# US 12,225,424 B2 · Link failure report transmission method and apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,424 B2 - Document ID: US12225424B2 - Status: Granted - Kind: B2 - Application number: 17/651,168 - Filed: 2022-02-15 - Published: 2022-06-02 - Granted: 2025-02-11 - Earliest claimed: 2019-08-16 - Assignees: Huawei Technologies Co., Ltd. - Applicants: Huawei Technologies Co., Ltd. - Inventors: Xiaoli Shi; Henrik Olofsson; Hongzhuo Zhang; Rui Wang - Web page: https://patentgrep.com/patent/US12225424B2 ## CPC - H04W 36/305: {Handover due to radio link failure (control signalling for hand-off failure H04W36/0079)} - H04W 76/19: Connection re-establishment - H04W 24/02: Arrangements for optimising operational condition - H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports} - H04W 36/0079: {in case of hand-off failure or rejection} - H04W 36/00835: {Determination of neighbour cell lists} - H04W 36/00837: {Determination of triggering parameters for hand-off} - H04W 36/087: {between radio units of access points} - H04W 36/00698: {using different RATs} - H04W 36/00838: {Resource reservation for handover} - H04W 76/15: Setup of multiple wireless link connections - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A link failure report transmission method and apparatus are provided. When a link between a terminal and a first radio access network device fails, and a master radio access network device of the first radio access network device is handed over, the terminal sends a first link failure report to a second radio access network device, so that the second radio access network device forwards the first link failure report to a third radio access network device, and the third radio access network device sends the first link failure report to the first radio access network device. In this way, the first radio access network device can perform parameter adjustment based on the first link failure report. ## Claims ### Claim 1 A method comprising: sending, by a terminal, a first link failure report to a second radio access network device that is to serve the terminal, wherein the first link failure report indicates that a link between the terminal and a first radio access network device fails, and the first radio access network device is a secondary radio access network device of a third radio access network device; and wherein sending, by the terminal, the first link failure report to the second radio access network device comprises: sending, by the terminal, the first link failure report to the second radio access network device when the terminal is successfully handed over from the third radio access network device to a fourth radio access network device and a link between the terminal and the fourth radio access network device fails within a preset time interval. ### Claim 2 (depends on 1) The method according to claim 1, wherein sending, by the terminal, the first link failure report to the second radio access network device further comprises: sending, by the terminal, the first link failure report to the second radio access network device when the terminal is successfully handed over from the third radio access network device to the second radio access network device. ### Claim 3 (depends on 1) The method according to claim 1, wherein sending, by the terminal, the first link failure report to the second radio access network device further comprises: sending, by the terminal, the first link failure report to the second radio access network device when the terminal successfully reestablishes a connection to the second radio access network device. ### Claim 4 (depends on 1) The method according to claim 1, wherein the second radio access network device and the third radio access network device are a same access network device. ### Claim 5 (depends on 1) The method according to claim 1, wherein the method further comprises: sending, by the terminal, a second link failure report to the second radio access network device, wherein the second link failure report indicates that the link between the terminal and the fourth radio access network device fails. ### Claim 6 (depends on 1) The method according to claim 1, wherein sending, by the terminal, the first link failure report to the second radio access network device further comprises: sending, by the terminal, the first link failure report to the second radio access network device when the terminal fails to be handed over from the third radio access network device to the fourth radio access network device. ### Claim 7 (depends on 1) The method according to claim 1, wherein the first link failure report comprises at least one of the following: cell information of a second cell, wherein the second cell is within coverage of the first radio access network device, and a link failure occurs between the terminal and the second cell; a type of the link failure that occurs in the second cell; cell information of a cell covered by a master access network device corresponding to the second cell; a time interval between a moment at which the link between the terminal and the first radio access network device fails and a moment at which the terminal is handed over from the third radio access network device to the second radio access network device; an identifier of the terminal; location information of the terminal; a result of measurement between the terminal and each primary cell in a master cell group; or a result of measurement between the terminal and each secondary cell in a secondary cell group. ### Claim 8 An apparatus comprising: at least one processor; and a non-transitory memory coupled to the at least one processor, the memory comprising instructions that, when executed by the at least one processor, cause the apparatus to: send a first link failure report to a second radio access network device that is to serve the apparatus, wherein the first link failure report indicates that a link between the apparatus and a first radio access network device fails, and the first radio access network device is a secondary radio access network device of a third radio access network device; and wherein sending the first link failure report to the second radio access network device that is to serve the apparatus comprises: sending the first link failure report to the second radio access network device when the apparatus is successfully handed over from the third radio access network device to a fourth radio access network device and a link between the apparatus and the fourth radio access network device fails within a preset time interval. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein the instructions, when executed by the at least one processor, cause the apparatus further to: send the first link failure report to the second radio access network device when the apparatus is successfully handed over from the third radio access network device to the second radio access network device. ### Claim 10 (depends on 8) The apparatus according to claim 8, wherein the instructions, when executed by the at least one processor, cause the apparatus further to: send the first link failure report to the second radio access network device when the apparatus successfully reestablishes a connection to the second radio access network device. ### Claim 11 (depends on 8) The apparatus according to claim 8, wherein the second radio access network device and the third radio access network device are a same access network device. ### Claim 12 (depends on 8) The apparatus according to claim 8, wherein the instructions, when executed by the at least one processor, cause the apparatus further to: send a second link failure report to the second radio access network device, wherein the second link failure report indicates that the link between the apparatus and the fourth radio access network device fails. ### Claim 13 (depends on 8) The apparatus according to claim 8, wherein the instructions, when executed by the at least one processor, cause the apparatus further to: send the first link failure report to the second radio access network device when the apparatus fails to be handed over from the third radio access network device to the fourth radio access network device. ### Claim 14 (depends on 8) The apparatus according to claim 8, wherein the first link failure report comprises at least one of the following: cell information of a second cell, wherein the second cell is within coverage of the first radio access network device, and a link failure occurs between the apparatus and the second cell; a type of the link failure that occurs in the second cell; cell information of a cell covered by a master access network device corresponding to the second cell; a time interval between a moment at which the link between the apparatus and the first radio access network device fails and a moment at which the apparatus is handed over from the third radio access network device to the second radio access network device; an identifier of the apparatus; location information of the apparatus; a result of measurement between the apparatus and each primary cell in a master cell group; or a result of measurement between the apparatus and each secondary cell in a secondary cell group. ### Claim 15 (depends on 14) The apparatus according to claim 14, wherein the first link failure report further comprises at least one of following: a time interval between a moment at which a handover command is received by the apparatus and the moment at which the link between the apparatus and the first radio access network device fails, or a time interval between the moment at which the handover command is received and the moment at which the apparatus is handed over from the third radio access network device to the second radio access network device. ### Claim 16 An apparatus comprising: at least one processor; and a non-transitory memory coupled to the at least one processor, the memory comprising instructions that, when executed by the at least one processor, cause the apparatus to: receive a first link failure report from a terminal to be served by the apparatus, wherein the first link failure report indicates that a link between the terminal and a first radio access network device fails, and the first radio access network device is a secondary access network device of a third radio access network device; send the first link failure report to the third radio access network device; and receive a second link failure report from the terminal, wherein the second link failure report indicates that a link between the terminal and a fourth radio access network device fails. ### Claim 17 (depends on 16) The apparatus according to claim 16, wherein the first link failure report and the second link failure report are carried in one message. ### Claim 18 (depends on 16) The apparatus according to claim 16, wherein the second link failure report comprises at least one of following: cell information of a first cell, wherein the first cell is within coverage of the fourth radio access network device, and a link failure occurs between the terminal and the first cell; a type of the link failure that occurs in the first cell; cell information of a primary cell of a cell in which a connection failure occurs or cell information of a cell in which a handover command is received for the last time; cell information of a cell that is served by a radio access network device and in which the terminal successfully reestablishes a connection; a time interval between a moment at which the link between the terminal and the first radio access network device fails and a moment at which the link between the terminal and the fourth radio access network device fails; a time interval between the moment at which the link between the terminal and the fourth radio access network device fails and a moment at which a link between the terminal and the apparatus is successfully established; a time interval between a moment at which the handover command is received and the moment at which the link between the terminal and the fourth radio access network device fails; an identifier of the terminal; or a result of measurement between a neighboring cell of the first cell and the terminal. ### Claim 19 (depends on 16) The apparatus according to claim 16, wherein the first link failure report comprises at least one of the following: cell information of a second cell, wherein the second cell is within coverage of the first radio access network device, and a link failure occurs between the terminal and the second cell; a type of the link failure that occurs in the second cell; cell information of a cell covered by a master access network device corresponding to the second cell; a time interval between a moment at which the link between the terminal and the first radio access network device fails and a moment at which the terminal is handed over from the third radio access network device to the apparatus; an identifier of the terminal; location information of the terminal; a result of measurement between the terminal and each primary cell in a master cell group; or a result of measurement between the terminal and each secondary cell in a secondary cell group. ### Claim 20 (depends on 19) The apparatus according to claim 19, wherein the first link failure report further comprises at least one of following: a time interval between a moment at which a handover command is received by the terminal and the moment at which the link between the terminal and the first radio access network device fails, or a time interval between the moment at which the handover command is received and the moment at which the terminal is handed over from the third radio access network device to the apparatus.