Time synchronization method and apparatus
The present disclosure relates to time synchronization methods and apparatus. In one example method, a terminal receives a system information block (SIB) sent by a distributed unit (DU), where the SIB is generated by the DU, the SIB includes time information, and the time information indicates a moment corresponding to a boundary of a system frame number (SFN) at which an end boundary of a system information (SI) window for sending the SIB is located, or indicates a moment corresponding to a boundary of an SFN immediately after an end boundary of an SI window for sending the SIB. The UE processes the time information to obtain a time reference.
1. A time synchronization method, comprising:
sending, by a centralized unit (CU) through an F1 interface, a request message to a distributed unit (DU) in a CU-DU split architecture, wherein the request message is used to request time information and a reference system frame number (SFN) corresponding to the time information, and wherein the time information indicates a moment corresponding to an end boundary of the reference SFN;
receiving, by the CU through the F1 interface, the time information and the reference SFN from the DU; and
sending, by the CU, the time information and the reference SFN to a terminal by using dedicated signaling.
2. The method according to claim 1 , wherein the receiving, by the CU, the time information and the reference SFN from the DU comprises:
periodically receiving, by the CU, the time information and the reference SFN from the DU.
3. The method according to claim 2 , wherein a periodicity at which the CU receives the time information and the reference SFN from the DU is indicated by the CU.
4. The method according to claim 1 , wherein time type information (timeInfoType) of the time information is a local clock.
5. The method according to claim 1 , wherein the time information is a local time or a global positioning system (GPS) time.
6. The method according to claim 1 , wherein the time information comprises uncertain information of time.
7. The method according to claim 1 , wherein a time unit of the time information is nanosecond or millisecond.
8. A time synchronization system, comprising a centralized unit (CU), a distributed unit (DU), and a terminal, wherein:
the CU is configured to send, through an F1 interface, a request message to the DU in a CU-DU split architecture, wherein the request message is used to request time information and a reference system frame number (SFN) corresponding to the time information, and wherein the time information indicates a moment corresponding to an end boundary of the reference SFN;
the DU is configured to:
receive, through the F1 interface, the request message from the CU; and
send, through the F1 interface, the time information and the reference SFN to the CU; and
the CU is further configured to:
receive, through the F1 interface, the time information and the reference SFN from the DU; and
send the time information and the reference SFN to the terminal by using dedicated signaling.
9. The system according to claim 8 , wherein the CU is configured to periodically receive the time information and the reference SFN from the DU.
10. The system according to claim 8 , wherein a periodicity at which the CU receives the time information and the reference SFN from the DU is indicated by the CU.
11. The system according to claim 8 , wherein time type information (timeInfoType) of the time information is a local clock.
12. The system according to claim 8 , wherein the time information is a local time or a global positioning system (GPS) time.
13. The system according to claim 8 , wherein the time information comprises uncertain information of time.
14. The system according to claim 8 , wherein a time unit of the time information is nanosecond or millisecond.