# US 12,120,571 B2 · User equipment-triggered lower layer-based handover > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,571 B2 - Document ID: US12120571B2 - Status: Granted - Kind: B2 - Application number: 17/593,425 - Filed: 2020-05-15 - Published: 2022-09-22 - Granted: 2024-10-15 - Earliest claimed: 2020-05-15 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Yushu Zhang; Chunhai Yao; Dawei Zhang; Fangli Xu; Haijing Hu; Haitong Sun; Wei Zeng - Web page: https://patentgrep.com/patent/US12120571B2 ## CPC - H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports} - H04W 36/0016: {Hand-off preparation specially adapted for end-to-end data sessions} - H04W 36/0064: {of control information between different access points} - H04W 36/30: by measured or perceived connection quality data - H04W 36/304: {due to measured or perceived resources with higher communication quality} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Performing a UE-triggered lower layer-based handover may include, based on measurements associated with both a source gNB and a target gNB, determining that a UE-triggered handover utilizing layer 1 or layer 2 is to be performed. First uplink resources configured by the source gNB for a dedicated scheduling request may be determined. The dedicated scheduling request may be generated at the UE to request second uplink resources from the gNB for a physical uplink shared channel (PUSCH) a handover request in a media access control (MAC) control element (CE). The handover request carried by the MAC CE for the source gNB may be generated. In response to the handover request, a handover command from the source gNB associated with performing a handover procedure from the source gNB to the target gNB may be processed. ## Claims ### Claim 1 An apparatus of a user equipment (UE), comprising: one or more processors configured to: based on measurements associated with both a source base station and a target base station, determine that a UE-triggered handover utilizing layer 1 or layer 2 is to be performed; determine first uplink resources configured by the source base station for a dedicated scheduling request; generate, at the UE, the dedicated scheduling request to request second uplink resources from the source base station for a handover request in a media access control (MAC) control element (CE); generate the handover request, the handover request to be carried by the MAC CE to the source base station; transmit the handover request to the source base station in the MAC CE; monitor for a handover command received from the source base station in response to the handover request, wherein the handover command is associated with performing a handover procedure from the source base station to the target base station, and wherein the monitoring comprises generating a timer associated with the generated handover request, wherein expiration of the timer before receiving the handover command from the source base station causes the UE to re-generate the handover request; and process the handover command received from the source base station; and a memory configured to store information associated with performing a UE-triggered lower layer-based handover. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein a duration of the timer is configured by radio resource control (RRC) signaling. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the source base station configures a maximum number of handover request re-generations. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the handover command is carried by a MAC CE or a downlink control information (DCI). ### Claim 5 (depends on 1) The apparatus of claim 1, wherein at least one of a dedicated search space and a control resource set (CORESET) is used to receive the handover command. ### Claim 6 A computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a processor of a user equipment (UE) configured to perform a UE-triggered lower layer-based handover, cause the processor to: based on measurements associated with both a source base station and a target base station, determine that a UE-triggered handover utilizing layer 1 or layer 2 is to be performed; determine first uplink resources configured by the source base station for a dedicated scheduling request; generate, at the UE, the dedicated scheduling request to request second uplink resources from the source base station for a handover request in a media access control (MAC) control element (CE); generate the handover request, the handover request to be carried by the MAC CE to the source base station; transmit the handover request to the source base station in the MAC CE; monitor for a handover command received from the source base station in response to the handover request, wherein the handover command is associated with performing a handover procedure from the source base station to the target base station, and wherein the monitoring comprises generating a timer associated with the generated handover request, wherein expiration of the timer before receiving the handover command from the source base station causes the UE to re-generate the handover request; and process the handover command received from the source base station. ### Claim 7 (depends on 6) The computer-readable storage medium of claim 6, wherein a duration of the timer is configured by radio resource control (RRC) signaling. ### Claim 8 (depends on 7) The computer-readable storage medium of claim 7, wherein the source base station configures a maximum number of handover request re-generations. ### Claim 9 (depends on 6) The computer-readable storage medium of claim 6, wherein the handover command is carried by a MAC CE or a downlink control information (DCI). ### Claim 10 (depends on 6) The computer-readable storage medium of claim 6, wherein at least one of a dedicated search space and a control resource set (CORESET) is used to receive the handover command. ### Claim 11 A method for performing a UE-triggered lower layer-based handover, the method comprising: based on measurements associated with both a source base station and a target base station, determining that a UE-triggered handover utilizing layer 1 or layer 2 is to be performed; determining first uplink resources configured by the source base station for a dedicated scheduling request; generating, at the UE, the dedicated scheduling request to request second uplink resources from the source base station for a handover request in a media access control (MAC) control element (CE); generating the handover request, the handover request to be carried by the MAC CE to the source base station; transmitting the handover request to the source base station in the MAC CE; monitoring for a handover command received from the source base station in response to the handover request, wherein the handover command is associated with performing a handover procedure from the source base station to the target base station, and wherein the monitoring comprises generating a timer associated with the generated handover request, wherein expiration of the timer before receiving the handover command from the source base station causes the UE to re-generate the handover request; and processing the handover command received from the source base station. ### Claim 12 (depends on 11) The method of claim 11, wherein a duration of the timer is configured by radio resource control (RRC) signaling. ### Claim 13 (depends on 12) The method of claim 12, wherein the source base station configures a maximum number of handover request re-generations. ### Claim 14 (depends on 11) The method of claim 11, wherein the handover command is carried by a MAC CE or a downlink control information (DCI).