# US 11,310,833 B2 · RACH procedure with timing alignment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,310,833 B2 - Document ID: US11310833B2 - Status: Granted - Kind: B2 - Application number: 16/556,146 - Filed: 2019-08-29 - Published: 2021-03-04 - Granted: 2022-04-19 - Earliest claimed: 2019-08-29 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Ori Auslender; Ran Berliner; Ambarish Tripathi; Junsheng Han; Muhammad Nazmul Islam; Michael Levitsky - Web page: https://patentgrep.com/patent/US11310833B2 ## CPC - H04W 56/0045: {compensating for timing error by altering transmission time} - H04W 56/005: {compensating for timing error by adjustment in the receiver} - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 74/0891: {for synchronized access} - H04W 74/0836: with 2-step access - H04W 74/0838: using contention-free random access [CFRA] - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine to initiate a random access channel (RACH) procedure with a base station (BS). The UE may determine, based at least in part on determining to initiate the RACH procedure, whether a timing alignment timer, associated with a timing alignment of the UE and the BS, is expired. The UE may initiate the RACH procedure using the timing alignment based at least in part on determining that the timing alignment timer is not expired. Numerous other aspects are provided. ## Claims ### Claim 1 A method of wireless communication performed by a user equipment (UE), comprising: determining, based at least in part on a beam failure associated with a serving beam associated with the UE, to initiate a random access channel (RACH) procedure with a base station (BS); initiating, based at least in part on receiving an indication of a timing alignment from the BS, a timing alignment timer associated with the timing alignment, wherein the timing alignment identifies a timing offset or a gap between a downlink and uplink of a wireless communication link between the UE and the BS; determining, based at least in part on determining to initiate the RACH procedure, whether the timing alignment timer is expired; and initiating the RACH procedure on a target beam, associated with the UE and different from the serving beam, using the timing alignment based at least in part on determining that the timing alignment timer is not expired. ### Claim 2 (depends on 1) The method of claim 1, wherein determining to initiate the RACH procedure with the BS comprises: determining to initiate the RACH procedure based at least in part on the beam failure and determining that the UE is not configured with a scheduling request resource. ### Claim 3 (depends on 1) The method of claim 1, wherein determining to initiate the RACH procedure with the BS comprises: determining to initiate the RACH procedure based at least in part on detecting the beam failure. ### Claim 4 (depends on 1) The method of claim 1, further comprising: selecting the target beam, from a plurality of candidate beams associated with the BS, based at least in part on the target beam satisfying one or more thresholds. ### Claim 5 (depends on 1) The method of claim 1, wherein the timing alignment is associated with the serving beam; and wherein initiating the RACH procedure on the target beam comprises: adjusting the timing alignment based at least in part on a second timing offset between the serving beam and the target beam. ### Claim 6 (depends on 5) The method of claim 5, wherein adjusting the timing alignment comprises: adjusting a downlink timing of the timing alignment based at least in part on the second timing offset. ### Claim 7 (depends on 5) The method of claim 5, wherein initiating the RACH procedure on the target beam comprises: transmitting a RACH preamble, in a msg1 communication or a msgA communication of the RACH procedure, using the adjusted timing alignment. ### Claim 8 (depends on 1) The method of claim 1, further comprising maintaining or resetting, based on determining whether the timing alignment timer is expired, the timing alignment, wherein initiating the RACH procedure on the target beam using the timing alignment is based at least in part on maintaining or resetting the timing alignment. ### Claim 9 A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors coupled to the memory, the one or more processors configured to: determine, based at least in part on a beam failure associated with a serving beam associated with the UE, to initiate a random access channel (RACH) procedure with a base station (BS); initiate, based at least in part on receiving an indication of a timing alignment from the BS, a timing alignment timer associated with the timing alignment, wherein the timing alignment identifies a timing offset or a gap between a downlink and uplink of a wireless communication link between the UE and the BS; determine, based at least in part on determining to initiate the RACH procedure, whether the timing alignment timer is expired; and initiate the RACH procedure on a target beam, associated with the UE and different from the serving beam, using the timing alignment based at least in part on determining that the timing alignment timer is not expired. ### Claim 10 (depends on 9) The UE of claim 9, wherein, to determine to initiate the RACH procedure with the BS, the one or more processors are to: determine to initiate the RACH procedure based at least in part on the beam failure and determining that the UE is not configured with a scheduling request resource. ### Claim 11 (depends on 9) The UE of claim 9, wherein, to determine to initiate the RACH procedure with the BS, the one or more processors are to: determine to initiate the RACH procedure based at least in part on detecting the beam failure. ### Claim 12 (depends on 9) The UE of claim 9, wherein the one or more processors are further configured to: select the target beam, from a plurality of candidate beams associated with the BS, based at least in part on the target beam satisfying one or more thresholds. ### Claim 13 (depends on 9) The UE of claim 9, wherein the timing alignment is associated with the serving beam; and wherein to initiate the RACH procedure on the target beam, are to: adjust the timing alignment based at least in part on a second timing offset between the serving beam and the target beam. ### Claim 14 (depends on 13) The UE of claim 13, wherein, to adjust the timing alignment, the one or more processors are to: adjust a downlink timing of the timing alignment based at least in part on the timing offset. ### Claim 15 (depends on 13) The UE of claim 13, wherein, to initiate the RACH procedure on the target beam, the one or more processors are to: transmit a RACH preamble, in a msg1 communication or a msgA communication of the RACH procedure, using the adjusted timing alignment. ### Claim 16 (depends on 9) The UE of claim 9, wherein the memory and the one or more processors are further configured to: maintain or reset, based on determining whether the timing alignment timer is expired, the timing alignment, wherein the one or more processors, when initiating the RACH procedure on the target beam, are to: initiate the RACH procedure on the target beam using the timing alignment is based at least in part on maintaining or resetting the timing alignment. ### Claim 17 A non-transitory computer-readable medium storing one or more instructions for wireless communication, the one or more instructions comprising: one or more instructions that, when executed by one or more processors of a user equipment (UE), cause the one or more processors to: determine, based at least in part on a beam failure associated with a serving beam associated with the UE, to initiate a random access channel (RACH) procedure with a base station (BS); initiate, based at least in part on receiving an indication of a timing alignment from the BS, a timing alignment timer associated with the timing alignment, wherein the timing alignment identifies a timing offset or a gap between a downlink and uplink of a wireless communication link between the UE and the BS; determine, based at least in part on determining to initiate the RACH procedure, whether the timing alignment timer is expired; and initiate on a target beam, associated with the UE and different from the serving beam, the RACH procedure using the timing alignment based at least in part on determining that the timing alignment timer is not expired. ### Claim 18 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the one or more instructions, that cause the one or more processors to determine to initiate the RACH procedure with the BS, cause the one or more processors to: determine to initiate the RACH procedure based at least in part on the beam failure and determining that the UE is not configured with a scheduling request resource. ### Claim 19 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the one or more instructions, that cause the one or more processors to determine to initiate the RACH procedure with the BS, cause the one or more processors to: determine to initiate the RACH procedure based at least in part on detecting the beam failure. ### Claim 20 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to: select the target beam, from a plurality of candidate beams associated with the BS, based at least in part on the target beam satisfying one or more thresholds. ### Claim 21 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the timing alignment is associated with the serving beam; and wherein the one or more instructions, that cause the one or more processors to initiate the RACH procedure on the target beam, cause the one or more processors to: adjust the timing alignment based at least in part on a second timing offset between the serving beam and the target beam. ### Claim 22 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein the one or more instructions, that cause the one or more processors to adjust the timing alignment, cause the one or more processors to: adjust a downlink timing of the timing alignment based at least in part on the timing offset. ### Claim 23 (depends on 21) The non-transitory computer-readable medium of claim 21, wherein the one or more instructions, that cause the one or more processors to initiate the RACH procedure on the target beam, cause the one or more processors to: transmit a RACH preamble, in a msg1 communication or a msgA communication of the RACH procedure, using the adjusted timing alignment. ### Claim 24 (depends on 17) The non-transitory computer-readable medium of claim 17, wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to: maintain or reset, based on determining whether the timing alignment timer is expired, the timing alignment, wherein the one or more instructions, that cause the one or more processors to initiate the RACH procedure on the target beam, cause the one or more processors to: initiate the RACH procedure on the target beam using the timing alignment is based at least in part on maintaining or resetting the timing alignment. ### Claim 25 An apparatus for wireless communication, comprising: means for determining to initiate a random access channel (RACH) procedure with a base station (BS); means for initiating, based at least in part on receiving an indication of a timing alignment from the BS, a timing alignment timer associated with the timing alignment, wherein the timing alignment identifies a timing offset or a gap between a downlink and uplink of a wireless communication link between the apparatus and the BS; means for determining, based at least in part on determining to initiate the RACH procedure based at least in part on a beam failure associated with a serving beam associated with the apparatus, whether the timing alignment timer is expired; and means for initiating the RACH procedure on a target beam, associated with the apparatus and different from the serving beam, using the timing alignment based at least in part on determining that the timing alignment timer is not expired. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein the means for determining to initiate the RACH procedure with the BS comprises: means for determining to initiate the RACH procedure based at least in part on the beam failure recover and determining that the apparatus is not configured with a scheduling request resource. ### Claim 27 (depends on 25) The apparatus of claim 25, wherein the means for determining to initiate the RACH procedure with the BS comprises: means for determining to initiate the RACH procedure based at least in part on detecting the beam failure. ### Claim 28 (depends on 25) The apparatus of claim 25, further comprising: means for selecting the target beam, from a plurality of candidate beams associated with the BS, based at least in part on the target beam satisfying one or more thresholds. ### Claim 29 (depends on 25) The apparatus of claim 25, wherein the timing alignment is associated with the serving beam; and wherein the means for initiating the RACH procedure on the target beam comprises: means for adjusting the timing alignment based at least in part on a second timing offset between the serving beam and the target beam. ### Claim 30 (depends on 25) The apparatus of claim 25, further comprising: means for maintaining or resetting, based on determining whether the timing alignment timer is expired, the timing alignment, wherein the means for initiating the RACH procedure on the target beam using the timing alignment is based at least in part on the means for maintaining or resetting the timing alignment.