to an embodiment. The RAN 105 may be an
access service network (ASN) that employs IEEE 802.16 radio
technology to communicate with the WTRUs 102a, 102b, and 102c over
the air interface 117. As will be further discussed below, the
communication links between the different functional entities of
the WTRUs 102a, 102b, 102c, the RAN 105, and the core network 109
may be defined as reference points.
[0358] As shown in FIG. 70, the RAN 105 may include base stations
180a, 180b, 180c, and an ASN gateway 182, though it will be
appreciated that the RAN 105 may include any number of base
stations and ASN gateways while remaining consistent with an
embodiment. The base stations 180a, 180b, 180c may each be
associated with a particular cell in the RAN 105 and may include
one or more transceivers for communicating with the WTRUs 102a,
102b, 102c over the air interface 117. In an embodiment, the base
stations 180a, 180b, 180c may implement MIMO technology. Thus, the
base station 180a, for example, may use multiple antennas to
transmit wireless signals to, and receive wireless signals from,
the WTRU 102a. The base stations 180a, 180b, 180c may also provide
mobility management functions, such as handoff triggering, tunnel
establishment, radio resource management, traffic classification,
quality of service (QoS) policy enforcement, and the like. The ASN
gateway 182 may serve as a traffic aggregation point and may be
responsible for paging, caching of subscriber profiles, routing to
the core network 109, and the like.
[0359] The air interface 117 between the WTRUs 102a, 102b, 102c and
the RAN 105 may be defined as an R1 reference point that implements
the IEEE 802.16 specification. In addition, each of the WTRUs 102a,
102b, and 102c may establish a logical interface (not shown) with
the core network 109. The logical interface between the WTRUs 102a,
102b, 102c and the core network 109 may be defined as an R2
reference point, which may be used for authentication,
authorization, IP host configuration management, and/or mobility
management.
[0360] The communication link between each of the base stations
180a, 180b, and 180c may be defined as an R8 reference point that
includes protocols for facilitating WTRU handovers and the transfer
of data between base stations. The communication link between the
base stations 180a, 180b, 180c and the ASN gateway 182 may be
defined as an R6 reference point. The R6 reference point may
include protocols for facilitating mobility management based on
mobility events associated with each of the WTRUs 102a, 102b,
102c.
[0361] As shown in FIG. 70, the RAN 105 may be connected to the
core network 109. The communication link between the RAN 105 and
the core network 109 may defined as an R3 reference point that
includes protocols for facilitating data transfer and mobility
management capabilities, for example. The core network 109 may
include a mobile IP home agent (MIP-HA) 184, an authentication,
authorization, accounting (AAA) server 186, and a gateway 188.
While each of the foregoing elements are depicted as part of the
core network 109, it will be appreciated that any one of these
elements may be owned and/or operated by an entity other than the
core network operator.
[0362] The MIP-HA may be responsible for IP address management, and
may enable the WTRUs 102a, 102b, and 102c to roam between different
ASNs and/or different core networks. The MIP-HA 184 may provide the
WTRUs 102a, 102b, 102c with access to packet-switched networks,
such as the Internet 110, to facilitate communications between the
WTRUs 102a, 102b, 102c and IP-enabled devices. The AAA server 186
may be responsible for user authentication and for supporting user
services. The gateway 188 may facilitate interworking with other
networks. For example, the gateway 188 may provide the WTRUs 102a,
102b, 102c with access to circuit-switched networks, such as the
PSTN 108, to facilitate communications between the WTRUs 102a,
102b, 102c and traditional land-line communications devices. In
addition, the gateway 188 may provide the WTRUs 102a, 102b, 102c
with access to the networks 112, which may include other wired or
wireless networks that are owned and/or operated by other service
providers.
[0363] Although not shown in FIG. 70, it will be appreciated that
the RAN 105 may be connected to other ASNs and the core network 109
may be connected to other core networks. The communication link
between the RAN 105 the other ASNs may be defined as an R4
reference point, which may include protocols for coordinating the
mobility of the WTRUs 102a, 102b, 102c between the RAN 105 and the
other ASNs. The communication link between the core network 109 and
the other core networks may be defined as an R5 reference, which
may include protocols for facilitating interworking between home
core networks and visited core networks.
[0364] The core network entities described herein and illustrated
in FIGS. 66-70 are identified by the names given to those entities
in certain existing 3GPP specifications, but it is understood that
in the future those entities and functionalities may be identified
by other names and certain entities or functions may be combined in
future specifications published by 3GPP, including future 3GPP NR
specifications. Thus, the particular network entities and
functionalities described and illustrated in FIGS. 66-70 are
provided by way of example only, and it is understood that the
subject matter disclosed and claimed herein may be embodied or
implemented in any similar communication system, whether presently
defined or defined in the future.
[0365] FIG. 71 is a block diagram of an exemplary computing system
90 in which one or more apparatuses of the communications networks
illustrated in FIGS. 66-70 may be embodied, such as certain nodes
or functional entities in the RAN 103/104/105, Core Network
106/107/109, PSTN 108, Internet 110, or Other Networks 112.
Computing system 90 may comprise a computer or server and may be
controlled primarily by computer readable instructions, which may
be in the form of software, wherever, or by whatever means such
software is stored or accessed. Such computer readable instructions
may be executed within a processor 91, to cause computing system 90
to do work. The processor 91 may be a general purpose processor, a
special purpose processor, a conventional processor, a digital
signal processor (DSP), a plurality of microprocessors, one or more
microprocessors in association with a DSP core, a controller, a
microcontroller, Application Specific Integrated Circuits (ASICs),
Field Programmable Gate Array (FPGAs) circuits, any other type of
integrated circuit (IC), a state machine, and the like. The
processor 91 may perform signal coding, data processing, power
control, input/output processing, and/or any other functionality
that enables the computing system 90 to operate in a communications
network. Coprocessor 81 is an optional processor, distinct from
main processor 91, that may perform additional functions or assist
processor 91. Processor 91 and/or coprocessor 81 may receive,
generate, and process data related to the methods and apparatuses
disclosed herein.
[0366] In operation, processor 91 fetches, decodes, and executes
instructions, and transfers information to and from other resources
via the computing system's main data-transfer path, system bus 80.
Such a system bus connects the components in computing system 90
and defines the medium for data exchange. System bus 80 typically
includes data lines for sending data, address lines for sending
addresses, and control lines for sending interrupts and for
operating the system bus. An example of such a system bus 80 is the
PCI (Peripheral Component Interconnect) bus.
[0367] Memories coupled to system bus 80 include random access
memory (RAM) 82 and read only memory (ROM) 93. Such memories
include circuitry that allows information to be stored and
retrieved. ROMs 93 generally contain stored data that cannot easily
be modified. Data stored in RAM 82 can be read or changed by
processor 91 or other hardware devices. Access to RAM 82 and/or ROM
93 may be controlled by memory controller 92. Memory controller 92
may provide an address translation function that translates virtual
addresses into physical addresses as instructions are executed.
Memory controller 92 may also provide a memory protection function
that isolates processes within the system and isolates system
processes from user processes. Thus, a program running in a first
mode can access only memory mapped by its own process virtual
address space; it cannot access memory within another process's
virtual address space unless memory sharing between the processes
has been set up.
[0368] In addition, computing system 90 may contain peripherals
controller 83 responsible for communicating instructions from
processor 91 to peripherals, such as printer 94, keyboard 84, mouse
95, and disk drive 85.
[0369] Display 86, which is controlled by display controller 96, is
used to display visual output generated by computing system 90.
Such visual output may include text, graphics, animated graphics,
and video. The visual output may be provided in the form of a
graphical user interface (GUI). Display 86 may be implemented with
a CRT-based video display, an LCD-based flat-panel display, gas
plasma-based flat-panel display, or a touch-panel. Display
controller 96 includes electronic components required to generate a
video signal that is sent to display 86.
[0370] Further, computing system 90 may contain communication
circuitry, such as for example a network adapter 97, that may be
used to connect computing system 90 to an external communications
network, such as the RAN 103/104/105, Core Network 106/107/109,
PSTN 108, Internet 110, or Other Networks 112 of FIGS. 66-70, to
enable the computing system 90 to communicate with other nodes or
functional entities of those networks. The communication circuitry,
alone or in combination with the processor 91, may be used to
perform the transmitting and receiving steps of certain
apparatuses, nodes, or functional entities described herein.
[0371] It is understood that any or all of the apparatuses,
systems, methods and processes described herein may be embodied in
the form of computer executable instructions (e.g., program code)
stored on a computer-readable storage medium which instructions,
when executed by a processor, such as processors 118 or 91, cause
the processor to perform and/or implement the systems, methods and
processes described herein. Specifically, any of the steps,
operations or functions described herein may be implemented in the
form of such computer executable instructions, executing on the
processor of an apparatus or computing system configured for
wireless and/or wired network communications. Computer readable
storage media include volatile and nonvolatile, removable and
non-removable media implemented in any non-transitory (e.g.,
tangible or physical) method or technology for storage of
information, but such computer readable storage media do not
includes signals. Computer readable storage media include, but are
not limited to, RAM, ROM, EEPROM, flash memory or other memory
technology, CD-ROM, digital versatile disks (DVD) or other optical
disk storage, magnetic cassettes, magnetic tape, magnetic disk
storage or other magnetic storage devices, or any other tangible or
physical medium which can be used to store the desired information
and which can be accessed by a computing system.
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