# US 11,910,341 B2 · Method and apparatus for synchronization reference source selection > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,910,341 B2 - Document ID: US11910341B2 - Status: Granted - Kind: B2 - Application number: 17/276,134 - Filed: 2018-10-11 - Published: 2022-02-17 - Granted: 2024-02-20 - Earliest claimed: 2018-10-11 - Assignees: Lenovo (Beijing) Limited - Applicants: Lenovo (Beijing) Limited - Inventors: Jie Hu; Jing Han; Haiming Wang; Lianhai Wu; Xiaodong Yu; Zhennian Sun - Web page: https://patentgrep.com/patent/US11910341B2 ## CPC - H04W 56/0015: {one node acting as a reference for the others} - H04W 56/002: {Mutual synchronization} - H04W 56/004: {compensating for timing error of reception due to propagation delay} - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Synchronization reference source selection may be used to support advanced services of NR V2X. One method may be performed by a user equipment (UE) in a wireless network. The method includes: broadcasting group information for identifying a wireless communication group including the UE; and broadcasting a special synchronization signal identification for identifying the UE as a synchronization reference source in the wireless communication group. ## Claims ### Claim 1 A method performed by a user equipment (UE) in a wireless network, the method comprising: receiving, from a base station, information indicating a special synchronization signal identifier that is used to indicate a particular UE as a synchronization reference source in a wireless communication group having a highest priority; broadcasting group information comprising a group identifier (ID) for identifying the wireless communication group including the UE, wherein the wireless communication group comprises a plurality of UEs, and each UE of the plurality of UEs has a corresponding unique identifier; and broadcasting the special synchronization signal identifier indicating that the UE is the synchronization reference source in the wireless communication group having the highest priority. ### Claim 2 (depends on 1) The method of claim 1, wherein the method is performed if the UE detects that members in the wireless communication group do not use the same synchronization reference source. ### Claim 3 (depends on 1) The method of claim 1, wherein the wireless network comprises a plurality of base stations supporting a plurality of communication standards, and the method further comprises receiving timing offset information between two or more base stations of the plurality of base stations, and the timing offset information is included in a system information block (SIB) message or a radio resource control (RRC) message. ### Claim 4 A method performed by a user equipment (UE) in a wireless network, which is a member of a wireless communication group, the method comprising: receiving, from a base station, information indicating a special synchronization signal identifier that is used to indicate a particular UE as a synchronization reference source in the wireless communication group having a highest priority; selecting the synchronization reference source by using the special synchronization signal identifier and group information, wherein the wireless communication group comprises a plurality of UEs, and each UE of the plurality of UEs has a corresponding unique identifier, wherein the special synchronization signal identifier indicates a leader of the wireless communication group and the group information identifies the wireless communication group. ### Claim 5 (depends on 4) The method of claim 4, further comprising: setting the special synchronization signal identifier as a highest priority identifier to be selected as the synchronization reference source. ### Claim 6 (depends on 4) The method of claim 4, wherein selecting the synchronization reference source comprises, if a synchronization type of the UE is set to be group prioritized and the special synchronization signal identifier is detected, selecting the leader as the synchronization reference source by using the special synchronization signal identifier and the group information. ### Claim 7 (depends on 4) The method of claim 4, wherein selecting the synchronization reference source further comprises: if a synchronization type of the UE is not set to be group prioritized, detecting presence of a candidate synchronization signal in broadcast information received by the UE. ### Claim 8 (depends on 7) The method of claim 7, wherein selecting the synchronization reference source further comprises: during detecting the presence of the candidate synchronization signal, if the special synchronization signal identifier is detected, selecting the leader as the synchronization reference source by using the special synchronization signal identifier and the group information. ### Claim 9 (depends on 4) The method of claim 4, wherein the wireless network comprises a plurality of base stations supporting a plurality of communication standards, and the method further comprises receiving timing offset information between two or more base stations of the plurality of base stations, and the timing offset information is included in a system information block (SIB) message or a radio resource control (RRC) message. ### Claim 10 A user equipment (UE) in a wireless network, comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive, from a base station, information indicating a special synchronization signal identifier that is used to indicate a particular UE as a synchronization reference source in a wireless communication group having a highest priority; determine group information comprising a group identifier (ID) for identifying the wireless communication group including the UE, wherein the wireless communication group comprises a plurality of UEs, each UE of the plurality of UEs has a corresponding unique identifier; and broadcast the special synchronization signal identifier and the group information. ### Claim 11 (depends on 10) The UE of claim 10, wherein the at least one processor is configured to cause the UE to broadcast the special synchronization signal identifier and the group information repeatedly. ### Claim 12 (depends on 10) The UE of claim 10, wherein the at least one processor is configured to cause the UE to broadcast the special synchronization signal identifier and the group information if the UE detects that members in the wireless communication group do not use a same synchronization reference source. ### Claim 13 (depends on 10) The UE of claim 10, wherein the wireless network comprises a plurality of base stations supporting a plurality of communication standards, and the UE further comprises a receiver that receives timing offset information between two or more base stations of the plurality of base stations, and the timing offset information is included in a system information block (SIB) message or a radio resource control (RRC) message. ### Claim 14 A user equipment (UE) in a wireless network, which is a member of a wireless communication group, the UE comprising: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive, from a base station, information indicating a special synchronization signal identifier that is used to indicate a particular UE as a synchronization reference source in a wireless communication group having a highest priority; detect presence of the special synchronization signal identifier and presence of group information comprising a group identifier (ID), wherein the wireless communication group comprises a plurality of UEs, each UE of the plurality of UEs has a corresponding unique identifier; and select a synchronization reference source by using the special synchronization signal identifier and the group information, wherein the special synchronization signal identifier indicates a leader of the wireless communication group and the group information identifies the wireless communication group. ### Claim 15 (depends on 14) The UE of claim 14, wherein, if a synchronization type of the UE is set to be group prioritized and the special synchronization signal identifier is detected, the at least one processor is configured to cause the UE to select the leader as the synchronization reference source by using the special synchronization signal identifier and the group information. ### Claim 16 (depends on 14) The UE of claim 14, wherein, if a synchronization type of the UE is not set to be group prioritized, the at least one processor is configured to cause the UE to detect presence of a candidate synchronization signal in broadcast information. ### Claim 17 (depends on 16) The UE of claim 16, wherein, if the special synchronization signal identifier is detected during detecting the presence of the candidate synchronization signal, the at least one processor is configured to cause the UE to select the leader as the synchronization reference source by using the special synchronization signal identifier and the group information. ### Claim 18 (depends on 14) The UE of claim 14, wherein the wireless network comprises a plurality of base stations supporting a plurality of communication standards, and the receiver further receives timing offset information between two or more base stations of the plurality of base stations, and the timing offset information is included in a system information block (SIB) message or a radio resource control (RRC) message.