# US 11,122,472 B2 · Method and system for beam tracking failure recovery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,122,472 B2 - Document ID: US11122472B2 - Status: Granted - Kind: B2 - Application number: 16/469,570 - Filed: 2018-03-22 - Published: 2020-03-12 - Granted: 2021-09-14 - Earliest claimed: 2017-03-24 - Assignees: Telefonaktiebolaget LM Ericsson (publ) - Applicants: Telefonaktiebolaget LM Ericsson (publ) - Inventors: Icaro Leonardo J. Da Silva - Web page: https://patentgrep.com/patent/US11122472B2 ## CPC - H04W 36/0061: {of neighbour cell information} - H04L 1/0026: {Transmission of channel quality indication} - 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 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 41/0668: by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure - H04W 16/28: using beam steering - H04W 24/08: Testing, {supervising or monitoring} using real traffic - H04W 36/0085: {Hand-off measurements} - H04W 36/06: Reselecting a communication resource in the serving access point - H04W 72/046: {the resource being in the space domain, e.g. beams} - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 76/19: Connection re-establishment - H04W 74/0833: Random access procedures, e.g. with 4-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) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract In some embodiments herein a wireless device for handling communication of the wireless device in a wireless communication network is provided. The wireless communication network comprises a radio network node configured to serve the wireless device in a serving cell. The wireless device is configured to perform a beam tracking of the serving cell for tracking one or more beams of the serving cell based on measured signal strength or measured signal quality, and to detect a beam failure process in the serving cell. The wireless device is further configured to, in response to detection of the beam failure process, trigger a beam recovery process associated with a DL beam for the serving cell, wherein the DL beam is selected based on the beam tracking performed prior to detecting the beam failure process. ## Claims ### Claim 1 A method performed by a wireless device for handling communication of the wireless device in a wireless communication network, wherein the wireless device is served by a radio network node in a serving cell, the method comprising: performing a beam tracking of the serving cell for tracking one or more beams of the serving cell based on measured signal strength or measured signal quality, wherein the beam tracking comprises collecting in the wireless device a snapshot and/or sample of a synchronization signal, SS, Block Burst or Burst Set; detecting a beam failure process in the serving cell; in response to detection of the beam failure process, triggering a beam recovery process associated with a downlink, DL, beam for the serving cell, wherein the DL beam is selected based on the beam tracking performed prior to detecting the beam failure process; and when a confirmation for the selected DL beam from the radio network node is lacking during a time window, transmitting a request to access another beam being a second best beam according to the performed beam tracking. ### Claim 2 (depends on 1) The method according to claim 1, wherein performing the beam tracking comprises performing measurements on reference signals for beams for the serving cell, and wherein the DL beam is selected based on the measured signal strength or measured signal quality on reference signals for respective beam. ### Claim 3 (depends on 1) The method according to claim 1, wherein the beam recovery process comprises: choosing a downlink reference signal in the DL beam. ### Claim 4 (depends on 3) The method according to claim 3, wherein the beam recovery process comprises: sending an uplink message to inform the radio network node of the DL beam of the chosen downlink reference signal. ### Claim 5 (depends on 1) The method according to claim 1, wherein the beam tracking further comprises collecting in the wireless device a channel state information-reference signal of the one or more beams. ### Claim 6 (depends on 1) The method according to claim 1, wherein detecting the beam failure process comprises detecting a physical downlink control channel, PDCCH, failure and/or a downlink beam failure. ### Claim 7 (depends on 1) The method according to claim 1, wherein the method comprises: receiving configuration data comprising a number of beams per cell to be possibly selected when beam failure is detected by the wireless device. ### Claim 8 A non-transitory computer-readable storage medium, having stored thereon a computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to: perform a beam tracking of the serving cell for tracking one or more beams of the serving cell based on measured signal strength or measured signal quality, wherein the beam tracking comprises collecting in the wireless device a snapshot and/or sample of a synchronization signal, SS, Block Burst or Burst Set; detect a beam failure process in the serving cell; in response to detection of the beam failure process, trigger a beam recovery process associated with a downlink, DL, beam for the serving cell, wherein the DL beam is selected based on the beam tracking performed prior to detecting the beam failure process; and when a confirmation for the selected DL beam from the radio network node is lacking during a time window, transmit a request to access another beam being a second best beam according to the performed beam tracking. ### Claim 9 A wireless device for handling communication of the wireless device in a wireless communication network, wherein the wireless communication network comprises a radio network node configured to serve the wireless device in a serving cell, and wherein the wireless device comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said wireless device is operative to: perform a beam tracking of the serving cell for tracking one or more beams of the serving cell based on measured signal strength or measured signal quality, wherein the beam tracking comprises collecting in the wireless device a snapshot and/or sample of a synchronization signal, SS, Block Burst or Burst Set; detect a beam failure process in the serving cell; in response to detection of the beam failure process, trigger a beam recovery process associated with a downlink, DL, beam for the serving cell, wherein the DL beam is selected based on the beam tracking performed prior to detecting the beam failure process; and when a confirmation for the selected DL beam from the radio network node is lacking during a time window, transmit a request to access another beam being a second best beam according to the performed beam tracking. ### Claim 10 (depends on 9) The wireless device according to claim 9, wherein the wireless device is operative to perform the beam tracking by performing measurements on reference signals for beams for the serving cell, and wherein the DL beam is selected based on the measured signal strength or measured signal quality on reference signals for respective beam. ### Claim 11 (depends on 9) The wireless device according to claim 9, wherein the beam recovery process comprises to choose a downlink reference signal in the DL beam. ### Claim 12 (depends on 11) The wireless device according to claim 11, wherein the beam recovery process comprises to send an uplink message to inform the radio network node of the DL beam of the chosen downlink reference signal. ### Claim 13 (depends on 9) The wireless device according to claim 9, wherein the beam tracking further comprises to collect in the wireless device a channel state information-reference signal of the one or more beams. ### Claim 14 (depends on 9) The wireless device according to claim 9, wherein the wireless device is operative to detect the beam failure process by detecting a physical downlink control channel, PDCCH, failure and/or a downlink beam failure. ### Claim 15 (depends on 9) The wireless device according to claim 9, wherein the wireless device is operative to receive configuration data comprising a number of beams per cell to be possibly selected per cell when beam failure is detected by the wireless device.