# US 12,120,563 B2 · Method and apparatus for secondary base station change in mobile 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 12,120,563 B2 - Document ID: US12120563B2 - Status: Granted - Kind: B2 - Application number: 17/592,519 - Filed: 2022-02-04 - Published: 2023-02-16 - Granted: 2024-10-15 - Earliest claimed: 2021-08-05 - Assignees: Blackpin Inc. - Applicants: Blackpin Inc. - Inventors: Soenghun Kim - Web page: https://patentgrep.com/patent/US12120563B2 ## CPC - H04W 36/00835: {Determination of neighbour cell lists} - H04W 36/0058: {Transmission of hand-off measurement information, e.g. measurement reports} - H04W 36/0069: {in case of dual connectivity, e.g. decoupled uplink/downlink} - H04W 36/00698: {using different RATs} - H04W 36/362: {Conditional handover} - H04W 36/008355: {Determination of target cell based on user equipment [UE] properties, e.g. UE service capabilities} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A method and apparatus for secondary base station change in a mobile communication system with multiple are provided. Method for secondary node change includes transmitting to a target SN a control message requesting conditional secondary node change, receiving from the target SN a Xn message including conditional secondary node change information, transmitting to a terminal LTE DL message for conditional secondary node change, receiving from the terminal a 1st LTE UL message including a transaction identifier, receiving from the terminal a conditional reconfiguration identifier and transmitting to a source SN a control message for data forwarding. ## Claims ### Claim 1 A method performed by a Master Node (MN), the method comprising; transmitting, by the MN, to a target Secondary Node (SN) a first base station control message requesting resource allocation; receiving, by the MN, from the target SN a second base station control message accepting request, determining, by the MN, to perform a 1st reconfiguration procedure or a 2nd reconfiguration procedure; performing, by the MN, the 1st reconfiguration procedure in response to MN receiving a 2nd information; performing, by the MN, the 2nd reconfiguration procedure in response to MN not receiving the 2nd information; transmitting, by the MN in response to MN determining to perform the 1st reconfiguration procedure, to a terminal a first Downlink (DL) message, wherein the first DL message includes a first identifier and one or more CondReconfigToAddMod, wherein each of the one or more CondReconfigToAddMod includes an execution condition, a second identifier, and a reconfiguration message, wherein the first identifier is a transaction identifier and the second identifier is a conditional reconfiguration identifier; receiving, by the MN, from the terminal a first Uplink (UL) message, wherein the first UL message includes the first identifier; and transmitting, by the MN, to a source SN a third base station control message after a second UL message is received from the terminal, wherein the second UL message includes the second identifier, wherein the second identifier corresponds to the reconfiguration message in the CondReconfigToAddMod, wherein the second UL message is received after the first UL message is received, and wherein the third base station control message requests release of the source SN, wherein 1st information is comprised in the first base station control message in case that the 1st reconfiguration procedure is requested, wherein the 2nd information comprises a specific cell's global identity. ### Claim 2 (depends on 1) The method of claim 1, wherein the first base station control message further includes measurement results for the second base station. ### Claim 3 (depends on 1) The method of claim 1, wherein the first base station control message includes first information indicating that a first reconfiguration procedure is requested. ### Claim 4 (depends on 3) The method of claim 3, wherein the first reconfiguration is conditional PSCell addition. ### Claim 5 (depends on 3) The method of claim 3, wherein the first information includes assistance information for the second base station to determine resource for the terminal. ### Claim 6 (depends on 1) The method of claim 1, wherein the first base station control message further includes Data Radio Bearer (DRB) configuration of a one or more DRBs. ### Claim 7 (depends on 1) The method of claim 1, further comprising: receiving from the target SN a second base station control message in response to the first base station control message. ### Claim 8 (depends on 7) The method of claim 7, wherein the second base station control message includes second information in response that first information was included in the first base station control message. ### Claim 9 (depends on 8) The method of claim 8, wherein the second information includes a cell global identifier of a specific cell for a first reconfiguration procedure. ### Claim 10 (depends on 8) The method of claim 8, wherein the second information includes information related to a plurality of PSCells. ### Claim 11 (depends on 7) The method of claim 7, wherein the second base station control message includes Cell Group configuration. ### Claim 12 (depends on 11) The method of claim 11, wherein the Cell Group configuration includes the reconfiguration message. ### Claim 13 (depends on 11) The method of claim 11, wherein the Cell Group configuration further includes: information related to Secondary Cell Group bearer; and Discontinuous Reception configuration of Secondary Cell Group. ### Claim 14 (depends on 1) The method of claim 1, wherein the first DL message includes a parameter for execution condition. ### Claim 15 (depends on 1) The method of claim 1, wherein the first DL message further includes a parameter indicate the execution condition is related to measurement configuration of Secondary Cell Group. ### Claim 16 (depends on 15) The method of claim 15, wherein the parameter for execution condition is determined by the source SN. ### Claim 17 (depends on 1) The method of claim 1, further comprising: transmitting to the target SN a third base station control message, wherein the third base station control message includes the second UL message. ### Claim 18 (depends on 1) The method of claim 1, wherein: the first UL message is not forwarded to the first SN; and the second UL message is forwarded to the first SN. ### Claim 19 (depends on 1) The method of claim 1, further comprising: transmitting to the target SN a fourth base station control message, wherein the fourth base station control message includes Packet Data Convergence Protocol (PDCP) sequence number, and wherein data forwarding is performed based on the PDCP sequence number. ### Claim 20 A Master Node (MN) in a wireless communication system, the MN comprising: a transceiver configured to transmit and receive a signal; and a controller configured to control the transceiver to: transmit to a target Secondary Node (SN) a first base station control message requesting resource allocation; receive from the target SN a second base station control message accepting request, determine to perform a 1st reconfiguration procedure or a 2nd reconfiguration procedure; perform the 1st reconfiguration procedure in response to MN receiving a 2nd information; perform the 2nd reconfiguration procedure in response to MN not receiving the 2nd information; transmit, in response to MN determining to perform the 1st reconfiguration procedure, to a terminal a first Downlink (DL) message, wherein the first DL message includes a first identifier and one or more CondReconfigToAddMod, wherein each of the one or more CondReconfigToAddMod includes an execution condition, a second identifier, and a reconfiguration message, wherein the first identifier is a transaction identifier and the second identifier is a conditional reconfiguration identifier; receive from the terminal a first Uplink (UL) message, wherein the first UL message includes the first identifier; and transmit to a source SN a third base station control message after a second UL message is received from the terminal, wherein the second UL message includes the second identifier, wherein the second identifier corresponds to the reconfiguration message in the CondReconfigToAddMod, wherein the second UL message is received after the first UL message is received, and wherein the third base station control message requests release of the source SN, wherein 1st information is comprised in the first base station control message in case that the 1 st reconfiguration procedure is requested, wherein the 2nd information comprises a specific cell's global identity.