# US 11,910,342 B2 · System and methods for controlling out-of-network D2D communications

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- Number: US 11,910,342 B2
- Document ID: US11910342B2
- Status: Granted
- Kind: B2
- Application number: 17/410,846
- Filed: 2021-08-24
- Published: 2021-12-09
- Granted: 2024-02-20
- Earliest claimed: 2013-05-10
- Assignees: Futurewei Technologies, Inc.
- Applicants: Futurewei Technologies, Inc.
- Inventors: Philippe Sartori; Vipul Desai; Mazin Al-Shalash; Anthony C. K. Soong; George Calcev; Brian Classon
- Web page: https://patentgrep.com/patent/US11910342B2

## CPC

- H04W 56/0015: {one node acting as a reference for the others}
- H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC]
- H04W 8/005: {Discovery of network devices, e.g. terminals}
- H04W 56/002: {Mutual synchronization}
- H04W 76/14: Direct-mode setup
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Embodiments are provided herein for determining a synchronizing master for device-to-device (D2D) communication in a cellular network environment. In an embodiment, a user equipment (UE) receives a discovery signal comprising a timing reference, and determines a transmitter of the discovery signal. In accordance with the determination of the transmitter of the discovery signal, the UE performs one of synchronizing to the timing reference in the discovery signal and transmitting a second discovery signal. The UE performs the synchronizing to the timing reference if the transmitter of the discovery is a cellular network. Alternatively, the UE transmits the second discovery signal upon determining that the transmitter of the discovery signal is a second UE that is out of coverage of a cellular network.

## Claims

### Claim 1

A method by a user equipment (UE), the method comprising:
receiving a discovery signal identifying a second UE;
determining a signal quality of the discovery signal;
configuring the UE as a master device or a slave device for device-to-device (D2D) communications with the second UE in accordance with the discovery signal; and
transmitting a second discovery signal, the second discovery signal indicating a timing reference between the UE and the second UE in accordance with the signal quality.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
participating, by the UE, in a D2D communication session with the second UE as either a timing information receiver or a timing information transmitter, based on the configuring the UE as the master device or the slave device.

### Claim 3 (depends on 1)

The method of claim 1, wherein the UE participates in a D2D communication session with the second UE over an available uplink carrier as either a timing information receiver or a timing information transmitter.

### Claim 4 (depends on 1)

The method of claim 1, wherein the discovery signal indicates whether the second UE is synchronized with a cellular network or is otherwise outside a coverage area of the cellular network.

### Claim 5 (depends on 1)

The method of claim 1, wherein the UE is in coverage of a cellular network.

### Claim 6 (depends on 1)

The method of claim 1, wherein the discovery signal indicates a relative separation of the second UE from a base station of a cellular network.

### Claim 7 (depends on 1)

The method of claim 1, wherein the second discovery signal indicates a relative separation of the second UE from a base station of a cellular network, and wherein the signal quality is determined according to the relative separation of the second UE from the base station.

### Claim 8 (depends on 1)

The method of claim 1, wherein the determining the signal quality of the discovery signal comprises:
detecting a power level of the discovery signal.

### Claim 9 (depends on 1)

The method of claim 1, wherein the discovery signal indicates that a transmitter of the discovery signal is a timing information receiver entity or a timing information transmitter entity.

### Claim 10 (depends on 1)

The method of claim 1, wherein the discovery signal comprises one or more messages, each one of the messages indicating that a transmitter of the discovery signal is a timing information receiver entity or a timing information transmitter entity.

### Claim 11 (depends on 1)

The method of claim 1, wherein the second discovery signal is transmitted by the UE upon determining that a transmitter of the discovery signal is the second UE out of coverage of a cellular network.

### Claim 12 (depends on 1)

The method of claim 1, further comprising:
upon receiving the discovery signal from the second UE, receiving authorization from a cellular network, the authorization enabling the UE to act as a timing information transmitter for the second UE; and
upon receiving the authorization from the cellular network, switching to a timing information transmitter mode.

### Claim 13 (depends on 1)

The method of claim 1 further comprising:
upon receiving a signal without a second timing reference from the second UE, transmitting a third discovery signal.

### Claim 14 (depends on 1)

The method of claim 1, wherein the master device provides at least one of timing information or resource allocation information to the slave device.

### Claim 15

A user equipment (UE) comprising:
at least one processor; and
a non-transitory computer readable storage medium storing programming for execution by the at least one processor, the programming including instructions to cause the UE to perform operations including:
receiving a discovery signal identifying a second UE;
determining a signal quality of the discovery signal;
configuring the UE as a master device or a slave device for device-to-device (D2D) communications with the second UE in accordance with the discovery signal; and
transmitting a second discovery signal, the second discovery signal indicating a timing reference between the UE and the second UE in accordance with the signal quality.

### Claim 16 (depends on 15)

The UE of claim 15, the operations further comprising:
participating in a D2D communication session with the second UE as either a timing information receiver or a timing information transmitter, based on the configuring the UE as the master device or the slave device.

### Claim 17 (depends on 15)

The UE of claim 15, wherein the UE participates in a D2D communication session with the second UE over an available uplink carrier as either a timing information receiver or a timing information transmitter.

### Claim 18 (depends on 15)

The UE of claim 15, wherein the discovery signal indicates whether the second UE is synchronized with a cellular network or is otherwise outside a coverage area of the cellular network.

### Claim 19 (depends on 15)

The UE of claim 15, wherein the UE is in coverage of a cellular network.

### Claim 20 (depends on 15)

The UE of claim 15, wherein the discovery signal indicates a relative separation of the second UE from a base station of a cellular network.

### Claim 21 (depends on 15)

The UE of claim 15, wherein the second discovery signal indicates a relative separation of the second UE from a base station of a cellular network, and wherein the signal quality is determined according to the relative separation of the second UE from the base station.

### Claim 22 (depends on 15)

The UE of claim 15, wherein the determining the signal quality of the discovery signal comprises:
detecting a power level of the discovery signal.

### Claim 23 (depends on 15)

The UE of claim 15, wherein the discovery signal indicates that a transmitter of the discovery signal is a timing information receiver entity or a timing information transmitter entity.

### Claim 24 (depends on 15)

The UE of claim 15, wherein the discovery signal comprises one or more messages, each one of the messages indicating that a transmitter of the discovery signal is a timing information receiver entity or a timing information transmitter entity.

### Claim 25 (depends on 15)

The UE of claim 15, wherein the second discovery signal is transmitted by the UE upon determining that a transmitter of the discovery signal is the second UE out of coverage of a cellular network.

### Claim 26 (depends on 15)

The UE of claim 15, the operations further comprising:
receiving authorization from a cellular network, upon receiving the discovery signal from the second UE, the authorization enabling the UE to act as a timing information transmitter for the second UE; and
switching to a timing information transmitter mode, upon receiving the authorization from the cellular network.

### Claim 27 (depends on 15)

The UE of claim 15, the operations further comprising:
transmitting a third discovery signal, upon receiving a signal without a second timing reference from the second UE.