# US 2025/0159633 A1 · Time compensation via sidelink relay in telecommunication systems

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- Number: US 2025/0159633 A1
- Document ID: US20250159633A1
- Status: Published application
- Kind: A1
- Application number: 18/837,958
- Filed: 2022-02-16
- Published: 2025-05-15
- Earliest claimed: 2022-02-16
- Assignees: Nokia Technologies Oy
- Applicants: Nokia Technologies Oy
- Inventors: Thomas Haaning JACOBSEN; Renato Barbosa ABREU; Prajwal KESHAVAMURTHY
- Web page: https://patentgrep.com/patent/US20250159633A1

## CPC

- H04W 56/002: {Mutual synchronization}
- H04W 56/0045: {compensating for timing error by altering transmission time}
- H04W 56/001: {Synchronization between nodes}
- H04W 56/004: {compensating for timing error of reception due to propagation delay}
- H04W 56/0055: {determining 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

An apparatus includes a memory and processing circuitry. The processing circuitry is configured to cause the apparatus to request synchronization reference source information from a user equipment, determine whether to conduct an offset compensation based on the synchronization reference source information, and, in response to a determination to conduct the offset compensation, obtain a first propagation delay associated with the apparatus, determine a reference time based on the first propagation delay, and forward the reference time to the user equipment.

## Claims

### Claim at position 1

-24. (canceled)

### Claim 25

An apparatus comprising:
a memory; and
processing circuitry configured to cause the apparatus to:
request synchronization reference source information from a user equipment,
determine whether to conduct an offset compensation based on the synchronization reference source information, and
in response to a determination to conduct the offset compensation,
obtain a first propagation delay associated with the apparatus,
determine a reference time based on the first propagation delay, and
forward the reference time to the user equipment.

### Claim 26

The apparatus according to 25, wherein the processing circuitry is further configured to cause the apparatus to:
obtain a second propagation delay between the user equipment and the apparatus; and
obtain a third propagation delay between the user equipment and a synchronization reference source based on the synchronization reference source information.

### Claim 27

The apparatus according to 25, wherein the synchronization reference source information identifies a type of a synchronization source and a priority of the synchronization source.

### Claim 28

The apparatus according to 26, wherein the processing circuitry is further configured to cause the apparatus to determine not to conduct the offset compensation in response to the synchronization reference source being a global navigation satellite system (GNSS).

### Claim 29

The apparatus according to 26, wherein the processing circuitry is further configured to cause the apparatus to:
obtain the second propagation delay by transmitting a request to the user equipment to transmit a physical sidelink control channel (PSSCH) transmission with a reference signal including a transmission time and a reception time of a next PSSCH reception from the apparatus,
transmitting a first PSSCH transmission to the user equipment,
recording a first time of transmitting the first PSSCH transmission to the user equipment,
receiving a second PSSCH transmission from the user equipment,
recording a first reception time of receiving the second PSSCH transmission from the user equipment,
receiving, from the user equipment, a Rx-Tx value corresponding to a difference between the second transmission time of transmitting the second PSSCH transmission to the apparatus and a second reception time of receiving the first PSSCH transmission from the apparatus, and
determining the second propagation delay based on the Rx-Tx value, the first transmission time, and the first reception time.

### Claim 30

The apparatus according to 26, wherein the processing circuitry is further configured to cause the apparatus to:
set an offset compensation value equal to the first propagation delay; and
determine the reference time based on the offset compensation value.

### Claim 31

The apparatus according to 30, wherein the processing circuitry is further configured to cause the apparatus to:
determine whether the second propagation delay is greater than a first threshold and the third propagation delay is greater than a second threshold; and
set the offset compensation value equal to the offset compensation value plus the difference between the first propagation delay and the second propagation delay in response to the first propagation delay being greater than the second threshold and the third propagation delay being greater than the second threshold.

### Claim 32

The apparatus according to 31, wherein the processing circuitry is further configured to cause the apparatus to:
set the offset compensation value equal to the offset compensation value plus the second propagation delay in response to the second propagation delay being greater than the first threshold and the third propagation delay not being greater than the second threshold.

### Claim 33

The apparatus according to 31, wherein the processing circuitry is further configured to cause the apparatus to:
determine whether the first propagation delay is greater than a third threshold; and
set the offset compensation value equal to the offset compensation value minus the first propagation delay in response to the first propagation delay being greater than the third threshold.

### Claim 34

An apparatus comprising:
a memory; and
processing circuitry configured to cause the apparatus to:
receive, from a first user equipment, a request for time information,
obtain a first propagation delay associated with a second user equipment,
determine a reference time based on the first propagation delay, and
forward the reference time to the first user equipment.

### Claim 35 (depends on 34)

The apparatus according to claim 34, wherein the processing circuitry is further configured to:
obtain a second propagation delay between the first user equipment and the second user equipment; and
obtain a third propagation delay between the first user equipment and a synchronization reference source.

### Claim 36 (depends on 35)

The apparatus according to claim 35, wherein the processing circuitry is further configured to cause the apparatus to:
set an offset compensation value equal to the first propagation delay; and
determine the reference time based on the offset compensation value.

### Claim 37 (depends on 36)

The apparatus according to claim 36, wherein the processing circuitry is further configured to cause the apparatus to:
determine whether a second propagation delay is greater than a first threshold and a third propagation delay is greater than a second threshold; and
set the offset compensation value equal to the offset compensation value plus a difference between the first propagation delay and the second propagation delay in response to the first propagation delay being greater than the first threshold and the second propagation delay being greater than the second threshold.

### Claim 38

A method for synchronizing a reference time in a sidelink relay, the method comprising:
requesting synchronization reference source information from a first user equipment;
determining whether to conduct an offset compensation based on the synchronization reference source information; and
in response to a determination to conduct the offset compensation,
obtaining a first propagation delay of a second user equipment,
determining a reference time based on the first propagation delay, and
forwarding the reference time to the first user equipment.

### Claim 39 (depends on 38)

The method according to claim 38, further comprising:
obtaining a second propagation delay between the first user equipment and the second user equipment; and
obtaining a third propagation delay between the first user equipment and a synchronization reference source based on the synchronization reference source information.

### Claim 40 (depends on 38)

The method according to claim 38, wherein the synchronization reference source information identifies a type of a synchronization source and a priority of the synchronization source, the method further comprising:
determining not to conduct the offset compensation in response to the synchronization source being a global navigation satellite system (GNSS).

### Claim 41 (depends on 39)

The method according to claim 39, wherein the obtaining the second propagation delay comprises:
transmitting a request to the first user equipment to transmit a physical sidelink control channel (PSSCH) transmission with a reference signal including a transmission time and a reception time of a next PSSCH reception from the second user equipment;
transmitting a first PSSCH transmission to the first user equipment;
recording a first time of transmitting the first PSSCH transmission to the first user equipment;
receiving a second PSSCH transmission from the first user equipment;
recording a first reception time of receiving the second PSSCH transmission from the first user equipment;
receiving, from the first user equipment, a Rx-TX value corresponding to a difference between the second transmission time of transmitting the second PSSCH transmission to the second user equipment and a second reception time of receiving the first PSSCH transmission from the second user equipment; and
determining the second propagation delay based on the Rx-Tx value, the first transmission time, and the first reception time.

### Claim 42 (depends on 38)

The method according to claim 38, wherein the determining the reference time comprises:
setting an offset compensation value equal to the first propagation delay; and
determining the reference time based on the offset compensation value.

### Claim 43 (depends on 42)

The method according to claim 42, wherein the determining the reference time further comprises:
determining whether the second propagation delay is greater than a first threshold and a third propagation delay is greater than a second threshold;
setting the offset compensation value equal to the offset compensation value plus a difference between the second propagation delay and the third propagation delay in response to the second propagation delay being greater than the first threshold and the third propagation delay being greater than the second threshold; and
setting the offset compensation value equal to the offset compensation value plus the second propagation delay in response to the second propagation delay being greater than the first threshold and the third propagation delay not being greater than the second threshold.

### Claim 44 (depends on 42)

The method according to claim 42, wherein the determining the reference time further comprises:
determining whether the first propagation delay is greater than a third threshold; and
setting the offset compensation value equal to the offset compensation value minus the first propagation delay in response to the first propagation delay being greater than the third threshold.