# US 12,120,656 B2 · Beam failure recovery method and device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,656 B2 - Document ID: US12120656B2 - Status: Granted - Kind: B2 - Application number: 17/945,991 - Filed: 2022-09-15 - Published: 2023-01-05 - Granted: 2024-10-15 - Earliest claimed: 2018-02-12 - Assignees: Vivo Mobile Communication Co., Ltd. - Applicants: Vivo Mobile Communication Co.,Ltd. - Inventors: Li Chen; Yumin Wu; Jing Liang - Web page: https://patentgrep.com/patent/US12120656B2 ## CPC - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04B 7/06964: {Re-selection of one or more beams after beam failure} - H04B 7/06966: {using beam correspondence; using channel reciprocity, e.g. downlink beam training based on uplink sounding reference signal [SRS]} - H04W 72/54: based on quality criteria - H04W 72/563: of the wireless resources - H04W 74/002: {Transmission of channel access control information} - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 76/19: Connection re-establishment - H04B 7/088: {using beam selection} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04W 16/28: using beam steering - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/0838: using contention-free random access [CFRA] - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION ## Abstract A beam failure recovery method and device are provided. The method includes: after a beam failure recovery event is triggered, user equipment (UE) monitoring a physical downlink control channel (PDCCH) scrambled with a cell radio network temporary identifier (C-RNTI) in a first control channel resource set (CORESET) for beam failure recovery, and monitoring a PDCCH scrambled with a C-RNTI in a second CORESET. ## Claims ### Claim 1 A beam failure recovery method, comprising: after a beam failure recovery event is triggered, when a timer is running, user equipment (UE) monitoring a physical downlink control channel (PDCCH) scrambled with a cell radio network temporary identifier (C-RNTI) in a first control channel resource set (CORESET) for beam failure recovery, and monitoring a PDCCH scrambled with a C-RNTI in a second CORESET; wherein the timer is one of a beam failure recovery timer, a contention-free random access (CFRA)-based beam failure recovery timer or a contention-based random access (CBRA)-based beam failure recovery timer; wherein the timer starts in response to a beam failure indication being received. ### Claim 2 (depends on 1) The beam failure recovery method according to claim 1, further comprising: when a media access control (MAC) layer of the UE determines that beam failure recovery fails, transmitting, to a radio resource control (RRC) layer, indication information indicating that beam failure recovery fails, wherein the indication information is used for instructing the RRC layer to trigger a radio link failure. ### Claim 3 (depends on 1) The beam failure recovery method according to claim 1, further comprising: when a C-RNTI is monitored in the first CORESET before the beam failure recovery timer, the CFRA-based beam failure recovery timer or the CBRA-based beam failure recovery timer expires, determining that beam failure recovery succeeds. ### Claim 4 (depends on 3) The beam failure recovery method according to claim 3, wherein, after the determining that beam failure recovery succeeds, the method further comprises at least one of: stopping a beam failure recovery timer; stopping a beam failure recovery request transmission counter; stopping transmitting a random access preamble to a network side device; or indicating to the network side device that beam failure recovery succeeds. ### Claim 5 (depends on 1) The beam failure recovery method according to claim 1, wherein, before the monitoring the PDCCH scrambled with the C-RNTI in the first CORESET for beam failure recovery, the method further comprises: the UE transmitting a random access preamble to a network side device by using a random access procedure, wherein the random access preamble is used as a beam failure recovery request. ### Claim 6 User equipment (UE), comprising a processor, a storage, and a computer program stored in the storage and configured to be executed by the processor, wherein the processor is configured to execute the computer program to implement following steps: after a beam failure recovery event is triggered, when a timer is running, monitoring a physical downlink control channel (PDCCH) scrambled with a cell radio network temporary identifier (C-RNTI) in a first control channel resource set (CORESET) for beam failure recovery, and monitoring a PDCCH scrambled with a C-RNTI in a second CORESET; wherein the timer is one of a beam failure recovery timer, a CFRA-based beam failure recovery timer or a CBRA-based beam failure recovery timer; wherein the timer starts in response to a beam failure indication being received. ### Claim 7 (depends on 6) The UE according to claim 6, wherein the processor is configured to execute the computer program to further implement following step: when a media access control (MAC) layer of the UE determines that beam failure recovery fails, transmitting, to a radio resource control (RRC) layer, indication information indicating that beam failure recovery fails, wherein the indication information is used for instructing the RRC layer to trigger a radio link failure. ### Claim 8 (depends on 6) The UE according to claim 6, wherein the processor is configured to execute the computer program to further implement following step: when a C-RNTI is monitored in the first CORESET before the beam failure recovery timer, the CFRA-based beam failure recovery timer or the CBRA-based beam failure recovery timer expires, determining that beam failure recovery succeeds. ### Claim 9 (depends on 8) The UE according to claim 8, wherein the processor is configured to execute the computer program to further implement following step: after the determining that beam failure recovery succeeds, performing at least one of: stopping a beam failure recovery timer; stopping a beam failure recovery request transmission counter; stopping transmitting a random access preamble to a network side device; or indicating to the network side device that beam failure recovery succeeds. ### Claim 10 (depends on 6) The UE according to claim 6, wherein the processor is configured to execute the computer program to further implement following step: before the monitoring the PDCCH scrambled with the C-RNTI in the first CORESET for beam failure recovery, transmitting a random access preamble to a network side device by using a random access procedure, wherein the random access preamble is used as a beam failure recovery request. ### Claim 11 A non-transitory computer-readable storage medium, storing therein a computer program, wherein the computer program is configured to be executed by a processor to implement following steps: after a beam failure recovery event is triggered, when a timer is running, monitoring a physical downlink control channel (PDCCH) scrambled with a cell radio network temporary identifier (C-RNTI) in a first control channel resource set (CORESET) for beam failure recovery, and monitoring a PDCCH scrambled with a C-RNTI in a second CORESET; wherein the timer is one of a beam failure recovery timer, a CFRA-based beam failure recovery timer or a CBRA-based beam failure recovery timer; wherein the timer starts in response to a beam failure indication being received. ### Claim 12 (depends on 11) The non-transitory computer-readable storage medium according to claim 11, wherein the computer program is configured to be executed by a processor to further implement following step: when a media access control (MAC) layer of user equipment (UE) determines that beam failure recovery fails, transmitting, to a radio resource control (RRC) layer, indication information indicating that beam failure recovery fails, wherein the indication information is used for instructing the RRC layer to trigger a radio link failure. ### Claim 13 (depends on 11) The non-transitory computer-readable storage medium according to claim 11, wherein the computer program is configured to be executed by a processor to further implement following step: when a C-RNTI is monitored in the first CORESET before the beam failure recovery timer, the CFRA-based beam failure recovery timer or the CBRA-based beam failure recovery timer expires, determining that beam failure recovery succeeds. ### Claim 14 (depends on 13) The non-transitory computer-readable storage medium according to claim 13, wherein the computer program is configured to be executed by a processor to further implement following step: after the determining that beam failure recovery succeeds, performing at least one of: stopping a beam failure recovery timer; stopping a beam failure recovery request transmission counter; stopping transmitting a random access preamble to a network side device; or indicating to the network side device that beam failure recovery succeeds. ### Claim 15 (depends on 11) The non-transitory computer-readable storage medium according to claim 11, wherein the computer program is configured to be executed by a processor to further implement following step: before the monitoring the PDCCH scrambled with the C-RNTI in the first CORESET for beam failure recovery, transmitting a random access preamble to a network side device by using a random access procedure, wherein the random access preamble is used as a beam failure recovery request.