U.S. patent application number 17/466227 was filed with the patent office on 2021-12-23 for default beam selection based on a subset of coresets.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Arumugam CHENDAMARAI KANNAN, Makesh Pravin JOHN WILSON, Tao LUO, Wooseok NAM, Jing SUN, Srinivas YERRAMALLI, Xiaoxia ZHANG, Yan ZHOU.
Application Number | 20210399787 17/466227 |
Document ID | / |
Family ID | 1000005825986 |
Filed Date | 2021-12-23 |
United States Patent
Application |
20210399787 |
Kind Code |
A1 |
ZHOU; Yan ; et al. |
December 23, 2021 |
DEFAULT BEAM SELECTION BASED ON A SUBSET OF CORESETS
Abstract
In order to overcome problems that a UE may face in determining
a default beam for communication with the base station during a
COT, a method, apparatus, and computer-readable medium are provided
for a base station to indicate to the UE which CORESET(s), QCL
assumptions, UL resources, and/or spatial relationships are
selected for a COT. A UE receives, from a base station, an
indication corresponding to a COT. The indication is for at least
one of a set of CORESETs, a set of QCL assumptions, a set of UL
resources, or a set of spatial relations for determining a default
beam. The UE determines the default beam from the base station for
use during the COT based on the indication. The UE transmits or
receives a transmission using the default beam.
Inventors: |
ZHOU; Yan; (San Diego,
CA) ; LUO; Tao; (San Diego, CA) ; NAM;
Wooseok; (San Diego, CA) ; JOHN WILSON; Makesh
Pravin; (San Diego, CA) ; YERRAMALLI; Srinivas;
(San Diego, CA) ; ZHANG; Xiaoxia; (San Diego,
CA) ; SUN; Jing; (San Diego, CA) ; CHENDAMARAI
KANNAN; Arumugam; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Family ID: |
1000005825986 |
Appl. No.: |
17/466227 |
Filed: |
September 3, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16662766 |
Oct 24, 2019 |
11115110 |
|
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17466227 |
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62780175 |
Dec 14, 2018 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 5/005 20130101;
H04B 7/088 20130101; H04W 72/046 20130101; H04W 72/1205 20130101;
H04W 74/0816 20130101 |
International
Class: |
H04B 7/08 20060101
H04B007/08; H04W 74/08 20060101 H04W074/08; H04W 72/04 20060101
H04W072/04; H04L 5/00 20060101 H04L005/00; H04W 72/12 20060101
H04W072/12 |
Claims
1. A method of wireless communication at a User Equipment (UE),
comprising: receiving, from a base station, an indication
corresponding to a Channel Occupancy Time (COT), wherein the
indication is for at least one of a set of Control Resource Sets
(CORESETs), a set of Quasi co-location (QCL) assumptions, a set of
uplink resources, or a set of spatial relations for determining a
default beam; determining the default beam from the base station
for use during the COT based on the indication; and transmitting or
receiving a transmission using the default beam.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application is a Continuation of U.S. patent
application Ser. No. 16/662,766, entitled "DEFAULT BEAM SELECTION
BASED ON A SUBSET OF CORESET" and filed on Oct. 24, 2019, which
claims the benefit of U.S. Provisional Application Ser. No.
62/780,175, entitled "DEFAULT BEAM SELECTION BASED ON A SUBSET OF
CORESETS" and filed on Dec. 14, 2018, which are expressly
incorporated by reference herein in their entirety.
BACKGROUND
Technical Field
[0002] The present disclosure relates generally to communication
systems, and more particularly, to wireless communication during a
Channel Occupancy Time (COT).
Introduction
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources. Examples of such multiple-access
technologies include code division multiple access (CDMA) systems,
time division multiple access (TDMA) systems, frequency division
multiple access (FDMA) systems, orthogonal frequency division
multiple access (OFDMA) systems, single-carrier frequency division
multiple access (SC-FDMA) systems, and time division synchronous
code division multiple access (TD-SCDMA) systems.
[0004] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example
telecommunication standard is 5G New Radio (NR). 5G NR is part of a
continuous mobile broadband evolution promulgated by Third
Generation Partnership Project (3GPP) to meet new requirements
associated with latency, reliability, security, scalability (e.g.,
with Internet of Things (IoT)), and other requirements. 5G NR
includes services associated with enhanced mobile broadband (eMBB),
massive machine type communications (mMTC), and ultra reliable low
latency communications (URLLC). Some aspects of 5G NR may be based
on the 4G Long Term Evolution (LTE) standard. There exists a need
for further improvements in 5G NR technology. These improvements
may also be applicable to other multi-access technologies and the
telecommunication standards that employ these technologies.
SUMMARY
[0005] The following presents a simplified summary of one or more
aspects in order to provide a basic understanding of such aspects.
This summary is not an extensive overview of all contemplated
aspects, and is intended to neither identify key or critical
elements of all aspects nor delineate the scope of any or all
aspects. Its sole purpose is to present some concepts of one or
more aspects in a simplified form as a prelude to the more detailed
description that is presented later.
[0006] In licensed communication bands, a default UE reception (Rx)
beam may be quasi co-located (QCL) with a lowest Control Resource
Set Identifier (CORESET ID) in the latest monitored slot. However,
communication in unlicensed frequency bands may be limited to a COT
based on performance of a Clear Channel Assessment (CCA). The
shared nature of the medium may lead to use of only a subset of
CORESETs or CORESET QCL assumptions in a given COT. For example, a
base station might only perform or succeed in performing a CCA on
certain beams. Thus, the base station might not use CORESET
resources associated with other beams in the COT. This may lead to
problems for the UE in determining default beams for communication
with the base station during the COT.
[0007] Aspects presented herein improve communication between the
base station and the UE through the base station indicating to the
UE which CORESET(s) or QCL assumptions are selected for a COT. The
UE may use the indication to determine a default beam for the
communication. Similarly, the base station may indicate selected
uplink (UL) resources or spatial relationships for the COT that the
UE may use to determine a default beam.
[0008] In an aspect of the disclosure, a method, a
computer-readable medium, and an apparatus are provided. The
apparatus determines whether an indication corresponding to a COT
is received from a base station, wherein the indication is for at
least one of a set of CORESETs, a set of QCL assumptions, a set of
UL resources, or a set of spatial relations for determining a
default beam. The apparatus determines the default beam from the
base station for use during the COT based on the indication if the
indication is received from the base station. The apparatus then
transmits or receives a transmission using the default beam.
[0009] In another aspect of the disclosure, a method, a
computer-readable medium, and an apparatus are provided. The
apparatus indicates, to a UE at least one of a set of CORESETs, a
set of QCL assumptions, a set of UL resources, or a set of spatial
relations for determining a default beam, the indication being for
use in determining a default beam for use in a COT. The apparatus
then transmits or receives communication with the UE based on the
default beam.
[0010] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a diagram illustrating an example of a wireless
communications system and an access network.
[0012] FIGS. 2A, 2B, 2C, and 2D are diagrams illustrating examples
of a first 5G/NR frame, DL channels within a 5G/NR subframe, a
second 5G/NR frame, and UL channels within a 5G/NR subframe,
respectively.
[0013] FIG. 3 is a diagram illustrating an example of a base
station and user equipment (UE) in an access network.
[0014] FIG. 4 illustrates an example COT.
[0015] FIG. 5 illustrates an example of CORESETs within a COT.
[0016] FIG. 6 illustrates an example communication flow between a
base station and a UE.
[0017] FIG. 7 is a flowchart of a method of wireless
communication.
[0018] FIG. 8 is a conceptual data flow diagram illustrating the
data flow between different means/components in an exemplary
apparatus.
[0019] FIG. 9 is a diagram illustrating an example of a hardware
implementation for an apparatus employing a processing system.
[0020] FIG. 10 is a flowchart of a method of wireless
communication.
[0021] FIG. 11 is a conceptual data flow diagram illustrating the
data flow between different means/components in an exemplary
apparatus.
[0022] FIG. 12 is a diagram illustrating an example of a hardware
implementation for an apparatus employing a processing system.
DETAILED DESCRIPTION
[0023] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0024] Several aspects of telecommunication systems will now be
presented with reference to various apparatus and methods. These
apparatus and methods will be described in the following detailed
description and illustrated in the accompanying drawings by various
blocks, components, circuits, processes, algorithms, etc.
(collectively referred to as "elements"). These elements may be
implemented using electronic hardware, computer software, or any
combination thereof. Whether such elements are implemented as
hardware or software depends upon the particular application and
design constraints imposed on the overall system.
[0025] By way of example, an element, or any portion of an element,
or any combination of elements may be implemented as a "processing
system" that includes one or more processors. Examples of
processors include microprocessors, microcontrollers, graphics
processing units (GPUs), central processing units (CPUs),
application processors, digital signal processors (DSPs), reduced
instruction set computing (RISC) processors, systems on a chip
(SoC), baseband processors, field programmable gate arrays (FPGAs),
programmable logic devices (PLDs), state machines, gated logic,
discrete hardware circuits, and other suitable hardware configured
to perform the various functionality described throughout this
disclosure. One or more processors in the processing system may
execute software. Software shall be construed broadly to mean
instructions, instruction sets, code, code segments, program code,
programs, subprograms, software components, applications, software
applications, software packages, routines, subroutines, objects,
executables, threads of execution, procedures, functions, etc.,
whether referred to as software, firmware, middleware, microcode,
hardware description language, or otherwise.
[0026] Accordingly, in one or more example embodiments, the
functions described may be implemented in hardware, software, or
any combination thereof. If implemented in software, the functions
may be stored on or encoded as one or more instructions or code on
a computer-readable medium. Computer-readable media includes
computer storage media. Storage media may be any available media
that can be accessed by a computer. By way of example, and not
limitation, such computer-readable media can comprise a
random-access memory (RAM), a read-only memory (ROM), an
electrically erasable programmable ROM (EEPROM), optical disk
storage, magnetic disk storage, other magnetic storage devices,
combinations of the aforementioned types of computer-readable
media, or any other medium that can be used to store computer
executable code in the form of instructions or data structures that
can be accessed by a computer.
[0027] FIG. 1 is a diagram illustrating an example of a wireless
communications system and an access network 100. The wireless
communications system (also referred to as a wireless wide area
network (WWAN)) includes base stations 102, UEs 104, an Evolved
Packet Core (EPC) 160, and another core network 190 (such as a 5G
Core (5GC)). The base stations 102 may include macro cells (high
power cellular base station) and/or small cells (low power cellular
base station). The macro cells include base stations. The small
cells include femtocells, picocells, and microcells.
[0028] The base stations 102 configured for 4G LTE (collectively
referred to as Evolved Universal Mobile Telecommunications System
(UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface
with the EPC 160 through backhaul links 132 (e.g., S1 interface).
The base stations 102 configured for 5G NR (collectively referred
to as Next Generation RAN (NG-RAN)) may interface with core network
190 through backhaul links 184. In addition to other functions, the
base stations 102 may perform one or more of the following
functions: transfer of user data, radio channel ciphering and
deciphering, integrity protection, header compression, mobility
control functions (e.g., handover, dual connectivity), inter-cell
interference coordination, connection setup and release, load
balancing, distribution for non-access stratum (NAS) messages, NAS
node selection, synchronization, radio access network (RAN)
sharing, multimedia broadcast multicast service (MBMS), subscriber
and equipment trace, RAN information management (RIM), paging,
positioning, and delivery of warning messages. The base stations
102 may communicate directly or indirectly (e.g., through the EPC
160 or core network 190) with each other over backhaul links 134
(e.g., X2 interface). The backhaul links 134 may be wired or
wireless.
[0029] The base stations 102 may wirelessly communicate with the
UEs 104. Each of the base stations 102 may provide communication
coverage for a respective geographic coverage area 110. There may
be overlapping geographic coverage areas 110. For example, the
small cell 102' may have a coverage area 110' that overlaps the
coverage area 110 of one or more macro base stations 102. A network
that includes both small cell and macro cells may be known as a
heterogeneous network. A heterogeneous network may also include
Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a
restricted group known as a closed subscriber group (CSG). The
communication links 120 between the base stations 102 and the UEs
104 may include UL (also referred to as reverse link) transmissions
from a UE 104 to a base station 102 and/or downlink (DL) (also
referred to as forward link) transmissions from a base station 102
to a UE 104. The communication links 120 may use multiple-input and
multiple-output (MIMO) antenna technology, including spatial
multiplexing, beamforming, and/or transmit diversity. The
communication links may be through one or more carriers. The base
stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10, 15,
20, 100, 400, etc. MHz) bandwidth per carrier allocated in a
carrier aggregation of up to a total of Yx MHz (x component
carriers) used for transmission in each direction. The carriers may
or may not be adjacent to each other. Allocation of carriers may be
asymmetric with respect to DL and UL (e.g., more or less carriers
may be allocated for DL than for UL). The component carriers may
include a primary component carrier and one or more secondary
component carriers. A primary component carrier may be referred to
as a primary cell (PCell) and a secondary component carrier may be
referred to as a secondary cell (SCell).
[0030] Certain UEs 104 may communicate with each other using
device-to-device (D2D) communication link 158. The D2D
communication link 158 may use the DL/UL WWAN spectrum. The D2D
communication link 158 may use one or more sidelink channels, such
as a physical sidelink broadcast channel (PSBCH), a physical
sidelink discovery channel (PSDCH), a physical sidelink shared
channel (PSSCH), and a physical sidelink control channel (PSCCH).
D2D communication may be through a variety of wireless D2D
communications systems, such as for example, FlashLinQ, WiMedia,
Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or
NR.
[0031] The wireless communications system may further include a
Wi-Fi access point (AP) 150 in communication with Wi-Fi stations
(STAs) 152 via communication links 154 in a 5 GHz unlicensed
frequency spectrum. When communicating in an unlicensed frequency
spectrum, the STAs 152/AP 150 may perform a clear channel
assessment (CCA) prior to communicating in order to determine
whether the channel is available.
[0032] The small cell 102' may operate in a licensed and/or an
unlicensed frequency spectrum. When operating in an unlicensed
frequency spectrum, the small cell 102' may employ NR and use the
same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP
150. The small cell 102', employing NR in an unlicensed frequency
spectrum, may boost coverage to and/or increase capacity of the
access network. A base station 102, whether a small cell 102' or a
large cell (e.g., macro base station), may include an eNB, gNodeB
(gNB), or other type of base station. Some base stations 180, such
as a gNB, may operate in a traditional sub 6 GHz spectrum, in
millimeter wave (mmW) frequencies, and/or near mmW frequencies in
communication with the UE 104. When the gNB (e.g., base station
180) operates in mmW or near mmW frequencies, the 180 may be
referred to as an mmW base station. Extremely high frequency (EHF)
is part of the radio frequency (RF) in the electromagnetic
spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength
between 1 millimeter and 10 millimeters. Radio waves in the band
may be referred to as a millimeter wave. Near mmW may extend down
to a frequency of 3 GHz with a wavelength of 100 millimeters. The
super high frequency (SHF) band extends between 3 GHz and 30 GHz,
also referred to as centimeter wave. Communications using the
mmW/near mmW radio frequency band has extremely high path loss and
a short range. The mmW base station (e.g., base station 180) may
utilize beamforming 182 with the UE 104 to compensate for the
extremely high path loss and short range.
[0033] The base station 180 may transmit a beamformed signal to the
UE 104 in one or more transmit directions 182'. The UE 104 may
receive the beamformed signal from the base station 180 in one or
more receive directions 182''. The UE 104 may also transmit a
beamformed signal to the base station 180 in one or more transmit
directions. The base station 180 may receive the beamformed signal
from the UE 104 in one or more receive directions. The base station
180/UE 104 may perform beam training to determine the best receive
and transmit directions for each of the base station 180/UE 104.
The transmit and receive directions for the base station 180 may or
may not be the same. The transmit and receive directions for the UE
104 may or may not be the same.
[0034] The EPC 160 may include a Mobility Management Entity (MME)
162, other MMES 164, a Serving Gateway 166, a Multimedia Broadcast
Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service
Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172.
The MME 162 may be in communication with a Home Subscriber Server
(HSS) 174. The MME 162 is the control node that processes the
signaling between the UEs 104 and the EPC 160. Generally, the MME
162 provide s bearer and connection management. All user Internet
protocol (IP) packets are transferred through the Serving Gateway
166, which itself is connected to the PDN Gateway 172. The PDN
Gateway 172 provides UE IP address allocation as well as other
functions. The PDN Gateway 172 and the BM-SC 170 are connected to
the IP Services 176. The IP Services 176 may include the Internet,
an intranet, an IP Multimedia Subsystem (IMS), a streaming service,
and/or other IP services. The BM-SC 170 may provide functions for
MBMS user service provisioning and delivery. The BM-SC 170 may
serve as an entry point for content provider MBMS transmission, may
be used to authorize and initiate MBMS Bearer Services within a
public land mobile network (PLMN), and may be used to schedule MBMS
transmissions. The MBMS Gateway 168 may be used to distribute MBMS
traffic to the base stations 102 belonging to a Multicast Broadcast
Single Frequency Network (MBSFN) area broadcasting a particular
service, and may be responsible for session management (start/stop)
and for collecting eMBMS related charging information.
[0035] The 5GC 190 may include a Access and Mobility Management
Function (AMF) 192, other AMFs 193, a Session Management Function
(S1VIF) 194, and a User Plane Function (UPF) 195. The AMF 192 may
be in communication with a Unified Data Management (UDM) 196. The
AMF 192 is the control node that processes the signaling between
the UEs 104 and the 5GC 190. Generally, the AMF 192 provides QoS
flow and session management. All user Internet protocol (IP)
packets are transferred through the UPF 195. The UPF 195 provides
UE IP address allocation as well as other functions. The UPF 195 is
connected to the IP Services 197. The IP Services 197 may include
the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS
Streaming Service, and/or other IP services.
[0036] The base station may also be referred to as a gNB, Node B,
evolved Node B (eNB), an access point, a base transceiver station,
a radio base station, a radio transceiver, a transceiver function,
a basic service set (B SS), an extended service set (ESS), a
transmit reception point (TRP), or some other suitable terminology.
The base station 102 provides an access point to the EPC 160 or 5GC
190 for a UE 104. Examples of UEs 104 include a cellular phone, a
smart phone, a session initiation protocol (SIP) phone, a laptop, a
personal digital assistant (PDA), a satellite radio, a global
positioning system, a multimedia device, a video device, a digital
audio player (e.g., MP3 player), a camera, a game console, a
tablet, a smart device, a wearable device, a vehicle, an electric
meter, a gas pump, a large or small kitchen appliance, a healthcare
device, an implant, a sensor/actuator, a display, or any other
similar functioning device. Some of the UEs 104 may be referred to
as IoT devices (e.g., parking meter, gas pump, toaster, vehicles,
heart monitor, etc.). The UE 104 may also be referred to as a
station, a mobile station, a subscriber station, a mobile unit, a
subscriber unit, a wireless unit, a remote unit, a mobile device, a
wireless device, a wireless communications device, a remote device,
a mobile subscriber station, an access terminal, a mobile terminal,
a wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology.
[0037] Referring again to FIG. 1, in certain aspects, the UE 104
may comprise an indication component 198 configured to determine
whether an indication corresponding to a COT is received from a
base station, wherein the indication is for at least one of a set
of CORESETs, a set of QCL assumptions, a set of UL resources, or a
set of spatial relations for determining a default beam and to
determine the default beam from the base station for use during the
COT based on the indication if the indication is received from the
base station. The UE 104 may be configured to transmit or receive a
transmission using the default beam.
[0038] Referring again to FIG. 1, in certain aspects, the base
station 102/180 may comprise an indication component 199 configured
to indicate, to a UE, at least one of a set of CORESETs, a set of
QCL, a set of UL resources, or a set of spatial relations for
determining a default beam, the indication being for use in
determining a default beam COT. The base station 102/180 may be
configured to transmit or receive communication with the UE based
on the default beam
[0039] FIG. 2A is a diagram 200 illustrating an example of a first
subframe within a 5G/NR frame structure. FIG. 2B is a diagram 230
illustrating an example of DL channels within a 5G/NR subframe.
FIG. 2C is a diagram 250 illustrating an example of a second
subframe within a 5G/NR frame structure. FIG. 2D is a diagram 280
illustrating an example of UL channels within a 5G/NR subframe. The
5G/NR frame structure may be frequency division duplex (FDD) in
which for a particular set of subcarriers (carrier system
bandwidth), subframes within the set of subcarriers are dedicated
for either DL or UL, or may be time division duplex (TDD) in which
for a particular set of subcarriers (carrier system bandwidth),
subframes within the set of subcarriers are dedicated for both DL
and UL. In the examples provided by FIGS. 2A, 2C, the 5G/NR frame
structure is assumed to be TDD, with subframe 4 being configured
with slot format 28 (with mostly DL), where D is DL, U is UL, and X
is flexible for use between DL/UL, and subframe 3 being configured
with slot format 34 (with mostly UL). While subframes 3, 4 are
shown with slot formats 34, 28, respectively, any particular
subframe may be configured with any of the various available slot
formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other
slot formats 2-61 include a mix of DL, UL, and flexible symbols.
UEs are configured with the slot format (dynamically through DL
control information (DCI), or semi-statically/statically through
radio resource control (RRC) signaling) through a received slot
format indicator (SFI). Note that the description infra applies
also to a 5G/NR frame structure that is TDD.
[0040] Other wireless communication technologies may have a
different frame structure and/or different channels. A frame (10
ms) may be divided into 10 equally sized subframes (1 ms). Each
subframe may include one or more time slots. Subframes may also
include mini-slots, which may include 7, 4, or 2 symbols. Each slot
may include 7 or 14 symbols, depending on the slot configuration.
For slot configuration 0, each slot may include 14 symbols, and for
slot configuration 1, each slot may include 7 symbols. The symbols
on DL may be cyclic prefix (CP) orthogonal frequency division
multiplex (OFDM) (CP-OFDM) symbols. The symbols on UL may be
CP-OFDM symbols (for high throughput scenarios) or discrete Fourier
transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to
as single carrier frequency-division multiple access (SC-FDMA)
symbols) (for power limited scenarios; limited to a single stream
transmission). The number of slots within a subframe is based on
the slot configuration and the numerology. For slot configuration
0, different numerologies .mu. 0 to 5 allow for 1, 2, 4, 8, 16, and
32 slots, respectively, per subframe. For slot configuration 1,
different numerologies 0 to 2 allow for 2, 4, and 8 slots,
respectively, per subframe. Accordingly, for slot configuration 0
and numerology there are 14 symbols/slot and 211 slots/subframe.
The subcarrier spacing and symbol length/duration are a function of
the numerology. The subcarrier spacing may be equal to
2.sup..mu.*15 kKz, where .mu. is the numerology 0 to 5. As such,
the numerology .mu.=0 has a subcarrier spacing of 15 kHz and the
numerology .mu.=5 has a subcarrier spacing of 480 kHz. The symbol
length/duration is inversely related to the subcarrier spacing.
FIGS. 2A-2D provide an example of slot configuration 0 with 14
symbols per slot and numerology .mu.=0 with 1 slot per subframe.
The subcarrier spacing is 15 kHz and symbol duration is
approximately 66.7 .mu.s.
[0041] A resource grid may be used to represent the frame
structure. Each time slot includes a resource block (RB) (also
referred to as physical RBs (PRBs)) that extends 12 consecutive
subcarriers. The resource grid is divided into multiple resource
elements (REs). The number of bits carried by each RE depends on
the modulation scheme.
[0042] As illustrated in FIG. 2A, some of the REs carry reference
(pilot) signals (RS) for the UE. The RS may include demodulation RS
(DM-RS) (indicated as R.sub.x for one particular configuration,
where 100.times. is the port number, but other DM-RS configurations
are possible) and channel state information reference signals
(CSI-RS) for channel estimation at the UE. The RS may also include
beam measurement RS (BRS), beam refinement RS (BRRS), and phase
tracking RS (PT-RS).
[0043] FIG. 2B illustrates an example of various DL channels within
a subframe of a frame. The physical downlink control channel
(PDCCH) carries DCI within one or more control channel elements
(CCEs), each CCE including nine RE groups (REGs), each REG
including four consecutive REs in an OFDM symbol. A primary
synchronization signal (PSS) may be within symbol 2 of particular
subframes of a frame. The PSS is used by a UE 104 to determine
subframe/symbol timing and a physical layer identity. A secondary
synchronization signal (SSS) may be within symbol 4 of particular
subframes of a frame. The SSS is used by a UE to determine a
physical layer cell identity group number and radio frame timing.
Based on the physical layer identity and the physical layer cell
identity group number, the UE can determine a physical cell
identifier (PCI). Based on the PCI, the UE can determine the
locations of the aforementioned DM-RS. The physical broadcast
channel (PBCH), which carries a master information block (MIB), may
be logically grouped with the PSS and SSS to form a synchronization
signal (SS)/PBCH block. The MIB provides a number of RBs in the
system bandwidth and a system frame number (SFN). The physical
downlink shared channel (PDSCH) carries user data, broadcast system
information not transmitted through the PBCH such as system
information blocks (SIBs), and paging messages.
[0044] As illustrated in FIG. 2C, some of the REs carry DM-RS
(indicated as R for one particular configuration, but other DM-RS
configurations are possible) for channel estimation at the base
station. The UE may transmit DM-RS for the physical uplink control
channel (PUCCH) and DM-RS for the physical uplink shared channel
(PUSCH). The PUSCH DM-RS may be transmitted in the first one or two
symbols of the PUSCH. The PUCCH DM-RS may be transmitted in
different configurations depending on whether short or long PUCCHs
are transmitted and depending on the particular PUCCH format used.
Although not shown, the UE may transmit sounding reference signals
(SRS). The SRS may be used by a base station for channel quality
estimation to enable frequency-dependent scheduling on the UL.
[0045] FIG. 2D illustrates an example of various UL channels within
a subframe of a frame. The PUCCH may be located as indicated in one
configuration. The PUCCH carries uplink control information (UCI),
such as scheduling requests, a channel quality indicator (CQI), a
precoding matrix indicator (PMI), a rank indicator (RI), and hybrid
automatic repeat request (HARD) acknowledgement
(ACK)/not-acknowledgement (NACK) feedback. The PUSCH carries data,
and may additionally be used to carry a buffer status report (B
SR), a power headroom report (PHR), and/or UCI.
[0046] FIG. 3 is a block diagram of a base station 310 in
communication with a UE 350 in an access network. In the DL, IP
packets from the EPC 160 may be provided to a controller/processor
375. The controller/processor 375 implements layer 3 and layer 2
functionality. Layer 3 includes a radio resource control (RRC)
layer, and layer 2 includes a packet data convergence protocol
(PDCP) layer, a radio link control (RLC) layer, and a medium access
control (MAC) layer. The controller/processor 375 provides RRC
layer functionality associated with broadcasting of system
information (e.g., MIB, SIBs), RRC connection control (e.g., RRC
connection paging, RRC connection establishment, RRC connection
modification, and RRC connection release), inter radio access
technology (RAT) mobility, and measurement configuration for UE
measurement reporting; PDCP layer functionality associated with
header compression/decompression, security (ciphering, deciphering,
integrity protection, integrity verification), and handover support
functions; RLC layer functionality associated with the transfer of
upper layer packet data units (PDUs), error correction through ARQ,
concatenation, segmentation, and reassembly of RLC service data
units (SDUs), re-segmentation of RLC data PDUs, and reordering of
RLC data PDUs; and MAC layer functionality associated with mapping
between logical channels and transport channels, multiplexing of
MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs
from TBs, scheduling information reporting, error correction
through HARQ, priority handling, and logical channel
prioritization.
[0047] The transmit (TX) processor 316 and the receive (RX)
processor 370 implement layer 1 functionality associated with
various signal processing functions. Layer 1, which includes a
physical (PHY) layer, may include error detection on the transport
channels, forward error correction (FEC) coding/decoding of the
transport channels, interleaving, rate matching, mapping onto
physical channels, modulation/demodulation of physical channels,
and MIMO antenna processing. The TX processor 316 handles mapping
to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying
(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude
modulation (M-QAM)). The coded and modulated symbols may then be
split into parallel streams. Each stream may then be mapped to an
OFDM subcarrier, multiplexed with a reference signal (e.g., pilot)
in the time and/or frequency domain, and then combined together
using an Inverse Fast Fourier Transform (IFFT) to produce a
physical channel carrying a time domain OFDM symbol stream. The
OFDM stream is spatially precoded to produce multiple spatial
streams. Channel estimates from a channel estimator 374 may be used
to determine the coding and modulation scheme, as well as for
spatial processing. The channel estimate may be derived from a
reference signal and/or channel condition feedback transmitted by
the UE 350. Each spatial stream may then be provided to a different
antenna 320 via a separate transmitter 318TX. Each transmitter
318TX may modulate an RF carrier with a respective spatial stream
for transmission.
[0048] At the UE 350, each receiver 354RX receives a signal through
its respective antenna 352. Each receiver 354RX recovers
information modulated onto an RF carrier and provides the
information to the receive (RX) processor 356. The TX processor 368
and the RX processor 356 implement layer 1 functionality associated
with various signal processing functions. The RX processor 356 may
perform spatial processing on the information to recover any
spatial streams destined for the UE 350. If multiple spatial
streams are destined for the UE 350, they may be combined by the RX
processor 356 into a single OFDM symbol stream. The RX processor
356 then converts the OFDM symbol stream from the time-domain to
the frequency domain using a Fast Fourier Transform (FFT). The
frequency domain signal comprises a separate OFDM symbol stream for
each subcarrier of the OFDM signal. The symbols on each subcarrier,
and the reference signal, are recovered and demodulated by
determining the most likely signal constellation points transmitted
by the base station 310. These soft decisions may be based on
channel estimates computed by the channel estimator 358. The soft
decisions are then decoded and deinterleaved to recover the data
and control signals that were originally transmitted by the base
station 310 on the physical channel. The data and control signals
are then provided to the controller/processor 359, which implements
layer 3 and layer 2 functionality.
[0049] The controller/processor 359 can be associated with a memory
360 that stores program codes and data. The memory 360 may be
referred to as a computer-readable medium. In the UL, the
controller/processor 359 provides demultiplexing between transport
and logical channels, packet reassembly, deciphering, header
decompression, and control signal processing to recover IP packets
from the EPC 160. The controller/processor 359 is also responsible
for error detection using an ACK and/or NACK protocol to support
HARQ operations.
[0050] Similar to the functionality described in connection with
the DL transmission by the base station 310, the
controller/processor 359 provides RRC layer functionality
associated with system information (e.g., MIB, SIBs) acquisition,
RRC connections, and measurement reporting; PDCP layer
functionality associated with header compression/decompression, and
security (ciphering, deciphering, integrity protection, integrity
verification); RLC layer functionality associated with the transfer
of upper layer PDUs, error correction through ARQ, concatenation,
segmentation, and reassembly of RLC SDUs, re-segmentation of RLC
data PDUs, and reordering of RLC data PDUs; and MAC layer
functionality associated with mapping between logical channels and
transport channels, multiplexing of MAC SDUs onto TBs,
demultiplexing of MAC SDUs from TBs, scheduling information
reporting, error correction through HARQ, priority handling, and
logical channel prioritization.
[0051] Channel estimates derived by a channel estimator 358 from a
reference signal or feedback transmitted by the base station 310
may be used by the TX processor 368 to select the appropriate
coding and modulation schemes, and to facilitate spatial
processing. The spatial streams generated by the TX processor 368
may be provided to different antenna 352 via separate transmitters
354TX. Each transmitter 354TX may modulate an RF carrier with a
respective spatial stream for transmission.
[0052] The UL transmission is processed at the base station 310 in
a manner similar to that described in connection with the receiver
function at the UE 350. Each receiver 318RX receives a signal
through its respective antenna 320. Each receiver 318RX recovers
information modulated onto an RF carrier and provides the
information to a RX processor 370.
[0053] The controller/processor 375 can be associated with a memory
376 that stores program codes and data. The memory 376 may be
referred to as a computer-readable medium. In the UL, the
controller/processor 375 provides demultiplexing between transport
and logical channels, packet reassembly, deciphering, header
decompression, control signal processing to recover IP packets from
the UE 350. IP packets from the controller/processor 375 may be
provided to the EPC 160. The controller/processor 375 is also
responsible for error detection using an ACK and/or NACK protocol
to support HARQ operations.
[0054] FIG. 4 depicts a diagram 400 illustrating an example COT 402
for a base station, e.g., for transmitting and/or receiving
communication using an unlicensed frequency band. In unlicensed
bands where the transmission medium is generally shared among
multiple devices (e.g. 60 GHz), the base station may first perform
a clear channel assessment (CCA), e.g., at 404, to determine if the
medium is available for use by the base station. If the CCA clears
(i.e. the base station is successful in its contention for the
medium), the base station may use the channel for the duration of a
COT 402 to schedule grants and transmit/receive data with one or
more UEs. A CCA may be an assessment of energy received on a radio
interface. A lack of energy on the radio interface for a particular
channel may indicate that a channel is clear. A CCA idle period may
be a period when a device may be idle on the channel so that
channel assessment may occur. The COT may be a period when a base
station has secured the channel for a transmission, e.g., a data
transmission, or when a base station has secured the channel for
transmissions by other devices, e.g., a UE. The base station may
inform the UE that it controls the medium by transmitting an
initial signal (IS) 406 at the beginning of the COT, discussed
infra. While the COT 402 in diagram 400, is illustrated as spanning
two slots, two slots is merely one example of a COT duration to
illustrate the concept. The COT may span any number of slots 408.
The IS 406 may provide an indication to the UE informing the UE to
monitor for further communication from the base station during the
COT.
[0055] FIG. 4 also illustrates an example block diagram 420
depicting a base station's transmissions to a UE during the COT
402. Once the base station successfully performs a CCA 404, the
base station may transmit an IS 406 at the beginning of the COT.
The IS 406 informs the UE that the base station has acquired the
channel and is able to transmit a grant and/or data to the UE. In
one aspect, the IS 406 may include Group Common Physical Downlink
Control Channel (GC-PDCCH) information or a reference signal (e.g.
a Channel State Information Reference Signal (CSI-RS)). In another
aspect, the IS 406 may include control information such as a
control resource set (CORESET). The UE decodes the received IS over
a decoding period 422, and the UE may determine that it should
monitor the channel for communications from the base station.
During the decoding period 422, the UE does not monitor for
communication from the base station. Following the decoding period
422, the UE may receive a grant for a DL data transmission, receive
a grant for an UL data transmission, receive DL data, and/or
transmit UL data. For example, the UE may then receive a scheduling
grant 424 containing downlink control information (DCI) for DL/UL
communication. The corresponding data 428 may be communicated at
426. There may be an offset 426 between the grant and the
corresponding transmission/reception of data 428. The base station
may communicate with a single UE in the COT or may communicate with
multiple UEs during the COT. In an example involving communication
with multiple UEs, the base station may send UE-specific grants and
data during the COT. For example, diagram 420 of FIG. 4 illustrates
UE-1 receiving its own scheduling grant 424 followed after an
offset 426 by its corresponding data 428 (either DL or UL data),
and UE-2 receiving its own scheduling grant 430 followed after an
offset 432 by its corresponding data 434.
[0056] In order to receive the communication from the base station,
the UE may need to determine a reception beam from among a
plurality of potential reception beams. While a UE communicating in
the licensed band may simply follow a relationship in which a
default reception beam is QCL with a lowest CORESET ID from a
latest monitored slot, this relationship may lead to problems when
applied in communication in the unlicensed frequency spectrum.
[0057] FIG. 5 illustrates an example block diagram 500 depicting
CORESETs IDs 502, 504, 506 associated with corresponding resources
512, 514, 516 within slots. Each CORESET may indicate where the UE
may receive PDCCH transmissions and may include reference signals
(e.g. Synchronization Signal Block (SSB), CSI-RS, etc.)
corresponding to a particular spatial filter or beam. For example,
CORESET 1 502 may be associated with a beam 522 having a first
direction, CORESET 2 504 may be associated with a beam 524 having a
second direction, and CORESET 3 506 may be associated with a beam
526 having a third direction. Each CORESET may also include a
transmission configuration indication (TCI) state which provides
information about the antenna ports with which the packet common
control channel (PCCCH) antenna ports are quasi co-located. The UE
may receive one or more CORESETs from the base station at the
beginning of any slot.
[0058] If a UE selects the default UE reception (Rx) beam based on
QCL corresponding to the lowest CORESET ID in the latest monitored
slot, the selection could lead to the UE using a beam for which CCA
was not performed or was not successful. For example, referring to
FIG. 5, if Slot 2 was the latest slot and CORESET 1 had the lowest
CORESET ID, then assuming spatial quasi-location between PDCCH and
PDSCH antenna ports, the UE may select a default Rx beam to receive
data on PDSCH in Slot 2 associated with CORESET 1, e.g., beam 522.
However, in this example, the base station has not checked beam 1
and will not use CORESET 1 that corresponds to beam 1. Thus,
selection of the subset of CORESET QCL for transmission in a given
COT may lead the UE to determine an incorrect default Rx/Tx beam
and may degrade communication between the UE and the base station.
Similarly, the UE may rely on a QCL assumption for determining a
default Rx/Tx beam that is not consistent with the set of QCL
assumptions selected by the base station.
[0059] In order to address this problem, a base station may
indicate to the UE(s) selected CORESET(s) (e.g., CORESET 2 and
CORESET 3 in FIG. 5) from among the possible CORESETs or selected
CORESET QCLs from among the possible QCL assumptions for use in a
given COT 402, e.g., as illustrated at 606 in FIG. 6. The selection
may be based on the beams used by the base station to perform CCA
and/or the beams for which CCA was successful. The default beam
(e.g., from among beam 1, beam 2, beam 3) may be determined based
on the selected subset of CORESETs (CORESET 2, or CORESET 3) or
selected CORESET QCLs rather than from the entire set of CORESETs
or from the entire set of QCL assumptions. A QCL assumption is a
relationship that indicates that the Rx/Tx signal will share
properties with another signal. For example, the Rx/Tx beam may
have a defined relationship to the beam used for another signal,
e.g., a reference signal. Thus, the QCL assumption provides the
relationship defining the properties that are shared between the
Rx/Tx signal and the other signal. There may be a set of potential
QCL assumptions, and the base station may select a subset of the
QCL assumptions for use in a particular COT. Aspects described
herein may include a base station signaling information about the
selected CORESET(s) or the selected CORESET QCL(s). Aspects
described herein may also include the UE receive the information
about the selected CORESET(s) or the selected CORESET QCL(s)and use
the information to select a default reception beam for
communication with the base station.
[0060] The concept of QCL may be used to improve the channel
estimation performance. One channel on one antenna port may be
estimated using information about the channel on another antenna
port. One antenna port may be considered QCL to another antenna
port when they have the same or similar properties. The two antenna
ports may have the same or similar properties because they are
located near each other in space, oriented the same or similar in
space, the antennas used have similar properties, or some
combination of these or other aspects of the antennas lead to the
antennas having similar properties.
[0061] For example, antennas may be considered to be QCL based on
one or more of frequency shift, received power for each antenna
port, Doppler spread, Doppler shift, delay spread, average gain, an
average delay, received timing, a number of significant channel
taps, or some combination of these or other figures of merit
related to the antenna ports. For QCL antenna ports, one or more of
these figures of merit are the same or similar for each of the
antenna ports that are considered QCL. One or more of these
properties may be determined based on received reference signals or
other received signals.
[0062] FIG. 6 illustrates a diagram 600 of an example communication
flow between a base station 602 and a UE 604 including aspects
presented herein. The UE may determine whether an indication of a
set of CORESET(s) or a set of QCL assumption(s) is received from
the base station 602. If the CORESETs/QCL assumptions selected by
the base station are indicated to the UE at 606, the UE may
determine, at 612, a default reception beam based on the indicated
set. For example, the UE may use a default Rx beam based on the
lowest CORESET ID from among the indicated set or based on a QCL
assumption having a lowest identifier. The selected set of
CORESETs/QCL assumptions may be based on beams for which the base
station performs CCA and/or succeeds in performing CCA. Following
the determination of the default beam, the UE may use the default
beam to receive data 610 and/or to transmit data 614. FIG. 6 also
illustrates a grant 608 that may correspond to a grant for DL data
610 or UL data 614.
[0063] If selected CORESET QCLs are indicated, the CORESETs whose
QCLs are not selected may follow one of selected CORESET QCL based
on certain rule. For example, if a CORESET with an un-selected QCL
is used to transmit to the UE, the data received in connection with
the CORESET may be transmitted and/or received based on a QCL of
the lowest CORESET ID from among the CORESETs with selected QCLs or
from among the selected set of CORESETs. Thus, a default reception
beam may follow a QCL relationship with a lowest CORESET ID from
among the CORESETs selected by the base station and indicated to
the UE at 606. Likewise, a default reception beam may follow a QCL
relationship with a lowest CORESET ID from among the QCL
assumptions selected by the base station and indicated to the UE at
606.
[0064] In addition to indicating a subset of CORESETs/QCL
assumptions at 606 for determining a default Rx beam, the base
station may also indicate a subset of UL resources and/or a subset
of spatial relations for particular signals, at 606. The indication
of a subset of UL resources and/or subset of spatial relations for
particular signals may be used by the UE, at 612, to determine a
default transmission beam, e.g., to transmit data 614. The UL
resources indicated at 606 may include any of SRS, PUCCH, and/or
PUSCH. The spatial relations that may be indicated to the UE, at
606, can include those used for SRS/PUCCH/PUSCH, and default Tx
beam that is determined at 612 can be used for PUCCH/PUSCH/SRS. For
example, a base station can indicate, at 606, a subset of PUCCH
resources, e.g., selected Tx beams, whose beams are allowed by
listen before talk (LBT) or CCA in abase station initiated COT. A
Tx beam of PUSCH scheduled by DCI format 0_0 in the COT may follow
Tx beam of lowest PUCCH resource among the subset of selected PUCCH
resources in an active bandwidth part (BWP).
[0065] The indication 606 may be made to the UE in any of a number
of ways. For example, the base station may explicitly signal the
selected CORESETs, QCL assumptions, UL resources, and/or spatial
relations to the UE. A base station may explicitly signal CORESETs
or CORESET QCLs in PDCCH, such as in a group common PDCCH at the
beginning of COT. For example, the indication of a set of CORESETs
selected from a plurality of CORESETS or a set of QCL assumptions
selected from a plurality of QCL assumptions may include signaling
identifying the set of CORESETS or the set of QCL assumptions. The
indication may be included in a control channel received in the at
least one COT.
[0066] In another example, the indication may be implicitly
signaled to the UE. For example, the base station may signal such
information to the UE in CSI-RS resources with the same QCLs as the
selected CORESET(s)/QCL assumptions. The CSI-RS resources may be at
the beginning of a COT, so that the UE can determine the beam(s)
for use during the COT.
[0067] FIG. 7 is a flowchart 700 of a method of wireless
communication. The method may be performed by a UE or a component
of a UE (e.g., the UE 104, 350, 604, 1150; the apparatus 802/802';
the processing system 914, which may include the memory 360 and
which may be the entire UE 350 or a component of the UE 350, such
as the TX processor 368, the RX process or 356, and/or the
controller/processor 359). According to various aspects, one or
more of the illustrated operations of the method of flowchart 700
may be omitted, transposed, and/or contemporaneously performed. The
UE may implement the method of diagram 600. The method may enable a
UE to more accurately determine a default beam when communicating
with a base station using beamforming over an unlicensed
spectrum.
[0068] At 706, the UE determines whether an indication
corresponding to a COT is received from a base station. For
example, 706 may be performed by indication component 808 of
apparatus 802. In some aspects, the indication may be for at least
one of a set of CORESETs, a set of QCL assumptions, a set of UL
resources, or a set of spatial relations for determining a default
beam.
[0069] At 708, the UE determines the default beam from the base
station for use during the COT. For example, 708 may be performed
by default beam component 810 of apparatus 802. In some aspects,
the UE determines the default beam from the base station for use
during the COT based on the indication if the indication is
received from the base station. Otherwise, the UE may determine the
default beam in another manner at 714.
[0070] The UE may then communicate during the COT using the default
beam. In some aspects, for example, at 710, the UE may transmit a
transmission using the default beam. For example, 710 may be
performed by transmission component 806 of apparatus 802. In some
aspects, for example, at 712, the UE may receive a transmission
using the default beam. For example, 712 may be performed by
reception component 804 of apparatus 802.
[0071] In some aspects, for example, at 702, the UE may receive the
indication of the set of CORESETs or of the set of QCL assumptions.
For example, 702 may be performed by reception component 804 of
apparatus 802. In some aspects, the default beam may comprise a
default reception beam that may be selected based on a lowest
CORESET identifier (ID) from among the set of CORESETs or the set
of QCL assumptions. In some aspects, for a CORESET that is not
comprised in the set of CORESETs, the UE may determine the default
beam based on a lowest CORESET ID from among the set of CORESETs or
the set of QCL assumptions.
[0072] In some aspects, for example, at 704, the UE may receive the
indication of the set of UL resources or the set of spatial
relations for determining the default beam. For example, 704 may be
performed by reception component 804 of apparatus 802. In some
aspects, the default beam may comprise a default transmission beam
that may be selected based on the indication of the set of UL
resources or the set of spatial relations for determining the
default beam. The UL resources may correspond to at least one of a
Sounding Reference Signal (SRS), an uplink control channel, or an
uplink data channel. The spatial relations for determining the
default beam may comprise spatial relations for selecting at least
one of a Sounding Reference Signal (SRS), an uplink control
channel, or an uplink data channel for an uplink transmission from
the UE. The indication may comprise UL resources for a first uplink
channel, and wherein the UE determines the default beam for a
second uplink channel based on a beam used for the first uplink
channel.
[0073] FIG. 8 is a conceptual data flow diagram 800 illustrating
the data flow between different means/components in an exemplary
apparatus 802. The apparatus may be a UE or a component of a UE.
The apparatus may perform the method of flowchart 700. The
apparatus includes an indication component 808 configured to
determine whether an indication corresponding to a COT is received
from a base station, wherein the indication is for at least one of
a set of CORESETs, a set of QCL assumptions, a set of UL resources,
or a set of spatial relations for determining a default beam, e.g.,
as described in connection with 706 of FIG. 7. The apparatus
comprises a default beam component 810 configured to determine the
default beam from the base station for use during the COT based on
the indication if the indication is received from the base station,
e.g., as described in connection with 708 of FIG. 7. The reception
component 804 is configured to receive receiving a transmission
from base station 850 using the default beam, e.g., as discussed in
connection with 712 of FIG. 7. The transmission component 806 is
configured to transmit a transmission using the default beam, e.g.,
as discussed in connection with 710 of FIG. 7. The indication
component 808 may be configured to receive the indication of the
set of CORESETs or of the set of QCL assumptions, wherein the
default beam comprises a default reception beam that is selected
based on a lowest CORESET ID from among the set of CORESETs or the
set of QCL assumptions, e.g., as discussed in connection with 702
of FIG. 7. The indication component 808 may be configured to
receive the indication of the set of CORESETs or of the set of QCL
assumptions, wherein for a CORESET that is not comprised in the set
of CORESETs, the UE determines the default beam based on a lowest
CORESET identifier ID from among the set of CORESETs or the set of
QCL assumptions, e.g., as discussed in connection with 702 of FIG.
7. The indication component 808 may be configured to receive the
indication of the set of UL resources or the set of spatial
relations for determining the default beam, wherein the default
beam comprises a default transmission beam that is selected based
on the indication of the set of UL resources or the set of spatial
relations for determining the default beam, e.g., as discussed in
connection with 704 of FIG. 7.
[0074] The apparatus may include additional components that perform
each of the blocks of the algorithm in the aforementioned
flowcharts of FIGS. 6 and 7. As such, each block in the
aforementioned flowcharts of FIGS. 6 and 7 may be performed by a
component and the apparatus may include one or more of those
components. The components may be one or more hardware components
specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0075] FIG. 9 is a diagram 900 illustrating an example of a
hardware implementation for an apparatus 802' employing a
processing system 914. The processing system 914 may be implemented
with a bus architecture, represented generally by the bus 924. The
bus 924 may include any number of interconnecting buses and bridges
depending on the specific application of the processing system 914
and the overall design constraints. The bus 924 links together
various circuits including one or more processors and/or hardware
components, represented by the processor 904, the components 804,
806, 808, 810 and the computer-readable medium/memory 906. The bus
924 may also link various other circuits such as timing sources,
peripherals, voltage regulators, and power management circuits,
which are well known in the art, and therefore, will not be
described any further.
[0076] The processing system 914 may be coupled to a transceiver
910. The transceiver 910 is coupled to one or more antennas 920.
The transceiver 910 provides a means for communicating with various
other apparatus over a transmission medium. The transceiver 910
receives a signal from the one or more antennas 920, extracts
information from the received signal, and provides the extracted
information to the processing system 914, specifically the
reception component 804. In addition, the transceiver 910 receives
information from the processing system 914, specifically the
transmission component 806, and based on the received information,
generates a signal to be applied to the one or more antennas 920.
The processing system 914 includes a processor 904 coupled to a
computer-readable medium/memory 906. The processor 904 is
responsible for general processing, including the execution of
software stored on the computer-readable medium/memory 906. The
software, when executed by the processor 904, causes the processing
system 914 to perform the various functions described supra for any
particular apparatus. The computer-readable medium/memory 906 may
also be used for storing data that is manipulated by the processor
904 when executing software. The processing system 914 further
includes at least one of the components 804, 806, 808, 810. The
components may be software components running in the processor 904,
resident/stored in the computer readable medium/memory 906, one or
more hardware components coupled to the processor 904, or some
combination thereof. The processing system 914 may be a component
of the UE 350 and may include the memory 360 and/or at least one of
the TX processor 368, the RX processor 356, and the
controller/processor 359.
[0077] In one configuration, the apparatus 802/802' for wireless
communication includes means for determining whether an indication
corresponding to a COT is received from a base station. The
indication is for at least one of a set of CORESETs, a set of QCL
assumptions, a set of UL resources, or a set of spatial relations
for determining a default beam. The apparatus includes means for
determining the default beam from the base station for use during
the COT based on the indication when the indication is received
from the base station. The apparatus includes means for
transmitting or receiving a transmission using the default beam.
The apparatus further includes means for receiving the indication
of the set of CORESETs or of the set of QCL assumptions. The
default beam comprising a default reception beam that is selected
based on a lowest CORESET ID from among the set of CORESETs or the
set of QCL assumptions. The apparatus further includes means for
receiving the indication of the set of CORESETs or of the set of
QCL assumptions. For a CORESET that is not comprised in the set of
CORESETs, the UE determines the default beam based on a lowest
CORESET ID from among the set of CORESETs or the set of QCL
assumptions. The apparatus further includes means for receiving the
indication of the set of uplink resources or the set of spatial
relations for determining the default beam. The default beam
comprising a default transmission beam that is selected based on
the indication of the set of uplink resources or the set of spatial
relations for determining the default beam. The aforementioned
means may be one or more of the aforementioned components of the
apparatus 802 and/or the processing system 914 of the apparatus
802' configured to perform the functions recited by the
aforementioned means. As described supra, the processing system 914
may include the TX Processor 368, the RX Processor 356, and the
controller/processor 359. As such, in one configuration, the
aforementioned means may be the TX Processor 368, the RX Processor
356, and the controller/processor 359 configured to perform the
functions recited by the aforementioned means.
[0078] FIG. 10 is a flowchart 1000 of a method of wireless
communication. The method may be performed by a base station or a
component of a base station (e.g., the base station 102, 180, 310,
602, 850; the apparatus 1102/1102'; the processing system 1214,
which may include the memory 376 and which may be the entire base
station 310 or a component of the base station 310, such as the TX
processor 316, the RX processor 370, and/or the
controller/processor 375). According to various aspects, one or
more of the illustrated operations of the method of flowchart 1000
may be omitted, transposed, and/or contemporaneously performed. The
UE may implement the method of diagram 600. The method may enable a
UE to more accurately determine a default beam when communicating
with a base station using beamforming over an unlicensed
spectrum.
[0079] At 1002, the base station transmits, to a UE, an indication
of at least one of a set of CORESETs, a set of QCL assumptions, a
set of UL resources, or a set of spatial relations for determining
a default beam. For example, 1002 may be performed by indication
component 1108 of apparatus 1102. In some aspects, the indication
may be used in determining a default beam for use in a COT. An
example indication 606 is described in connection with FIG. 6. The
indication may be based on a CCA performed by the base station. In
some aspects, the indication may indicate the set of CORESETs. In
some aspects, the indication indicates the set of QCL assumptions.
The default beam may be determined to be a default reception beam.
In some aspects, the indication indicates the set of uplink
resources. The default beam may comprise a default transmission
beam. The uplink resources may comprise at least one of a SRS, an
uplink control channel, or an uplink data channel. The indication
may indicate the set of spatial relations for determining the
default beam, and the default beam may comprise a default
transmission beam. In some aspects, the set of spatial relations
for determining the default beam comprise spatial relations for
selecting at least one of a SRS, an uplink control channel, or an
uplink data channel. In some aspects, the indication may comprise
uplink resources for a first uplink channel, and the default beam
for a second uplink channel may be indicated based on a beam used
for the first uplink channel.
[0080] At 1004, the base station may transmit a transmission to the
UE based on the default beam based on the indication transmitted at
1002. For example, 1004 may be performed by transmission component
1106 of apparatus 1102. In some aspects, the indication may
indicate the set of CORESETs, and may provide the UE with
information to determine a default reception beam. In some aspects,
the indication may indicate the set of QCL assumptions, and may
provide the UE with information to determine a default reception
beam.
[0081] At 1006, the base station may receive a transmission from
the UE based on a default beam based on the indication transmitted
at 1002. For example, 1006 may be performed by reception component
1104 of apparatus 1102. In some aspects, the indication may
indicate the set of UL resources, and may provide the UE with
information to determine a default transmission beam. The UL
resources may comprise at least one of an SRS, an uplink control
channel, or an uplink data channel. As another example, the
indication may indicate the set of spatial relations for
determining a default transmission beam. The spatial relations for
determining the default beam may comprise spatial relations for
selecting at least one of an SRS, an uplink control channel, or an
uplink data channel. The indication may comprise UL resources for a
first uplink channel, and wherein the default beam for a second
uplink channel is indicated based on a beam used for the first
uplink channel.
[0082] FIG. 11 is a conceptual data flow diagram 1100 illustrating
the data flow between different means/components in an exemplary
apparatus 1102. The apparatus may be a base station or a component
of a base station. The apparatus may perform the method of
flowchart 1000. The apparatus includes an indication component 1108
configured to transmit, to a UE (e.g. UE 1150), an indication of at
least one of a set of CORESETs, a set of QCL assumptions, a set of
UL resources, or a set of spatial relations for determining a
default beam, the indication being for use in determining a default
beam for use in a COT, e.g., as described in connection with 1002
of FIG. 10. The apparatus includes a reception component 1104
configured to receive a transmission from the UE based on the
default beam, e.g., as described in connection with 1006 of FIG.
10. The apparatus includes a transmission component 1106 configured
to transmit a transmission to the UE based on the default beam,
e.g., as described in connection with 1004 of FIG. 10.
[0083] The apparatus may include additional components that perform
each of the blocks of the algorithm in the aforementioned
flowcharts of FIGS. 6 and 10. As such, each block in the
aforementioned flowcharts of FIGS. 6 and 10 may be performed by a
component and the apparatus may include one or more of those
components. The components may be one or more hardware components
specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0084] FIG. 12 is a diagram 1200 illustrating an example of a
hardware implementation for an apparatus 1102' employing a
processing system 1214. The processing system 1214 may be
implemented with a bus architecture, represented generally by the
bus 1224. The bus 1224 may include any number of interconnecting
buses and bridges depending on the specific application of the
processing system 1214 and the overall design constraints. The bus
1224 links together various circuits including one or more
processors and/or hardware components, represented by the processor
1204, the components 1104, 1106, 1108, and the computer-readable
medium/memory 1206. The bus 1224 may also link various other
circuits such as timing sources, peripherals, voltage regulators,
and power management circuits, which are well known in the art, and
therefore, will not be described any further.
[0085] The processing system 1214 may be coupled to a transceiver
1210. The transceiver 1210 is coupled to one or more antennas 1220.
The transceiver 1210 provides a means for communicating with
various other apparatus over a transmission medium. The transceiver
1210 receives a signal from the one or more antennas 1220, extracts
information from the received signal, and provides the extracted
information to the processing system 1214, specifically the
reception component 1104. In addition, the transceiver 1210
receives information from the processing system 1214, specifically
the transmission component 1106, and based on the received
information, generates a signal to be applied to the one or more
antennas 1220. The processing system 1214 includes a processor 1204
coupled to a computer-readable medium/memory 1206. The processor
1204 is responsible for general processing, including the execution
of software stored on the computer-readable medium/memory 1206. The
software, when executed by the processor 1204, causes the
processing system 1214 to perform the various functions described
supra for any particular apparatus. The computer-readable
medium/memory 1206 may also be used for storing data that is
manipulated by the processor 1204 when executing software. The
processing system 1214 further includes at least one of the
components 1104, 1106, 1108. The components may be software
components running in the processor 1204, resident/stored in the
computer readable medium/memory 1206, one or more hardware
components coupled to the processor 1204, or some combination
thereof. The processing system 1214 may be a component of the base
station 310 and may include the memory 376 and/or at least one of
the TX processor 316, the RX processor 370, and the
controller/processor 375
[0086] In one configuration, the apparatus 1102/1102' for wireless
communication includes means for sending, to a UE, an indication of
at least one of a set of CORESETs, a set of QCL assumptions, a set
of UL resources, or a set of spatial relations for determining a
default beam. The indication being for use in determining a default
beam for use in a COT. The apparatus includes means for
transmitting a transmission to the UE based on the default beam.
The apparatus includes means for receiving a transmission from the
UE based on the default beam. The aforementioned means may be one
or more of the aforementioned components of the apparatus 1102
and/or the processing system 1214 of the apparatus 1102' configured
to perform the functions recited by the aforementioned means. As
described supra, the processing system 1214 may include the TX
Processor 316, the RX Processor 370, and the controller/processor
375. As such, in one configuration, the aforementioned means may be
the TX Processor 316, the RX Processor 370, and the
controller/processor 375 configured to perform the functions
recited by the aforementioned means.
[0087] The present disclosure relates to communication enhancements
between the base station and the UE through the base station
indicating to the UE which CORESET(s) or QCL assumptions are
selected for a COT. The UE may use the indication to determine a
default beam for the communication. In addition, the base station
may indicate selected uplink (UL) resources or spatial
relationships for the COT that the UE may use to determine a
default beam. At least one advantage of the disclosure is that the
UE may be configured to more accurately determine a default beam
when communicating with a base station using beamforming over an
unlicensed spectrum.
[0088] It is understood that the specific order or hierarchy of
blocks in the processes/flowcharts disclosed is an illustration of
exemplary approaches. Based upon design preferences, it is
understood that the specific order or hierarchy of blocks in the
processes/flowcharts may be rearranged. Further, some blocks may be
combined or omitted. The accompanying method claims present
elements of the various blocks in a sample order, and are not meant
to be limited to the specific order or hierarchy presented.
[0089] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." The word "exemplary" is used herein to mean "serving
as an example, instance, or illustration." Any aspect described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other aspects. Unless specifically
stated otherwise, the term "some" refers to one or more.
Combinations such as "at least one of A, B, or C," "one or more of
A, B, or C," "at least one of A, B, and C," "one or more of A, B,
and C," and "A, B, C, or any combination thereof" include any
combination of A, B, and/or C, and may include multiples of A,
multiples of B, or multiples of C. Specifically, combinations such
as "at least one of A, B, or C," "one or more of A, B, or C," "at
least one of A, B, and C," "one or more of A, B, and C," and "A, B,
C, or any combination thereof" may be A only, B only, C only, A and
B, A and C, B and C, or A and B and C, where any such combinations
may contain one or more member or members of A, B, or C. All
structural and functional equivalents to the elements of the
various aspects described throughout this disclosure that are known
or later come to be known to those of ordinary skill in the art are
expressly incorporated herein by reference and are intended to be
encompassed by the claims. Moreover, nothing disclosed herein is
intended to be dedicated to the public regardless of whether such
disclosure is explicitly recited in the claims. The words "module,"
"mechanism," "element," "device," and the like may not be a
substitute for the word "means." As such, no claim element is to be
construed as a means plus function unless the element is expressly
recited using the phrase "means for."
* * * * *