WO2021212296A1

WO2021212296A1 - Implicit determination of beam failure detection reference signal in a dormant bandwidth part

Info

Publication number: WO2021212296A1
Application number: PCT/CN2020/085772
Authority: WO
Inventors: Wooseok Nam; Tao Luo; Peng Cheng; Yan Zhou; Huilin Xu; Peter Pui Lok Ang
Original assignee: Qualcomm Incorporated
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2021-10-28

Abstract

A method, a computer-readable medium, and an apparatus are provided for wireless communication at a user equipment (UE). The apparatus receives a configuration for one or more reference signals for a first bandwidth part (BWP) of a cell; switches to a dormant BWP the cell; and determines whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP.

Description

IMPLICIT DETERMINATION OF BEAM FAILURE DETECTION REFERENCE SIGNAL IN A DORMANT BANDWIDTH PART

BACKGROUND

Technical Field

The present disclosure relates generally to communication systems, and more particularly, to wireless communication including directional transmission and reception.

Introduction

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.

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

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.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided for wireless communication at a user equipment (UE) . The apparatus receives a configuration for one or more reference signals for a first bandwidth part (BWP) of a cell; switches to a dormant BWP for the cell; and determines whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP.

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

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network.

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.

FIG. 3 is a diagram illustrating an example of a base station and user equipment (UE) in an access network.

FIG. 4 is a diagram illustrating a transition between non-dormant BWPs and a dormant BWP for a secondary cell (SCell) .

FIG. 5 is a frequency diagram illustrating examples of a dormant BWP, synchronization signal block (SSB) , and channel state information reference signal (CSI-RS) .

FIG. 6 is a flowchart of a method of wireless communication in accordance with aspects presented herein.

DETAILED DESCRIPTION

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.

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.

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.

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.

FIG. 1 is a diagram illustrating an example of a wireless communications system and an access network 100 that includes UEs 104 and base stations 102 and 180. The UE may be configured with a dormant BWP, e.g., that enables the UE to save power at times on a secondary cell (SCell) because the UE may refrain from monitoring PDCCH on the dormant BWP. As illustrated in FIG. 1, the UE 104 and the base station 180 may utilize beamforming 182, e.g., to compensate for higher path loss and short range for some frequencies. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

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.

For example, the UE may perform beam failure detection (BFD) by measuring reference signals that are either explicitly or implicitly indicated for BFD. For the dormant BWP, the UE may not be explicitly configured with BFD reference signals, and may not be configured for monitoring PDCCH that may be used to implicitly identify reference signals for BFD. The UE may use reference signals that are configured for a proxy BWP to perform BFD for the dormant BWP. The present disclosure provides example criteria, rules, etc., that the UE may use to determine whether to use a reference signal configured for a proxy BWP to perform BFD for a dormant BWP.

Referring again to FIG. 1, in certain aspects, the UE 104 may be configured for one or more reference signals (e.g., SSB, CSI-RS, etc. ) for a BWP of a cell. The UE 104 may switch to a dormant BWP for the cell. The UE may include a proxy reference signal determination component 198 configured to determine whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP, e.g., according to any combination of the criteria presented herein. Although the following description may be focused on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

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 (e.g., a 5G Core (5GC) ) . The base stations 102 may include macrocells (high power cellular base station) and/or small cells (low power cellular base station) . The macrocells include base stations. The small cells include femtocells, picocells, and microcells.

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 first 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 second 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 third backhaul links 134 (e.g., X2 interface) . The third backhaul links 134 may be wired or wireless.

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 macrocells 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 uplink (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 fewer 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) .

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, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, LTE, or NR.

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.

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 and/or be referred to as an eNB, gNodeB (gNB) , or another type of base station. Some base stations, such as gNB 180 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 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the 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 (RF) band (e.g., 3 GHz –300 GHz) has extremely high path loss and a short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include a plurality of antennas, such as antenna elements, antenna panels, and/or antenna arrays to facilitate the beamforming.

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 provides 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 PS 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.

The core network 190 may include a Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 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 core network 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 Packet Switch (PS) Streaming (PSS) Service, and/or other IP services.

The base station may include and/or be referred to as a gNB, Node B, eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , 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 core network 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.

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 duplexed (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 duplexed (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.

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) 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 μ0 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 μ, there are 14 symbols/slot and 2 ^μ slots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2 ^μ*15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=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 μ=2 with 4 slots per subframe. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

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.

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 _x for one particular configuration, where 100x 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) .

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.

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. The UE may transmit sounding reference signals (SRS) . The SRS may be transmitted in the last symbol of a subframe. The SRS may have a comb structure, and a UE may transmit SRS on one of the combs. The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

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 (HARQ) ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR) , a power headroom report (PHR) , and/or UCI.

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 service data adaptation protocol (SDAP) layer, 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.

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.

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.

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.

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.

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.

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.

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.

At least one of the TX processor 368, the RX processor 356, and the controller/processor 359 may be configured to perform aspects in connection with 198 of FIG. 1.

A UE may be configured for carrier aggregation for multiple component carriers. Each component carrier may correspond to a serving cell. 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) . In order to save power in carrier aggregation scenarios, the UE may be configured for dormancy behavior for an SCell. One of the BWPs on an SCell may be designated as a dormant BWP. The UE may transition between a first state (e.g., an active state) and a dormant state for the SCell based on a switch to the dormant BWP. When the UE is in the dormant BWP for the SCell, the UE may not be expected to monitor for a PDCCH on the SCell and may not transmit uplink signals on the SCell. A base station may indicate a transition between the dormant and non-dormant BWPs for the SCell in downlink control information (DCI) in the PCell. The base station may transmit the DCI, with the indication about transition between the dormant and non-dormant BWP for the SCell, to the UE during a discontinuous reception (DRX) active time for the PCell. In this example, the DCI may comprise a scheduling DCI. Additionally or alternatively, the base station may transmit the DCI, with the indication about transition between the dormant and non-dormant BWP for the SCell, outside of a DRX active time for the PCell. As an example, the DCI may comprise a wake-up signal (WUS) prior to a DRX active time.

The dormant BWP may not be configured with PDCCH monitoring. For example, an RRC information element (IE) for PDCCH confirmation (e.g., “pdcch-Config” ) may be absent in the BWP configuration for the UE to indicate that no PDCCH monitoring is configured for the BWP for the SCell. While on the dormant BWP, the UE may transition to a dormant state for the SCell. The UE may stop monitoring for PDCCH on the SCell and may not transmit uplink communication on the SCell. If configured for such measurements, the UE may perform CSI measurement, automatic gain control (AGC) , and/or beam management for the SCell even though the UE does not monitor for PDCCH on the SCell.

A designated BWP may be associated with dormant behavior for the UE. The designated BWP may be referred to as the dormant BWP. A non-dormant BWP may be designated as the first BWP to which the UE switches when switching away from the dormant BWP. A first non-dormant BWP may be indicated for the UE for a BWP switch during a DRX active time and may be referred to as “FNDB_I” or “NDB_I. ” A first non-dormant BWP may be indicated for the UE for a BWP switch outside of a DRX active time and may be referred to as “FNDB_O” or “NDB_O. ” In some examples, the FNDB_I may be the same BWP as the FNDB_O. In other examples, the FNDB_I may be a different BWP than the FNDB_O.

FIG. 4 illustrates a diagram showing aspects of a BWP switch for an SCell from a non-dormant BWP 402 to the dormant BWP 404. The switch may be triggered by DCI that the UE receives from the base station. While on the dormant BWP 404 for the SCell, the UE may operate in a dormant state for the SCell, e.g., not monitoring PDCCH or transmission uplink communication. The UE may switch to a non-dormant BWP 406, e.g., in response to DCI received on the PCell. The PCell remains on a non-dormant BWP 408. Although the PCell may switch BWPs, the PCell remains on a non-dormant BWP, so that the UE can monitor for PDCCH from the base station at least on the PCell. As illustrated, BWP 406 is an FNDB_I and/or FNDB_O depending on the timing of the BWP switch from the dormant BWP 404 to the non-dormant BWP 406 relative to a DRX cycle for the UE.

As illustrated in FIG. 1, a UE and a base station may communicate using beamformed communication, e.g., using transmit and receive directions 182’ and 182”. UE may measure beam failure detection (BFD) reference signals (RS) from the base station in order to maintain beam-paired links with the base station. The UE may monitor the quality of the beams that it uses for communication with the base station. A BFD procedure may be used to identify problems in beam quality and a beam failure recovery (BFR) procedure may be used when a beam failure is detected. For monitoring active link performances, a UE may perform measurements of at least one signal, e.g., reference signals, for beam failure detection. The measurements may include deriving a metric similar to a Signal to Interference plus Noise Ratio (SINR) for the signal, or RSRP strength or block error rate (BLER) of a reference control channel chosen by base station and/or implicitly derived by UE based on the existing RRC configuration. The reference signal may comprise any of CSI-RS, Physical Broadcast Channel (PBCH) , a synchronization signal (SS) , or other reference signals for time and/or frequency tracking, etc.

In some cases, the UE may determine a configured metric such as block error rate (BLER) for a reference signal. The measurement (s) may indicate the UE’s ability to transmit an uplink transmission to the base station using the beam. Thresholds may be defined in tracking the radio link conditions, the threshold (s) may correspond to an RSRP, a BLER, etc. that indicates an in-sync condition and/or an out-of-sync condition of the radio link. An “out-of-sync” condition may indicate that the radio link condition is poor, and an “in-sync” condition may indicate that the radio link condition is acceptable, and the base station is likely to receive a transmission transmitted on the radio link. An Out-of-Sync condition may be declared when a block error rate for the radio link falls below a threshold over a specified time interval. An in-sync condition may be declared when a block error rate for the radio link is better than a threshold over a specified time interval. If the UE receives a threshold number of consecutive out-of-sync measurements over a period of time, the UE may declare a beam failure.

When a beam failure is detected, a UE may take appropriate actions to recover the connection. For example, after multiple out-of-sync measurements, the UE may transmit a beam failure recovery signal to initiate recovery of the connection with the base station.

The BFD RS for the UE to use may be explicitly configured for the UE by the base station in some examples. Alternatively, if a particular RS is not explicitly configured for the UE for use for BFD (e.g., as a BFD RS) , the UE may implicitly determine a RS to monitor for BFD. For example, the UE may monitor one or more periodic channel state information reference signal (P-CSI-RS) that are quasi co-located with a demodulation reference signal (DM-RS) of a PDCCH monitored for the UE, in an implicit manner even though the P-CSI-RS is not explicitly configured as a BFD RS.

As the UE does not monitor PDCCH in the dormant BWP, e.g., no PDCCH-configuration is provided to the UE for the SCell, there may not be a beam-paired link to be maintained by monitoring explicitly configured BFD RS (s) for the dormant BWP of the SCell. There may be no PDCCH for the UE to use to implicitly determine a BFD RS for the SCell.

The UE may use another BWP as a proxy BWP for performing the BFD for the SCell. The UE may determine the explicit or implicit configuration of BFD RS (s) based on the proxy BWP. The proxy BWP may be, e.g., the BWP for the SCell that the UE used prior to the transition to the dormant BWP. For example, in the FIG. 4, the UE may use the non-dormant BWP 402 as a proxy BWP for BFD for the dormant BWP. The proxy BWP may be a first non-dormant BWP, e.g., FNDB-I or FNDB-O (e.g. BWP 406 in FIG. 4. The proxy BWP may correspond to the dormant BWP (e.g., 404 in FIG. 4) with a dummy control resource set (CORESET) configuration (e.g., a CORESET without associated search space sets) .

Aspects presented herein may be used by the UE to perform BFD in a dormant BWP that more accurately represents the performance of the proxy BWP. The present disclosure provides constraints and rules for identifying particular reference signals of a proxy BWP for use for BFD for an SCell on a dormant BWP.

If a synchronization signal block (SSB) is explicitly configured as a BFD RS in the proxy BWP (e.g., the proxy BWP contains the SSB) , the UE may determine to use the same SSB as a BFD RS in the dormant BWP if the frequency domain assignment for the dormant BWP contains the SSB band and has the same numerology as the SSB. FIG. 5 illustrates an example frequency diagram 500 showing a frequency domain assignment 504 for a dormant BWP 502, e.g., for an SCell of the UE. If the SSB configured as a BFD RS for the PCell has an frequency band shown at 506, the UE may use the SSB to perform BFD for the SCell, because the frequency band of the SSB at 506 overlaps with the frequency allocation of the dormant BWP 502. If the SSB configured as a BFD RS for the PCell has an frequency band shown at 508, the UE may determine not to use the SSB to perform BFD for the SCell, because the frequency band of the SSB at 508 is not within the frequency allocation of the dormant BWP 502.

If a periodic CSI-RS is explicitly configured for the UE as a BFD RS in the proxy BWP, the UE may use the same P-CSI-RS as a BFD RS to perform BFD in the dormant BWP of the SCell if the frequency domain assignment for the dormant BWP overlaps with the frequency occupation of the CSI-RS and the CSI resource setting (e.g., “CSI-ResourceConfig IE” ) in the dormant BWP contains the same P-CSI-RS resource. For example, in FIG. 5, the UE may determine to use the CSI-

RS

510 and 512 that have a frequency occupation that overlaps with the dormant BWP 502. The UE may determine not to use the CSI-RS 514 that does not overlap in frequency with the dormant BWP 502. By determining whether to use the P-CSI-RS as a BFD RS for the dormant BWP based on whether the dormant BWP shares frequency resources with the P-CSI-RS and the CSI resource setting in the dormant BWP contains the P-CSI-RS for the proxy BWP may help to ensure that the same P-CSI-RS is transmitted by the base station both in the dormant BWP and the proxy BWP.

If the UE determines that the conditions for the SSB that is configured as a BFD RS are met and determines that the conditions for the P-CSI-RS that is configured as a BFD RS for the proxy BWP are met, the UE may use both the SSB and P-CSI-RS of the proxy BWP to perform BFD for the dormant BWP.

If the condition of shared frequency resources with the P-CSI-RS or CSI resource setting containing the P-CSI-RS is not satisfied but overlapping frequency resources and the same numerology condition for an SSB is met, the UE may trace back a QCL chain of the CSI-RS to find a source SSB. Then, the UE may monitor that SSB of the proxy BWP for BFD for the dormant BWP of the SCell. A tracking reference signal (TRS) or CSI-RS may have other CSI-RS or SSB as QCL-TypeD sources. The UE may use the QCL relationships to determine a source SSB.

If no BFD RS is explicitly configured in the proxy BWP, the UE may determine an implicitly indicated RS for BFD. If a CSI resource setting in the dormant BWP for the SCell includes P-CSI-RS resources that are QCLed with the DM-RS of the PDCCH monitored by the UE in the proxy BWP, the UE may monitor the RS (e.g., the P-CSI-RS that is QCL with the DM-RS of the PDCCH) for BFD for the dormant BWP of the SCell.

Otherwise, if the frequency range and numerology conditions are met for an SSB that is not explicitly configured as a BFD RS (e.g., if the SSB has a frequency band contained in the frequency allocation of the dormant BWP) , the UE can trace back the QCL chain of the TCI states of CORESETs in the proxy BWP in order to find the source SSB (i.e., QCL-TypeD source) . Then, the UE may monitor the determined source SSB for the proxy BWP to perform BFD for the dormant BWP for the SCell.

In addition to determining which reference signals of the proxy BWP to use for BFD, the UE may also determine which non-dormant BWP to use as the proxy BWP for the purposes of determining the BFD RS to use for the dormant BWP.

As noted above, the UE may use the FNDB_I and/or the FNDB_O as the proxy BWP. As an example, if the FNDB_I and/or the FNDB_O are the same, the UE may implicitly determine BFD RS (s) in the associated dormant BWP, e.g., based on the rules discussed above.

If the FNDB_I and the FNDB_O are different BWPs, the UE may further consider whether the two BWPs (e.g., FNDB_I and FNDB_O) have at least one common BFD RS.If the two BWPs do have at least one common BFD RS, the UE may use the common BFD RS (s) for determining BFD RS (s) in the dormant BWP, e.g., based on the rules described above. Thus, the UE may consider a BFD RS if it is common to both the FNDB_I and the FNDB_O and may exclude, or not consider, a BFD RS if it is not common to both the FNDB_I and the FNDB_O.

The BFD RS (s) in each BWP (e.g., FNDB_I and FNDB_O) can be configured either explicitly or implicitly in the manner indicated above.

If there are no common BFD RS that the UE can use for BFD for the dormant BWP, the UE may select one of the two BWP (e.g., FNDB_I or FNDB_O) for determining BFD RS (s) in DB. As an example, the UE may select one of the BWPs and may apply the conditions described above to determine whether to use reference signals of the selected BWP to perform BFD for the dormant BWP for the SCell.

One of the two BWPs can be explicitly indicated to the UE as the proxy BWP, e.g., in higher layer signaling or signaling from a network. Then, the UE may select the BWP based on the explicit indication that the UE received from the base station.

Alternatively, the UE may apply a rule to select between the BWPs to use as a proxy BWP. As one example, the UE may select the BWP having a lower index. In another example, the UE may select the BWP associated with a the smaller PDCCH monitoring periodicity. The UE may also use different criteria or a different rule to select the BWP.

FIG. 6 is a flowchart 600 of a method of wireless communication. The method may be performed by a UE (e.g., the

UE

104, 350; a processing system, 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 processor 356, and/or the controller/processor 359) . Optional aspects are illustrated with a dashed line. The method may enable a UE to make an improved selection of a reference signal to use for performing beam failure detection for a dormant BWP.

At 602, the UE receives a configuration for one or more reference signals for a first BWP of a cell. The cell may be an SCell, for example. The first BWP may be a non-dormant BWP. The first BWP may be a FNDB_I, a FNDB_O, a BWP used before a transition to a dormant BWP, etc. The one or more reference signals for the first BWP may comprise at least one of a first SSB configured for the BFD for the first BWP, a first P-CSI-RS configured for the BFD for the first BWP, a second P-CSI-RS that has a quasi co-location relationship to a PDCCH monitored by the UE on the first BWP, or a source SSB that has a quasi co-location relationship to the first P-CSI-RS or the second P-CSI-RS on the first BWP.

At 604, the UE switches to a dormant BWP for the cell. For example, the UE may switch to the dormant BWP, and adjust operation, as described in connection with FIG. 4.

At 608, the UE determines whether to use a reference signal configured for the first BWP to perform BFD for the dormant BWP.

The UE may determine, at 608, to use an SSB that is configured for the BFD for the first BWP to perform the BFD for the dormant BWP if a frequency domain assignment for the dormant BWP comprises a frequency band for the SSB, e.g., as described in connection with FIG. 5. The UE may determine to use the SSB that is configured for the BFD for the first BWP to perform the BFD for the dormant BWP further based on the dormant BWP having a same numerology as the SSB. The UE may determine not to use the SSB to perform the BFD for the dormant BWP if the frequency domain assignment for the dormant BWP does not include the frequency band for the SSB or if the dormant BWP does not have the same numerology as the SSB.

The UE may determine to use a P-CSI-RS that is configured for the BFD for the first BWP to perform the BFD for the dormant BWP if a frequency domain assignment for the dormant BWP overlaps with a frequency occupation for the P-CSI-RS, e.g., as described in connection with FIG. 5. The UE may determine to use the P-CSI-RS that is configured for the BFD for the first BWP to perform the BFD for the dormant BWP further based on a channel state information resource setting for the dormant BWP comprises a same P-CSI-RS resource.

If a frequency domain assignment for the dormant BWP does not overlap with a frequency occupation for a P-CSI-RS configured for the BFD for the first BWP or a channel state information setting for the dormant BWP does not comprises a same P-CSI-RS resource, the UE may determine, as illustrated at 610, a source SSB for the first BWP based on one or more quasi co-location relationships for the P-CSI-RS.

At 612, the UE may perform the BFD for the dormant BWP based on the source SSB for the first BWP.

In no reference signals are configured for the BFD for the first BWP, the UE may determine to use a P-CSI-RS that is configured for the first BWP and that has a QCL relationship with a DM-RS of a PDCCH monitored by the UE in the first BWP. The first BWP may correspond to a FNDB_I and a FNDB_O.

If no reference signals are configured for the BFD for the first BWP and if a frequency domain assignment for the dormant BWP comprises a frequency band for a SSB and the dormant BWP has a same numerology as the SSB, the UE may determine, at 608, to use a source SSB based on a quasi co-location relationship of a TCI state of one or more CORESETs in the first BWP. The first BWP may correspond to a first non-dormant BWP indicated inside an FNDB_I and an FNDB_O.

An FNDB_I may be different than an FNDB_O. The UE may determine, at 608, to use a common BFD reference signal for the FNDB_I and the FNDB_O to perform the BFD for the dormant BWP. The common BFD reference signal may be explicitly configured for the FNDB_I or the FNDB_O. The common BFD reference signal may be implicitly configured for the FNDB_I or the FNDB_O.

The FNDB_I may be different than the FNDB_O. As illustrated at 606, the UE may determine a proxy BWP from the FNDB_I or the FNDB_O for the BFD for the dormant BWP. The proxy BWP may be determined based on at least one of: a configuration received from a base station, or a defined rule (e.g., BWP with the lowest ID, BWP associated with a smaller PDCCH monitoring periodicity, etc. ) .

A UE or a component of a UE may include components that perform each of the blocks of the algorithm in the aforementioned flowchart of FIG. 6. 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.

In one configuration, the UE or component of the UE may include means for performing any of the aspects of the method in FIG. 6. The aforementioned means may be one or more of the aforementioned components of the UE and/or a processing system of the UE configured to perform the functions recited by the aforementioned means. As described supra, the processing system 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.

The following examples are illustrative only and aspects thereof may be combined with aspects of other embodiments or teaching described herein, without limitation.

Example 1 is a method of wireless communication at a UE, comprising: receiving a configuration for one or more reference signals for a first BWP of a cell; switching to a dormant BWP for the cell; and determining whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP.

In Example 2, the method of Example 1 further includes that the cell is an SCell.

In Example 3, the method of Example 1 or 2 further includes that the one or more reference signals for the first BWP comprise at least one of: a first SSB configured for the beam failure detection for the first BWP, a first P-CSI-RS configured for the beam failure detection for the first BWP, a second P-CSI-RS that has a quasi co-location relationship to a PDCCH monitored by the UE on the first BWP, or a source SSB that has a quasi co-location relationship to the first P-CSI-RS or the second P-CSI-RS on the first BWP.

In Example 4, the method of any of Example 1-3 further includes that the UE determines to use a SSB that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell if a frequency domain assignment for the dormant BWP comprises a frequency band for the SSB.

In Example 5, the method of any of Example 1-4 further includes that the UE determines to use the SSB that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell further based on the dormant BWP having a same numerology as the SSB.

In Example 6, the method of any of Example 1-5 further includes that the UE determines not to use the SSB to perform the beam failure detection for the cell if the frequency domain assignment for the dormant BWP does not include the frequency band for the SSB or if the dormant BWP does not have the same numerology as the SSB.

In Example 7, the method of any of Example 1-6 further includes that the UE determines to use a P-CSI-RS that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell if a frequency domain assignment for the dormant BWP overlaps with a frequency occupation for the P-CSI-RS.

In Example 8, the method of any of Example 1-7 further includes that the UE determines to use the P-CSI-RS that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell further based on a channel state information resource setting for the dormant BWP comprises a same P-CSI-RS resource.

In Example 9, the method of any of Example 1-8 further includes that if a frequency domain assignment for the dormant BWP overlaps with a frequency occupation for a P-CSI-RS configured for the beam failure detection for the first BWP and a channel state information resource setting for the dormant BWP does not comprises a same P-CSI-RS resource, the method further comprising: determining a source SSB for the first BWP based on one or more quasi co-location relationships for the P-CSI-RS; and performing the beam failure detection for the cell based on the source SSB for the first BWP.

In Example 10, the method of any of Example 1-9 further includes that if no reference signals are configured for the beam failure detection for the first BWP, the UE determines to use a P-CSI-RS that is configured for the first BWP and that has a quasi co-location relationship with a DM-RS of a PDCCH monitored by the UE in the first BWP.

In Example 11, the method of any of Example 1-10 further includes that the first BWP corresponds to a FNDB_I for a primary cell and a FNDB_O for the primary cell.

In Example 12, the method of any of Example 1-11 further includes that if no reference signals are configured for the beam failure detection for the first BWP and if a frequency domain assignment for the dormant BWP comprises a frequency band for a SSB of the first BWP and the dormant BWP has a same numerology as the SSB, the UE determines to use a source SSB based on a quasi co-location relationship of a TCI state of one or more CORESETs in the first BWP.

In Example 13, the method of any of Example 1-12 further includes that the first BWP corresponds to a FNDB_I for a primary cell and a FNDB_O for the primary cell.

In Example 14, the method of any of Example 1-13 further includes that a FNDB_I for a primary cell is different than a FNDB_O for the primary cell, and wherein the UE determines to use a common beam failure detection reference signal for the FNDB_I and the FNDB_O to perform the beam failure detection for the cell.

In Example 15, the method of any of Example 1-14 further includes that the common beam failure detection reference signal is explicitly configured for the FNDB_I or the FNDB_O.

In Example 16, the method of any of Example 1-15 further includes that the common beam failure detection reference signal is implicitly configured for the FNDB_I or the FNDB_O.

In Example 17, the method of any of Example 1-16 further includes that a FNDB_I) for a primary cell is different than a FNDB_O for the primary cell, the method further comprising: determining a proxy BWP from the FNDB_I or the FNDB_O for the beam failure detection for the dormant BWP.

In Example 18, the method of any of Example 1-17 further includes that the proxy BWP is determined based on at least one of: a configuration received from a base station, or a defined rule.

Example 19 is a device including one or more processors and one or more memories in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the device to implement a method as in any of Examples 1-18.

Example 20 is a system or apparatus including means for implementing a method or realizing an apparatus as in any of Examples 1-18.

Example 21 is a non-transitory computer readable medium storing instructions executable by one or more processors to cause the one or more processors to implement a method as in any of Examples 1-18.

It is understood that the specific order or hierarchy of blocks in the processes /flowcharts disclosed is an illustration of example 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.

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. ”

Claims

A method of wireless communication at a user equipment (UE) , comprising:

receiving a configuration for one or more reference signals for a first bandwidth part (BWP) of a cell;

switching to a dormant BWP for the cell; and

determining whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP.
The method of claim 1, wherein the cell is a secondary cell (SCell) .
The method of claim 1, wherein the one or more reference signals for the first BWP comprise at least one of:

a first synchronization signal block (SSB) configured for the beam failure detection for the first BWP,

a first periodic channel state information reference signal (P-CSI-RS) configured for the beam failure detection for the first BWP,

a second P-CSI-RS that has a quasi co-location relationship to a physical downlink control channel (PDCCH) monitored by the UE on the first BWP, or

a source SSB that has a quasi co-location relationship to the first P-CSI-RS or the second P-CSI-RS on the first BWP.
The method of claim 1, wherein the UE determines to use a synchronization signal block (SSB) that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell if a frequency domain assignment for the dormant BWP comprises a frequency band for the SSB.
The method of claim 4, wherein the UE determines to use the SSB that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell further based on the dormant BWP having a same numerology as the SSB.
The method of claim 5, wherein the UE determines not to use the SSB to perform the beam failure detection for the cell if the frequency domain assignment for the dormant BWP does not include the frequency band for the SSB or if the dormant BWP does not have the same numerology as the SSB.
The method of claim 1, wherein the UE determines to use a periodic channel state information reference signal (P-CSI-RS) that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell if a frequency domain assignment for the dormant BWP overlaps with a frequency occupation for the P-CSI-RS.
The method of claim 7, wherein the UE determines to use the P-CSI-RS that is configured for the beam failure detection for the first BWP to perform the beam failure detection for the cell further based on a channel state information resource setting for the dormant BWP comprises a same P-CSI-RS resource.
The method of claim 1, wherein if a frequency domain assignment for the dormant BWP overlaps with a frequency occupation for a periodic channel state information reference signal (P-CSI-RS) configured for the beam failure detection for the first BWP and a channel state information resource setting for the dormant BWP does not comprises a same P-CSI-RS resource, the method further comprising:

determining a source synchronization signal block (SSB) for the first BWP based on one or more quasi co-location relationships for the P-CSI-RS; and

performing the beam failure detection for the cell based on the source SSB for the first BWP.
The method of claim 1, wherein if no reference signals are configured for the beam failure detection for the first BWP, the UE determines to use a periodic channel state information reference signal (P-CSI-RS) that is configured for the first BWP and that has a quasi co-location relationship with a demodulation reference signal (DM-RS) of a physical downlink control channel (PDCCH) monitored by the UE in the first BWP.
The method of claim 10, wherein the first BWP corresponds to a first non-dormant BWP indicated inside a discontinuous reception (DRX) active time (FNDB_I) for a primary cell and a first non-dormant BWP indicated outside the DRX active time (FNDB_O) for the primary cell.
The method of claim 1, wherein if no reference signals are configured for the beam failure detection for the first BWP and if a frequency domain assignment for the dormant BWP comprises a frequency band for a synchronization signal block (SSB) of the first BWP and the dormant BWP has a same numerology as the SSB, the UE determines to use a source SSB based on a quasi co-location relationship of a transmission configuration indication (TCI) state of one or more control resource sets (CORESETs) in the first BWP.
The method of claim 12, wherein the first BWP corresponds to a first non-dormant BWP indicated inside a discontinuous reception (DRX) active time (FNDB_I) for a primary cell and a first non-dormant BWP indicated outside the DRX active time (FNDB_O) for the primary cell.
The method of claim 1, wherein a first non-dormant BWP indicated inside a discontinuous reception (DRX) active time (FNDB_I) for a primary cell is different than a first non-dormant BWP indicated outside the DRX active time (FNDB_O) for the primary cell, and

wherein the UE determines to use a common beam failure detection reference signal for the FNDB_I and the FNDB_O to perform the beam failure detection for the cell.
The method of claim 14, wherein the common beam failure detection reference signal is explicitly configured for the FNDB_I or the FNDB_O.
The method of claim 14, wherein the common beam failure detection reference signal is implicitly configured for the FNDB_I or the FNDB_O.
The method of claim 1, wherein a first non-dormant BWP indicated inside a discontinuous reception (DRX) active time (FNDB_I) for a primary cell is different than a first non-dormant BWP indicated outside the DRX active time (FNDB_O) for the primary cell, the method further comprising:

determining a proxy BWP from the FNDB_I or the FNDB_O for the beam failure detection for the dormant BWP.
The method of claim 17, wherein the proxy BWP is determined based on at least one of:

a configuration received from a base station, or

a defined rule.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for receiving a configuration for one or more reference signals for a first bandwidth part (BWP) of a cell;

means for switching to a dormant BWP for the cell; and

means for determining whether to use a reference signal configured for the first BWP to perform beam failure detection for the dormant BWP.
The apparatus of claim 19, further comprising means to perform the method of any of claims 2-18.
An apparatus for wireless communication at a user equipment (UE) , comprising:

memory; and

at least one processor coupled to the memory, the at least one processor and the memory configured to perform the method of any of claims 1-18.
A non-transitory computer-readable medium storing computer executable code for wireless communication at a user equipment (UE) , the code when executed by a processor causes the processor to perform the method of any of claims 1-18.