# US 12,010,579 B2 · Make-before-break (MBB) handover operations > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,010,579 B2 - Document ID: US12010579B2 - Status: Granted - Kind: B2 - Application number: 18/158,442 - Filed: 2023-01-23 - Published: 2023-05-25 - Granted: 2024-06-11 - Earliest claimed: 2019-10-03 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Karthika Paladugu; Ozcan Ozturk; Prasad Reddy Kadiri; Xipeng Zhu - Web page: https://patentgrep.com/patent/US12010579B2 ## CPC - H04W 36/0016: {Hand-off preparation specially adapted for end-to-end data sessions} - H04W 8/24: Transfer of terminal data - H04W 36/0027: {for a plurality of data sessions of end-to-end connections, e.g. multi-call or multi-bearer end-to-end data connections} - H04W 36/0055: {Transmission or use of information for re-establishing the radio link} - H04W 36/185: {using make before break} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Aspects of the present disclosure relate to wireless communications, and more particularly, to performing a handover on a per-data radio bearer (DRB) basis. In some examples, the disclosure is directed to indicating, to a source network entity, a make-before-break (MBB) handover capability of the UE, the MBB handover capability supporting MBB handovers for one or more DRBs identified by the source network entity. In some examples, the disclosure describes receiving, from the source network entity, configuration information for a handover from the source network entity to a target network entity, the configuration information identifying the one or more DRBs supported for the MBB handover. ## Claims ### Claim 1 A method of wireless communication performed by a user equipment (UE), comprising: indicating, to a source network entity, a make-before-break (MBB) handover capability of the UE, the MBB handover capability supporting MBB handovers for one or more data radio bearers (DRBs) identified by the source network entity; receiving, via a radio resource control (RRC) message transmitted by the source network entity, configuration information for a handover from the source network entity to a target network entity, wherein: the configuration information is conveyed in a DRB configuration information element (IE) in the RRC message and identifies the one or more DRBs to be supported for the MBB handover, and the DRB configuration IE comprises: a field indicating whether the MBB handover is supported for a corresponding DRB, and an indication to not reestablish packet data convergence protocol (PDCP) for the corresponding DRB; determining to support the MBB handover if the configuration information identifies at least one MBB DRB; and participating in the MBB handover according to the configuration information by continuing to maintain a connection with the source network entity and continuing to communicate data with the source network entity via the at least one MBB DRB while establishing a connection with the target network entity until a connection with the source network entity is released. ### Claim 2 (depends on 1) The method of claim 1, wherein indicating the MBB handover capability of the UE further comprises providing signaling to the source network entity indicating at least one of: a maximum number of MBB DRBs supported by the UE; or specific DRBs to consider for MBB handover support. ### Claim 3 (depends on 1) The method of claim 1, further comprising indicating a set of DRBs to consider for the MBB handover based on one or more DRB conditions, wherein the one or more DRB conditions comprise at least one of: whether the one or more DRBs provide a communication path having the least amount of interference based on reference signal received power (RSRP); whether the one or more DRBs provide a communication path having the least amount of interference based on reference signal received quality (RSRQ); whether the one or more DRBs provide a communication path having the least amount of interference based on signal to noise interference (SINR) measurements; or whether quality of service (QoS) requirements of the one or more DRBs support ultra-reliable low latency communication (URLLC) services. ### Claim 4 (depends on 1) The method of claim 1, further comprising receiving a handover command from the source network entity, wherein: participating in the MBB handover is based on the handover command; and participating in the MBB handover further comprises: suspending data communication via a non-MBB DRB with the source network after receiving the handover command; and resuming data communication via the non-MBB DRB with the target network entity after a successful handover to the target network entity, wherein the non-MBB DRB is not identified by the configuration information. ### Claim 5 (depends on 1) The method of claim 1, further comprising maintaining a source network entity connection configuration for one or more non-MBB DRBs if the MBB handover is for at least one MBB DRB. ### Claim 6 (depends on 5) The method of claim 5, wherein upon detecting a failure of the MBB handover or a radio link failure (RLF) on the target network entity while a connection with at least one MBB DRB is still active, the method further comprises: declaring an RLF on the target network entity without triggering a radio resource control (RRC) reestablishment; performing a fallback to the source network entity and operating both non-MBB DRBs and MBB DRBs using the source network entity connection configuration; and sending RLF information to the source network entity, the RLF information comprising a cause of failure and any available target cell measurement results. ### Claim 7 (depends on 1) The method of claim 1, further comprising triggering an RRC reestablishment during the MBB handover only when both a source network entity connection fails and a target network entity connection fails. ### Claim 8 A method of wireless communication performed by a source network entity, comprising: receiving, from a user equipment (UE), a make-before-break (MBB) handover capability of the UE, the MBB handover capability supporting MBB handovers for one or more data radio bearers (DRBs) identified by the source network entity; transmitting, via a radio resource control (RRC) message, configuration information for the MBB handover to the UE, wherein: the configuration information is conveyed in a DRB configuration information element (IE) in the RRC message and identified the one or more DRBs supported for the MBB handover, and the DRB configuration IE comprises: a field indicating whether the MBB handover is supported for a corresponding DRB, and an indication to not reestablish packet data convergence protocol (PDCP) for the corresponding DRB; and participating in the MBB handover according to the configuration information by continuing to maintain a connection with the UE and continuing to communicate data with the UE via the one or more DRBs supported for the MBB handover while the UE establishes a connection with a target network entity until a connection with the UE is released. ### Claim 9 (depends on 8) The method of claim 8, further comprising: transmitting the target network entity a set of one or more DRBs to be supported for the MBB handover of a user equipment (UE) from the source network entity to the target network entity; receiving, from the target network entity, an indication of one or more of the set of DRBs the target network entity accepts to support for the MBB handover; and including the indication of one or more of the set of DRBs in the configuration information sent to the UE. ### Claim 10 (depends on 8) The method of claim 8, further comprising: receiving signaling from the UE or another network entity indicating at least one of: a maximum number of MBB DRBs supported by the UE, or specific DRBs to consider for MBB handover support; and determining which DRBs are to be supported for the MBB handover based, at least in part, on the received signaling. ### Claim 11 An apparatus for wireless communication at a user equipment (UE), comprising: one or more processors configured to execute instructions stored on one or more memories and to cause the UE to: indicate a make-before-break (MBB) handover capability of the UE, the MBB handover capability supporting MBB handovers for one or more data radio bearers (DRBs) identified by a source network entity; receive, via a radio resource control (RRC) message transmitted by the source network entity, configuration information for a handover from the source network entity to a target network entity, wherein: the configuration information is conveyed in a DRB configuration information element (IE) in the RRC message and identifies the one or more DRBs to be supported for the MBB handover, and the DRB configuration IE comprises: a field indicating whether the MBB handover is supported for a corresponding DRB, and an indication to not reestablish packet data convergence protocol (PDCP) for the corresponding DRB; determine to support the MBB handover if the configuration information identifies at least one MBB DRB; and participate in the MBB handover according to the configuration information by continuing to maintain a connection with the source network entity and continuing to communicate data with the source network entity via the at least one MBB DRB while establishing a connection with the target network entity until a connection with the source network entity is released. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein, in order to indicate indicate the MBB handover capability, the one or more processors are further configured to cause the UE to provide signaling to the source network entity indicating a maximum number of MBB DRBs supported by the UE. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the one or more processors are further configured to cause the UE to indicate a set of DRBs to consider for the MBB handover based on one or more DRB conditions, wherein the one or more DRB conditions comprise at least one of: whether the one or more DRBs provide a communication path having the least amount of interference based on reference signal received power (RSRP); whether the one or more DRBs provide a communication path having the least amount of interference based on reference signal received quality (RSRQ); whether the one or more DRBs provide a communication path having the least amount of interference based on signal to noise interference (SINR) measurements; or whether quality of service (QOS) requirements of the one or more DRBs support ultra-reliable low latency communication (URLLC) services. ### Claim 14 (depends on 11) The apparatus of claim 11, wherein: the one or more processors are further configured to cause the UE to receive a handover command from the source network entity; the one or more processors are further configured to cause the UE to participate in the MBB handover based on the handover command; and in order to participate in the MBB handover, the one or more processors are further configured to cause the UE to: suspend data communication via a non-MBB DRB with the source network entity after receiving the handover command; and resume data communication via the non-MBB DRB with the target network entity after a successful handover to the target network entity, wherein the non-MBB DRB is not identified by the configuration information. ### Claim 15 (depends on 11) The apparatus of claim 11, wherein the one or more processors are further configured to cause the UE to maintain a source network entity connection configuration for one or more non-MBB DRBs if the MBB handover is for at least one MBB DRB. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein upon detecting a failure of the MBB handover or a radio link failure (RLF) on the target network entity while a connection with at least one MBB DRB is still active, the one or more processors are further configured to cause the UE to: declare RLF on the target network entity without triggering a radio resource control (RRC) reestablishment; perform a fallback to the source network entity and operate both non-MBB DRBs and MBB DRBs using the source network entity connection configuration; and send RLF information to the source network entity, the RLF information comprising a cause of failure and any available target cell measurement results. ### Claim 17 (depends on 11) The apparatus of claim 11, wherein the one or more processors are further configured to cause the UE to trigger an RRC reestablishment during the MBB handover only when both a source network entity connection fails and a target network entity connection fails. ### Claim 18 (depends on 11) The apparatus of claim 11, wherein the one or more processors are further configured to cause the UE to maintain a connection with the source network entity and continue to communicate data with the source network entity via the at least one MBB DRB after receiving a handover command from the source network entity and before connection with the source network entity is released.