# US 12,225,418 B2 · Method and apparatus for mobility management in wireless communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,418 B2 - Document ID: US12225418B2 - Status: Granted - Kind: B2 - Application number: 17/414,599 - Filed: 2019-12-27 - Published: 2022-02-17 - Granted: 2025-02-11 - Earliest claimed: 2018-12-28 - Assignees: LG Electronics Inc. - Applicants: LG Electronics Inc. - Inventors: Hongsuk Kim; Sunyoung Lee; Youngdae Lee; Yejee Lee - Web page: https://patentgrep.com/patent/US12225418B2 ## CPC - H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports} - H04W 36/362: {Conditional handover} - H04W 36/0044: {of quality context information} - H04W 36/0061: {of neighbour cell information} - H04W 76/27: Transitions between radio resource control [RRC] states - H04W 36/249: {according to timing information} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present disclosure relates to mobility management wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device in a wireless communication system comprises: receiving, from a source cell, a handover command comprising a handover validity timer; performing a handover attempt to a target cell while the handover validity timer is running; and transmitting, to the source cell, a report message comprising cell information including target cell information for the target cell upon an expiration of the handover validity timer. ## Claims ### Claim 1 A method performed by a user equipment (UE) in a wireless communication system, the method comprising: receiving, from a network, a configuration for conditional mobility, wherein the configuration for conditional mobility comprises a corresponding mobility condition for each of multiple candidate cells; evaluating mobility conditions for the multiple candidate cells; based on the evaluation of a mobility condition for a target cell among the multiple candidate cells, starting a timer for a mobility attempt to the target cell; performing the mobility attempt to the target cell while the timer is running; and transmitting, to the network, report information based on a failure of the mobility attempt to the target cell, the failure of the mobility attempt to the target cell being related to an expiry of the timer, wherein the report information is transmitted based on an instruction received from the network, wherein the report information comprises candidate cell information for all of the multiple candidate cells based on the instruction, and wherein the report information comprises: a cell identity of the target cell that has failed the mobility attempt; a cell identity of at least one neighbor cell among the multiple candidate cells; and information informing that a mobility condition for the at least one neighbor cell has been fulfilled at a moment of the failure of the mobility attempt. ### Claim 2 (depends on 1) The method of claim 1, wherein the expiry of the timer results in the failure of the mobility attempt to the target cell, and wherein the timer starts running in response to performing the mobility attempt to the target cell. ### Claim 3 (depends on 1) The method of claim 1, further comprising: performing a measurement on the at least one neighbor cell during the mobility attempt to the target cell; and obtaining a result of the measurement on the at least one neighbor cell. ### Claim 4 (depends on 1) The method of claim 1, wherein the report information further comprises: at least one of a result of a measurement on the target cell; a result of a measurement on the at least one neighbor cell; or a time-to-trigger (TTT) counting status of the at least one neighbor cell. ### Claim 5 (depends on 1) The method of claim 1, further comprising: after transmitting the report information to the network, receiving, from the network, a mobility command for another target cell; and performing a mobility attempt to the other target cell. ### Claim 6 (depends on 1) The method of claim 1, wherein the configuration for conditional mobility comprises reporting conditions for the multiple candidate cells, further comprising: identifying a candidate cell for which a reporting condition is satisfied among the multiple candidate cells, wherein the report information comprises candidate cell information for the candidate cell, and wherein the report information excludes candidate cell information for other candidate cells for which a reporting condition is not satisfied among the multiple candidate cells. ### Claim 7 (depends on 6) The method of claim 6, wherein the reporting conditions comprise mobility events for multiple candidate cells, and wherein the identifying of the candidate cell comprises identifying the candidate cell for which an entering condition for a mobility event is satisfied among the multiple candidate cells. ### Claim 8 (depends on 6) The method of claim 6, wherein the reporting conditions comprise time-to-trigger (TTT) thresholds for the multiple candidate cells, and wherein the identifying of the candidate cell comprises: determining a time period during which an entering condition for a mobility event is satisfied for each of the multiple candidate cells; and identifying the candidate cell for which the time period is greater than or equal to a TTT threshold among the multiple candidate cells. ### Claim 9 (depends on 6) The method of claim 6, wherein the reporting conditions comprise offsets for the multiple candidate cells, and wherein the identifying of the candidate cell comprises identifying the candidate cell for which a signal quality is better than that for a source cell by more than or equal to an offset among the multiple candidate cells. ### Claim 10 (depends on 6) The method of claim 6, wherein the reporting conditions comprise thresholds for the multiple candidate cells, and wherein the identifying of the candidate cell comprises identifying the candidate cell for which a signal quality is better than a threshold among the multiple candidate cells. ### Claim 11 (depends on 1) The method of claim 1, wherein the UE is in communication with at least one of a mobile device, a network, or autonomous vehicles other than the UE. ### Claim 12 A user equipment (UE) configured to operate in a wireless communication system, the UE comprising: a memory; a transceiver; and at least one processor operatively coupled to the memory and the transceiver, wherein the memory stores instructions that, based on being executed by the at least one processor, perform operations comprising: receiving, from a network, a configuration for conditional mobility, wherein the configuration for conditional mobility comprises a corresponding mobility condition for each of multiple candidate cells; evaluating mobility conditions for the multiple candidate cells based on the evaluation of a mobility condition for a target cell among the multiple candidate cells, starting a timer for a mobility attempt to the target cell; performing the mobility attempt to the target cell while the timer is running; and transmitting, to the network, report information based on a failure of the mobility attempt to the target cell, the failure of the mobility attempt to the target cell being related to an expiry of the timer, wherein the report information is transmitted based on an instruction received from the network, wherein the report information comprises candidate cell information for all of the multiple candidate cells based on the instruction, and wherein the report information comprises: a cell identity of the target cell that has failed the mobility attempt; a cell identity of at least one neighbor cell among the multiple candidate cells; and information informing that a mobility condition for the at least one neighbor cell has been fulfilled at a moment of the failure of the mobility attempt. ### Claim 13 A non-transitory computer-readable medium having recorded thereon a program for performing each step of a method on a computer, the method comprising: receiving, from a network, a configuration for conditional mobility, wherein the configuration for conditional mobility comprises a corresponding mobility condition for each of multiple candidate cells; evaluating mobility conditions for the multiple candidate cells; based on the evaluation of a mobility condition for a target cell among the multiple candidate cells, starting a timer for a mobility attempt to the target cell; performing the mobility attempt to the target cell while the timer is running; and transmitting, to the network, report information based on a failure of the mobility attempt to the target cell, the failure of the mobility attempt to the target cell being related to an expiry of the timer, wherein the report information is transmitted based on an instruction received from the network, wherein the report information comprises candidate cell information for all of the multiple candidate cells based on the instruction, and wherein the report information comprises: a cell identity of the target cell that has failed the mobility attempt; a cell identity of at least one neighbor cell among the multiple candidate cells; and information informing that a mobility condition for the at least one neighbor cell has been fulfilled at a moment of the failure of the mobility attempt.