# US 2021/0344405 A1 · Method, device and computer readable medium for beam failure recovery for secondary cell > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344405 A1 - Document ID: US20210344405A1 - Status: Published application - Kind: A1 - Application number: 17/266,817 - Filed: 2018-08-09 - Published: 2021-11-04 - Earliest claimed: 2018-08-09 - Assignees: NEC Corporation - Applicants: NEC Corporation - Inventors: Fang YUAN; Lin LIANG; Gang WANG - Web page: https://patentgrep.com/patent/US20210344405A1 ## CPC - H04B 7/06964: {Re-selection of one or more beams after beam failure} - H04B 7/088: {using beam selection} - H04W 72/1263: Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows - H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W 76/19: Connection re-establishment - H04W 80/02: Data link layer protocols - H04W 72/21: in the uplink direction of a wireless link, i.e. towards the network - H04W 74/0838: using contention-free random access [CFRA] - H04B: TRANSMISSION - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Embodiments of the present disclosure relate to methods, devices and computer readable media for beam failure recovery for a secondary cell. In example embodiments, a method implemented in a terminal device includes in response to a beam failure on a secondary cell (Scell), transmitting a scheduling request to a network device; receiving, from the network device and on a primary cell (Pcell), a response indicating a resource allocated to the terminal device; transmitting, to the network device and using the allocated resource, a beam failure recovery request comprising a beam index of a beam selected from available beams on the Scell by the terminal device, to recover communication between the terminal device and the network device via the selected beam on the Scell. ## Claims ### Claim 1 A method implemented in a terminal device, comprising: in response to a beam failure on a secondary cell (Scell), transmitting a scheduling request to a network device; receiving, from the network device and on a primary cell (Pcell), a response indicating a resource allocated to the terminal device; transmitting, to the network device and using the allocated resource, a beam failure recovery request comprising a beam index of a beam selected from available beams on the Scell by the terminal device, to recover communication between the terminal device and the network device via the selected beam on the Scell. ### Claim 2 (depends on 1) The method of claim 1, wherein transmitting the scheduling request comprises transmitting a random access preamble on the Pcell, wherein receiving the response comprises receiving downlink control information with an uplink grant, and wherein transmitting the beam failure recovery request comprises transmitting the beam index and a Scell index of the Scell in media access control (MAC) control element (CE). ### Claim 3 (depends on 1) The method of claim 1, wherein transmitting the scheduling request comprises transmitting a random access preamble on the Scell, wherein receiving the response comprises receiving downlink control information with an uplink grant, and wherein transmitting the beam failure recovery request comprises transmitting the beam index in media access control (MAC) control element (CE). ### Claim 4 (depends on 1) The method of claim 1, wherein transmitting the scheduling request comprises transmitting the scheduling request on an uplink control channel of the Pcell, wherein receiving the response comprises receiving downlink control information with an uplink grant, and wherein transmitting the beam failure recovery request comprises transmitting the beam index and a Scell index of the Scell in media access control (MAC) control element (CE). ### Claim 5 (depends on 1) The method of claim 1, further comprising: in response to receiving from the network device downlink control information on reschedule of the beam failure recovery request, retransmitting the beam failure recovery request to the network device; and initiating a timer for monitoring a response to the beam failure recovery request. ### Claim 6 A method implemented in a terminal device, comprising: in response to a beam failure on a secondary cell (Scell), determining a random access preamble to be transmitted, the random access preamble indicating a Scell index of the Scell; transmitting the random access preamble to a network device; receiving, from the network device and on a primary cell (Pcell), downlink control information including a request for channel state information (CSI) reporting for the Scell; and transmitting, to the network device, a beam index of a beam selected from available beams on the Scell by the terminal device, to recover communication between the terminal device and the network device via the selected beam on the Scell. ### Claim 7 A method implemented in a terminal device, comprising: in response to a beam failure on a secondary cell (Scell), determining a random access preamble to be transmitted, the random access preamble indicating a beam index of a beam selected from available beams on the Scell by the terminal device; transmitting the random access preamble to a network device and on the Scell, to recover communication between the terminal device and the network device via the selected beam on the Scell. ### Claim 8 A method implemented in a terminal device, comprising: in response to a beam failure on a secondary cell (Scell), determining an uplink control channel of a primary cell (Pcell) to be used, based on resources of the uplink control channel and uplink control information to be transmitted on the uplink control channel; and transmitting, to a network device and on the uplink control channel, a beam failure recovery request along with the uplink control information, the beam failure recovery request comprising a Scell index of the Scell and a beam index of a beam selected from available beams on the Scell by the terminal device, to recover communication between the terminal device and the network device via the selected beam on the Scell. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the uplink control channel to be used comprising: determining a first number of physical resource blocks that are allocated to the uplink control channel; determining a second number of physical resource blocks to be used by the uplink control information; based on the first number and the second number, determining a third number of physical resource blocks that can be used to transmit the beam failure recovery request; and in response to the third number being equate to or greater than a threshold number, determining the uplink control channel as a channel to transmit the beam failure recovery request. ### Claim 10 (depends on 8) The method of claim 8, further comprising: after transmitting the beam failure recovery request on the uplink control channel, initiating a timer for monitoring a response to the beam failure recovery request; in response to the timer having expired and no response to beam failure recovery request being received, retransmitting the beam failure recovery request. ### Claim 11 A method implemented in a network device, comprising: receiving a scheduling request from a terminal device; transmitting, to the terminal device and on a primary cell (Pcell), a response indicating a resource allocated to the terminal device; receiving, from the terminal device and using the allocated resource, a beam failure recovery request comprising a beam index of a beam selected from available beams on a Scell by the terminal device, to communicate with the terminal device via the selected beam on the Scell. ### Claim 12 (depends on 11) The method of claim 11, wherein receiving the scheduling request comprising receiving a random access preamble on the Pcell, wherein transmitting the response comprises transmitting downlink control information with an uplink grant, and wherein receiving the beam failure recovery request comprises receiving the beam index and a Scell index of the Scell in media access control (MAC) control element (CE). ### Claim 13 (depends on 11) The method of claim 11, wherein receiving the scheduling request comprises receiving a random access preamble on the Scell, wherein transmitting the response comprises transmitting downlink control information with an uplink grant, and wherein receiving the beam failure recovery request comprises receiving the beam index in media access control (MAC) control element (CE). ### Claim 14 (depends on 11) The method of claim 11, wherein receiving the scheduling request comprises receiving the scheduling request on an uplink control channel of the Pcell, wherein transmitting the response comprises transmitting downlink control information with an uplink grant, and wherein receiving the beam failure recovery request comprises receiving the beam index and a Scell index of the Scell in media access control (MAC) control element (CE). ### Claim 15 (depends on 11) The method of claim 11, further comprising: transmitting, to the terminal device, a response to the beam failure recovery on the Scell. ### Claim 16 A method implemented in a network device, comprising: receiving a random access preamble from a terminal device, the random access preamble indicating a secondary cell (Scell) index of a Scell serving the terminal device; determining the Scell from the random access preamble; transmitting, to the terminal device and on a primary cell (Pcell) serving the terminal device, downlink control information including a request for channel state information (CSI) reporting for the Scell; and receiving, from the terminal device, a beam index of a beam selected from available beams on the Scell by the terminal device, to communicate with the terminal device via the selected beam on the Scell. ### Claim 17 A method implemented in a network device, comprising: receiving a random access preamble from a terminal device and on a secondary cell (Scell) serving the terminal device, the random access preamble indicating a beam index of of a beam selected from available beams on the Scell by the terminal device; and determining the beam index from the random access preamble, to communicate with the terminal device via the selected beam on the Scell. ### Claim 18 A method implemented in a network device, comprising: receiving, from a terminal device and on an uplink control channel of a primary cell (Pcell) serving the terminal device, a beam failure recovery request along with uplink control information; and obtaining, from the beam failure recovery request, a Scell index of a secondary cell (Scell) serving the terminal device and a beam index of a beam selected from available beams on the Scell by the terminal device, to communicate with the terminal device via the selected beam on the Scell. ### Claim 19 (depends on 1, 2, 3, 4, 5) A terminal device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to any of claims 1-5. ### Claim 20 (depends on 6) A terminal device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to claim 6. ### Claim 21 (depends on 7) A terminal device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to claim 7. ### Claim 22 (depends on 8, 9, 10) A terminal device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to any of claims 8-10. ### Claim 23 (depends on 11, 12, 13, 14, 15) A network device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to any of claims 11-15. ### Claim 24 (depends on 16) A network device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to claim 16. ### Claim 25 (depends on 17) A network device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to claim 17. ### Claim 26 (depends on 18) A network device, comprising: a processor; and a memory coupled to the processing unit and storing instructions thereon, the instructions, when executed by the processing unit, causing the device to perform the method according to claim 18. ### Claim 27 (depends on 1, 2, 3, 4, 5) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any of claims 1-5. ### Claim 28 (depends on 6) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to claim 6. ### Claim 29 (depends on 7) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to claim 7. ### Claim 30 (depends on 8, 9, 10) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any of claims 8-10. ### Claim 31 (depends on 11, 12, 13, 14, 15) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to any of claims 11-15. ### Claim 32 (depends on 16) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to claim 16. ### Claim 33 (depends on 17) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to claim 17. ### Claim 34 (depends on 18) A computer readable medium having instructions stored thereon, the instructions, when executed on at least one processor, causing the at least one processor to carry out the method according to claim 18.