# US 2026/0101410 A1 · Protocol Handling During Mobility > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0101410 A1 - Document ID: US20260101410A1 - Status: Published application - Kind: A1 - Application number: 19/417,849 - Filed: 2025-12-12 - Published: 2026-04-09 - Earliest claimed: 2023-09-28 - Assignees: Ofinno, LLC - Applicants: Ofinno, LLC - Inventors: Fasil Abdul Latheef; Taehun Kim; Esmael Hejazi Dinan; Kyungmin Park; Hyoungsuk Jeon - Web page: https://patentgrep.com/patent/US20260101410A1 ## CPC - H04W 36/0055: {Transmission or use of information for re-establishing the radio link} - H04W 76/27: Transitions between radio resource control [RRC] states - H04W 36/0064: {of control information between different access points} - H04W 76/19: Connection re-establishment - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A wireless device performs a layer 1 and/or layer 2 (L1/L2) triggered mobility (LTM) cell switch from a cell of a first base station to a candidate cell of a second base station. The LTM cell switch comprises a packet data convergence protocol (PDCP) reestablishment based on a value of a first identifier (ID) of the cell being different from a value of a second ID of the candidate cell. The wireless device transmits, to the second base station via the candidate cell, a radio resource control (RRC) reconfiguration complete message. ## Claims ### Claim 1 A method comprising: performing, by a wireless device, a layer 1 and/or layer 2 (L1/L2) triggered mobility (LTM) cell switch from a cell of a first base station to a candidate cell of a second base station, wherein the LTM cell switch comprises a packet data convergence protocol (PDCP) reestablishment based on a value of a first identifier (ID) of the cell being different from a value of a second ID of the candidate cell; and transmitting, to the second base station via the candidate cell, a radio resource control (RRC) reconfiguration complete message. ### Claim 2 (depends on 1) The method of claim 1, further comprising receiving, from the first base station, one or more RRC messages indicating: a configuration of the candidate cell for LTM; the first ID of the cell; and the second ID of the candidate cell. ### Claim 3 (depends on 1) The method of claim 1, further comprising receiving a medium access control control element (MAC CE) indicating the LTM cell switch from the cell of the first base station to the candidate cell of the second base station. ### Claim 4 (depends on 1) The method of claim 1, wherein the LTM cell switch further comprises: an RLC reestablishment; and a MAC reset. ### Claim 5 (depends on 1) The method of claim 1, wherein: the first ID is for the PDCP reestablishment of the wireless device; and the second ID is for the PDCP reestablishment of the wireless device. ### Claim 6 (depends on 1) The method of claim 1, wherein the LTM cell switch comprises a PDCP recovery based on at least one of: the value of the first ID being the same as the value of the second ID; or a value of a third ID of the cell being different from a value of a fourth ID of the candidate cell. ### Claim 7 (depends on 6) The method of claim 6, wherein: the third ID is an LTM no-reset ID for the cell; and the fourth ID is an LTM no-reset ID for the candidate cell. ### Claim 8 (depends on 1) The method of claim 1, wherein the PDCP reestablishment is a PDCP reestablishment of a radio bearer. ### Claim 9 (depends on 8) The method of claim 8, wherein the radio bearer is: an unacknowledged mode (UM) data radio bearer (DRB); an acknowledged mode (AM) DRB; or a signaling radio bearer (SRB). ### Claim 10 (depends on 1) The method of claim 1, wherein the PDCP reestablishment comprises applying a security configuration of the candidate cell. ### Claim 11 An wireless device comprising: one or more processors; and memory storing instructions that, when executed by the one or more processors, cause the wireless device to: perform a layer 1 and/or layer 2 (L1/L2) triggered mobility (LTM) cell switch from a cell of a first base station to a candidate cell of a second base station, wherein the LTM cell switch comprises a packet data convergence protocol (PDCP) reestablishment based on a value of a first identifier (ID) of the cell being different from a value of a second ID of the candidate cell; and transmit, to the second base station via the candidate cell, a radio resource control (RRC) reconfiguration complete message. ### Claim 12 (depends on 11) The wireless device of claim 11, wherein the instructions further cause the wireless device to receive, from the first base station, one or more RRC messages indicating: a configuration of the candidate cell for LTM; the first ID of the cell; and the second ID of the candidate cell. ### Claim 13 (depends on 11) The wireless device of claim 11, wherein the instructions further cause the wireless device to receive a medium access control control element (MAC CE) indicating the LTM cell switch from the cell of the first base station to the candidate cell of the second base station. ### Claim 14 (depends on 11) The wireless device of claim 11, wherein the LTM cell switch further comprises: an RLC reestablishment; and a MAC reset. ### Claim 15 (depends on 11) The wireless device of claim 11, wherein: the first ID is for the PDCP reestablishment of the wireless device; and the second ID is for the PDCP reestablishment of the wireless device. ### Claim 16 (depends on 11) The wireless device of claim 11, wherein the LTM cell switch comprises a PDCP recovery based on at least one of: the value of the first ID being the same as the value of the second ID; or a value of a third ID of the cell being different from a value of a fourth ID of the candidate cell. ### Claim 17 (depends on 16) The wireless device of claim 16, wherein: the third ID is an LTM no-reset ID for the cell; and the fourth ID is an LTM no-reset ID for the candidate cell. ### Claim 18 (depends on 11) The wireless device of claim 11, wherein the PDCP reestablishment is a PDCP reestablishment of a radio bearer. ### Claim 19 (depends on 18) The wireless device of claim 18, wherein the radio bearer is: an unacknowledged mode (UM) data radio bearer (DRB); an acknowledged mode (AM) DRB; or a signaling radio bearer (SRB). ### Claim 20 (depends on 11) The wireless device of claim 11, wherein the PDCP reestablishment comprises applying a security configuration of the candidate cell.