# US 11,121,758 B2 · Link recovery procedure enhancements > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,121,758 B2 - Document ID: US11121758B2 - Status: Granted - Kind: B2 - Application number: 16/737,697 - Filed: 2020-01-08 - Published: 2020-07-16 - Granted: 2021-09-14 - Earliest claimed: 2019-01-10 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Kiran Venugopal; Jung Ho Ryu; Makesh Pravin John Wilson; Tao Luo; Tianyang Bai - Web page: https://patentgrep.com/patent/US11121758B2 ## CPC - H04B 7/06964: {Re-selection of one or more beams after beam failure} - H04B 7/088: {using beam selection} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports} - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 76/11: Allocation or use of connection identifiers - H04W 76/19: Connection re-establishment - H04W 80/02: Data link layer protocols - 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] - 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 Certain aspects of the present disclosure provide techniques and apparatus for radio link recovery procedure enhancements in wireless communication systems. In some cases, radio link recovery may be enhanced (e.g., sped up and network congestion reduced) by allowing a user equipment (UE) to use an additional secondary cell (SCell) serving the UE to assist in beam recovery when a layer one (L1) event is detected on a primary cell (PCell) or primary secondary cell (PSCell) of the UE. ## Claims ### Claim 1 A method of wireless communication by a user equipment (UE), comprising: detecting a layer one (L1) event associated with at least one of a primary cell (PCell) serving the UE or a primary secondary cell (PSCell) serving the UE; triggering, in response to detecting the L1 event, a beam recovery procedure for at least one of the PCell or the PSCell, wherein triggering the beam recovery procedure includes transmitting a reconfiguration request via an additional secondary cell (SCell) to reconfigure at least one beam for at least one of the PCell or the PSCell; receiving request information via the additional SCell requesting identification information of the at least one beam to reconfigure; transmitting the requested identification information of the at least one beam; receiving, in response to transmitting the requested identification information, reconfiguration information for the at least one beam; and communicating, based on the reconfiguration information, with at least one of the PCell or the PSCell using the at least one beam. ### Claim 2 (depends on 1) The method of claim 1, wherein: the L1 event comprises a beam failure associated with at least one of the PCell or the PSCell; and detecting the beam failure associated with at least one of the PCell or the PSCell comprises detecting that a reference signal measurement of one or more beams associated with at least one of the PCell or the PSCell falls below a threshold. ### Claim 3 (depends on 1) The method of claim 1, wherein transmitting the reconfiguration request comprises transmitting the reconfiguration request via the additional SCell in a dedicated scheduling request. ### Claim 4 (depends on 1) The method of claim 1, wherein transmitting the reconfiguration request comprises transmitting the reconfiguration request via the additional SCell using a physical uplink control channel (PUCCH) group different from a PUCCH group associated with the L1 event. ### Claim 5 (depends on 1) The method of claim 1, further comprising, repeating transmission of the reconfiguration request via the additional SCell for a threshold number of times if a response to the reconfiguration request is not received within a defined time window. ### Claim 6 (depends on 1) The method of claim 1, further comprising receiving the request information via the additional SCell in an uplink grant. ### Claim 7 (depends on 6) The method of claim 6, further comprising, based on information in the uplink grant, transmitting the requested identification information of the at least one beam via the additional SCell in at least one of: a media access control control element (MAC-CE) on a physical uplink shared channel (PUSCH); or a message on a physical uplink control channel (PUCCH) of the additional SCell. ### Claim 8 (depends on 1) The method of claim 1, wherein the request information includes an indication of radio access channel (RACH) resources for an on-demand RACH. ### Claim 9 (depends on 1) The method of claim 1, wherein transmitting the requested identification information comprising transmitting a RACH message on the RACH of the at least one beam using the indicated RACH resources. ### Claim 10 (depends on 1) The method of claim 1, wherein the reconfiguration information is received in downlink control information scrambled with a cell radio network temporary identifier (C-RNTI) associated with the UE on a physical downlink control channel (PDCCH) of at least one of the PCell or the PSCell. ### Claim 11 A method of wireless communication by a base station, comprising: receiving, from a user equipment (UE) served by at least one of a primary cell (PCell) or a primary secondary cell (PSCell), a reconfiguration request to reconfigure at least one beam for at least one of the PCell or the PSCell in response to a layer one (L1) event at the UE associated with at least one of the PCell or the PSCell, wherein the reconfiguration request is received via an additional secondary cell (SCell) serving the UE; transmitting, to the UE, request information requesting identification information of the at least one beam to reconfigure; receiving, from the UE, the requested identification information of the at least one beam; and transmitting, in response to receiving the requested identification information, reconfiguration information for the at least one beam. ### Claim 12 (depends on 11) The method of claim 11, wherein receiving the reconfiguration request comprises receiving the reconfiguration request in a dedicated scheduling request. ### Claim 13 (depends on 11) The method of claim 11, wherein receiving the reconfiguration request comprises receiving the reconfiguration request using a physical uplink control channel (PUCCH) group different from a PUCCH group associated with the L1 event. ### Claim 14 (depends on 11) The method of claim 11, further comprising transmitting the request information in an uplink grant. ### Claim 15 (depends on 14) The method of claim 14, further comprising, based on information in the uplink grant, receiving the requested identification information of the at least one beam in at least one of: a media access control control element (MAC-CE) on a physical uplink shared channel (PUSCH); or a message on a physical uplink control channel (PUCCH) of the SCell. ### Claim 16 (depends on 11) The method of claim 11, wherein the request information includes an indication of radio access channel (RACH) resources for an on-demand RACH of least one of the PCell or the PSCell. ### Claim 17 (depends on 16) The method of claim 16, wherein receiving the requested identification information comprises receiving, based on the indicated RACH resources, the requested identification information in a RACH message on the on-demand RACH of at least one of the PCell or the PScell. ### Claim 18 (depends on 17) The method of claim 17, wherein transmitting the reconfiguration information comprises transmitting downlink control information scrambled with a cell radio network temporary identifier (C-RNTI) on a physical downlink control channel (PDCCH) via at least one of the PCell or the PSCell. ### Claim 19 An apparatus for wireless communication by a user equipment (UE), comprising: at least one processor configured to: detect a layer one (L1) event associated with at least one of a primary cell (PCell) serving the UE or a primary secondary cell (PSCell) serving the UE; trigger, in response to detecting the L1 event, a beam recovery procedure for at least one of the PCell or the PSCell, wherein triggering the beam recovery procedure includes transmitting a reconfiguration request via an additional secondary cell (SCell) to reconfigure at least one beam for at least one of the PCell or the PSCell; receive request information via the additional SCell requesting identification information of the at least one beam to reconfigure; transmit the requested identification information of the at least one beam; receive, in response to transmitting the requested identification information, reconfiguration information for the at least one beam; and communicate, based on the reconfiguration information, with at least one of the PCell or the PSCell using the at least one beam; and a memory coupled with the at least one processor. ### Claim 20 (depends on 19) The apparatus of claim 19, wherein: the L1 event comprises a beam failure associated with at least one of the PCell or the PSCell; and the at least one processor is configured to detect the beam failure associated with at least one of the PCell or the PSCell by detecting that a reference signal measurement of one or more beams associated with at least one of the PCell or the PSCell falls below a threshold. ### Claim 21 (depends on 19) The apparatus of claim 19, wherein the at least one processor is configured to transmit the reconfiguration request by transmitting the reconfiguration request via the additional SCell in a dedicated scheduling request. ### Claim 22 (depends on 19) The apparatus of claim 19, wherein the at least one processor is configured to transmit the reconfiguration request by transmitting the reconfiguration request via the additional SCell using a physical uplink control channel (PUCCH) group different from a PUCCH group associated with the L1 event. ### Claim 23 (depends on 19) The apparatus of claim 19, wherein the at least one processor is further configured to repeat transmission of the reconfiguration request via the additional SCell for a threshold number of times if a response to the reconfiguration request is not received within a defined time window. ### Claim 24 (depends on 19) The apparatus of claim 19, wherein the at least one processor is further configured to: receive the request information via the additional SCell in an uplink grant; transmit, based on information in the uplink grant, the requested identification information of the at least one beam via the additional SCell in at least one of: a media access control control element (MAC-CE) on a physical uplink shared channel (PUSCH); or a message on a physical uplink control channel (PUCCH) of the additional SCell. ### Claim 25 An apparatus for wireless communication by a base station of an secondary cell, comprising: at least one processor configured to: receive, from a user equipment (UE) served by at least one of a primary cell (PCell) and or a primary secondary cell (PSCell), a reconfiguration request to reconfigure at least one beam for at least one of the PCell or the PSCell in response to a layer one (L1) event at the UE associated with at least one of the PCell or the PSCell, wherein the reconfiguration request is received via an additional secondary cell (SCell) serving the UE; transmit, to the UE, request information requesting identification information of the at least one beam to reconfigure; receive, from the UE, the requested identification information of the at least one beam; and transmit, in response to receiving the requested identification information, reconfiguration information for the at least one beam; and a memory coupled with the at least one processor. ### Claim 26 (depends on 25) The apparatus of claim 25, wherein receiving the reconfiguration request comprises receiving the reconfiguration request in a dedicated scheduling request. ### Claim 27 (depends on 25) The apparatus of claim 25, wherein receiving the reconfiguration request comprises receiving the reconfiguration request using a physical uplink control channel (PUCCH) group different from a PUCCH group associated with the L1 event. ### Claim 28 (depends on 25) The apparatus of claim 25, further comprising transmitting the request information in an uplink grant. ### Claim 29 (depends on 28) The apparatus of claim 28, further comprising, based on information in the uplink grant, receiving the requested identification information of the at least one beam in at least one of: a media access control control element (MAC-CE) on a physical uplink shared channel (PUSCH); or a message on a physical uplink control channel (PUCCH) of the SCell. ### Claim 30 (depends on 25) The apparatus of claim 25, wherein: the request information includes an indication of radio access channel (RACH) resources for an on-demand RACH of least one of the PCell or the PSCell; receiving the requested identification information comprises receiving, based on the indicated RACH resources, the requested identification information in a RACH message on the on-demand RACH of at least one of the PCell or the PScell; and transmitting the reconfiguration information comprises transmitting downlink control information scrambled with a cell radio network temporary identifier (C-RNTI) on a physical downlink control channel (PDCCH) via at least one of the PCell or the PSCell.