# US 11,310,757 B2 · Time synchronization method and apparatus

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- Number: US 11,310,757 B2
- Document ID: US11310757B2
- Status: Granted
- Kind: B2
- Application number: 16/874,746
- Filed: 2020-05-15
- Published: 2020-09-03
- Granted: 2022-04-19
- Earliest claimed: 2017-11-16
- Assignees: Huawei Technologies Co., Ltd.
- Applicants: Huawei Technologies Co., Ltd.
- Inventors: Feng Yu; Haifeng Yu; Bo Lin; Guangwei Yu; Feng Gao
- Web page: https://patentgrep.com/patent/US11310757B2

## CPC

- H04W 56/0015: {one node acting as a reference for the others}
- H04W 56/006: {using known positions of transmitter and receiver}
- H04W 56/005: {compensating for timing error by adjustment in the receiver}
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04W 80/02: Data link layer protocols
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

A time synchronization method and an apparatus are disclosed. The method includes: receiving, by a terminal device, a first time sent by an access network device; obtaining a first transmission delay; obtaining a fourth time based on the first transmission delay and the first time; and synchronizing a time of the terminal device based on the fourth time.

## Claims

### Claim 1

A method, comprising:
receiving, by a terminal device, a first frame number and a first value from an access network device, wherein the first value is used to calculate a first time period;
obtaining, by the terminal device, a reference time based on a sum of the first time period and a preset time; and
synchronizing, by the terminal device, a time of the terminal device based on the reference time, wherein a first system frame indicates a time domain location corresponding to the reference time, the first system frame is closest to a second system frame, a frame number of the first system frame is equal to the first frame number, and the terminal device receives the first value in the second system frame.

### Claim 2 (depends on 1)

The method according to the claim 1, wherein the time domain location corresponding to the reference time is a frame header boundary or a frame ending boundary of the first system frame.

### Claim 3 (depends on 1)

The method according to the claim 1, wherein receiving, by the terminal device, the first frame number and the first value from the access network device comprises:
receiving, by the terminal device, a unicast message from the access network device, wherein the unicast message comprises the first value or the first frame number.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the first value comprises values of a plurality of parameters, the plurality of parameters correspond to different time units, and the values of the plurality of parameters are used to calculate the first time period.

### Claim 5

A method, comprising:
determining, by an access network device, a first frame number and a first value, wherein the first value is used to calculate a first time period, the first time period is used to determine a reference time, and the reference time is used to synchronize a time of a terminal device; and
sending, by the access network device, the first frame number and the first value to the terminal device, wherein a first system frame indicates a time domain location corresponding to the reference time, the first system frame is closest to a second system frame, a frame number of the first system frame is equal to the first frame number, and the terminal device receives the first value in the second system frame.

### Claim 6 (depends on 5)

The method according to the claim 5, wherein the time domain location corresponding to the reference time is a frame header boundary or a frame ending boundary of the first system frame.

### Claim 7 (depends on 5)

The method according to the claim 5, wherein sending, by the access network device, the first frame number and the first value to the terminal device comprises:
sending, by the access network device, a unicast message to the terminal device, wherein the unicast message comprises the first value or the first frame number.

### Claim 8 (depends on 5)

The method according to claim 5, wherein the first value comprises values of a plurality of parameters, the plurality of parameters correspond to different time units, and the values of a plurality of parameters are used to calculate a first time period.

### Claim 9

A device, comprising:
a processor; and
a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, wherein the programming instructions instruct the processor to:
receive a first frame number and a first value from an access network device, wherein the first value is used to calculate a first time period;
obtain a reference time based on a sum of the first time period and a preset time; and
synchronize a time of the device based on the reference time, wherein a first system frame indicates a time domain location corresponding to the reference time, the first system frame is closest to a second system frame, a frame number of the first system frame is equal to the first frame number, and the device receives the first value in the second system frame.

### Claim 10 (depends on 9)

The device according to the claim 9, wherein the time domain location corresponding to the reference time is a frame header boundary or a frame ending boundary of the first system frame.

### Claim 11 (depends on 9)

The device according to the claim 9, wherein receiving the first frame number and the first value from the access network device comprises:
receive a unicast message from the access network device, wherein the unicast message comprises the first value or the first frame number.

### Claim 12 (depends on 9)

The device according to claim 9, wherein the first value comprises values of a plurality of parameters, the plurality of parameters corresponds to different time units, and the values of the plurality of parameters are used to calculate a first time period.

### Claim 13

A device, comprising:
a processor; and
a non-transitory computer-readable storage medium coupled to the processor and storing programming instructions for execution by the processor, the programming instructions instruct the processor to:
determine a first frame number and a first value, wherein the first value is used to calculate a first time period, the first time period is used to determine a reference time, and the reference time is used to synchronize a time of a terminal device; and
send the first frame number and the first value to the terminal device, wherein a first system frame indicates a time domain location corresponding to the reference time, the first system frame is closest to a second system frame, a frame number of the first system frame is equal to the first frame number, and the terminal device receives the first value in the second system frame.

### Claim 14 (depends on 13)

The device according to the claim 13, wherein the time domain location corresponding to the reference time is a frame header boundary or a frame ending boundary of the first system frame.

### Claim 15 (depends on 13)

The device according to the claim 13, wherein sending the first frame number and the first value to the terminal device comprises:
sending a unicast message to the terminal device, wherein the unicast message comprises the first value or the first frame number.

### Claim 16 (depends on 13)

The device according to claim 13, wherein the first value comprises values of a plurality of parameters, the plurality of parameters correspond to different time units, and the values of a plurality of parameters are used to calculate a first time period.