# US 10,873,381 B2 · Apparatus and method for beam failure recovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,381 B2 - Document ID: US10873381B2 - Status: Granted - Kind: B2 - Application number: 16/504,228 - Filed: 2019-07-06 - Published: 2019-10-31 - Granted: 2020-12-22 - Earliest claimed: 2017-09-07 - Assignees: Futurewei Technologies, Inc. - Applicants: Futurewei Technologies, Inc. - Inventors: Young Hoon Kwon; Bin Liu; Pengfei Xia - Web page: https://patentgrep.com/patent/US10873381B2 ## CPC - 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]} - H04B 7/18582: {Arrangements for data linking, i.e. for data framing, for error recovery, for multiple access} - H04L 5/00: Arrangements affording multiple use of the transmission path - H04L 5/0023: {Time-frequency-space} - 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)} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 56/0005: {synchronizing of arrival of multiple uplinks} - H04W 56/003: {Arrangements to increase tolerance to errors in transmission or reception timing} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 16/28: using beam steering - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 74/0838: using contention-free random access [CFRA] - H04B: TRANSMISSION - 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) ## Abstract The disclosure relates to technology for assigning resources to user equipment for a beam failure recovery by a base station. The base station identifies a beam failure random access channel (BRACH) resource holding beam correspondence with a synchronization signal (SS) block resource covering the user equipment, and assigns the user equipment one or more BRACH preambles for each BRACH resource assigned to the user equipment, excluding the BRACH resource holding beam correspondence with the SS block resource covering the user equipment. ## Claims ### Claim 1 A non-transitory computer-readable medium storing computer instructions for assigning resources to a user equipment for a beam failure recovery by a base station that, when executed by one or more processors of the base station, cause the base station to perform the steps of: configuring a plurality of new beam identification reference signals; identifying one or more of the new beam identification reference signals corresponding to one or more current beams of the user equipment; assigning to the user equipment one or more beam failure random access channel (BRACH) resource, including a BRACH preamble, for each of the plurality of the new beam identification reference signals excluding the new beam identification reference signals corresponding to all the current beams of the user equipment; and transmitting the assignment of the BRACH resources to the user equipment. ### Claim 2 (depends on 1) The non-transitory computer-readable medium of claim 1, wherein a spatial domain of at least one of the new beam identification reference signals assigned a BRACH resource covers a spatial domain of one or more other new beam identification reference signals. ### Claim 3 (depends on 2) The non-transitory computer-readable medium of claim 2, wherein the instructions further cause the base station to further perform the step of categorizing a plurality of synchronization signals of the plurality of new beam identification reference signals into first and second groups, wherein: the first group of the plurality of synchronization signals does not cover a spatial domain of the one or more current beams; and each of the second group of the plurality of synchronization signals covers a spatial domain of at least one of the one or more current beams. ### Claim 4 (depends on 3) The non-transitory computer-readable medium of claim 3, wherein, for each of the second group of the synchronization signals, the instructions further cause the base station to further perform the steps of: assigning the user equipment one or more BRACH resources, wherein a number of BRACH resources assigned for each synchronization signal corresponds to a number of new beam identification reference signals corresponding with the synchronization signal and covering a spatial domain of the one or more current beams. ### Claim 5 (depends on 1) The non-transitory computer-readable medium of claim 1, wherein each of the new beam identification reference signals has a different beam direction. ### Claim 6 (depends on 1) The non-transitory computer-readable medium of claim 1, wherein the instructions further cause the base station to further perform the steps of: receiving a beam failure recovery request (BFRR) from the user equipment, identifying a new candidate beam, upon detection of a beam failure between the base station and the user equipment; and identifying the new candidate beam upon receiving a BRACH preamble assigned for the user equipment at a BRACH resource. ### Claim 7 (depends on 6) The non-transitory computer-readable medium of claim 6, wherein the BRACH resources support N * (K/(K-1)) user equipment, where N BRACH preambles are available for each BRACH resource and K is a number of BRACH resources with different beams. ### Claim 8 (depends on 1) The non-transitory computer-readable medium of claim 1, wherein there are more than one current beams of the user equipment. ### Claim 9 A method for a beam failure recovery, comprising: identifying one or more current beams serving a user equipment; monitoring a signal quality of the one or more current beams to identify when the signal quality falls below a first threshold value; identifying one or more new beam identification reference signals corresponding to the one or more current beams of the user equipment; identifying a new beam having a signal quality above a second threshold value from the one or more new beam identification reference signals, excluding the new beam identification reference signals corresponding to one or more of the current beams of the user equipment; and transmitting a beam failure recovery request (BFRR) on a beam failure random access channel (BRACH) resource corresponding to the identified new beam. ### Claim 10 (depends on 1) The method of claim 1, wherein there are more than one current beams of the user equipment. ### Claim 11 A method for assigning resources to a user equipment for a beam failure recovery by a base station, comprising: configuring a plurality of new beam identification reference signals; identifying one or more of the new beam identification reference signals corresponding to one or more current beams of the user equipment; assigning to the user equipment one or more beam failure random access channel (BRACH) resources, including a BRACH preamble, for each of the plurality of the one or more the new beam identification reference signals excluding the new beam identification reference signals corresponding to all the current beams of the user equipment; and transmitting the assignment of the BRACH resource to the user equipment. ### Claim 12 (depends on 11) The method of claim 11, wherein a spatial domain of at least one of the new beam identification reference signals assigned a BRACH resource covers a spatial domain of one or more other new beam identification reference signals. ### Claim 13 (depends on 1) The method of claim 1, further comprising categorizing a plurality of synchronization signals of the plurality of new beam identification reference signals into first and second groups, wherein the first group of the plurality of synchronization signals does not cover a spatial domain of the one or more current beams; and each of the second group of the plurality of synchronization signals covers a spatial domain of at least one of the one or more current beams. ### Claim 14 (depends on 13) The method of claim 13, wherein for each of the second group of synchronization signals, the method further comprises: assigning the user equipment one or more BRACH resources, wherein a number of BRACH resources assigned for each synchronization signal corresponds to a number of new beam identification reference signals corresponding with the synchronization signal and covering a spatial domain of the one or more current beams. ### Claim 15 (depends on 11) The method of claim 11, wherein each of the new beam identification reference signals has a different beam direction. ### Claim 16 (depends on 11) The method of claim 11, further comprising: receiving a beam failure recovery request (BFRR) from the user equipment, identifying a new candidate beam, upon detection of a beam failure between the base station and the user equipment; and identifying the new candidate beam upon receiving a BRACH preamble assigned for the user equipment at a BRACH resource. ### Claim 17 (depends on 16) The method of claim 16, wherein the BRACH resources support N * (K/(K-1)) user equipment, where N BRACH preambles are available for each BRACH resource and K is a number of BRACH resources with different beams. ### Claim 18 (depends on 11) The method of claim 11, wherein there are more than one current beams of the user equipment.