# US 10,320,600 B2 · Method for D2D signal transmission in wireless communication system, and terminal using same

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- Number: US 10,320,600 B2
- Document ID: US10320600B2
- Status: Granted
- Kind: B2
- Application number: 15/541,101
- Filed: 2016-01-04
- Published: 2018-01-18
- Granted: 2019-06-11
- Earliest claimed: 2015-01-02
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Seungmin Lee; Hanbyul Seo; Yunjung Yi
- Web page: https://patentgrep.com/patent/US10320600B2

## CPC

- H04L 27/2657: {Carrier synchronisation}
- H04L 5/001: {the frequencies being arranged in component carriers}
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 5/0091: {Signalling for the administration of the divided path, e.g. signalling of configuration information}
- H04W 8/00: Network data management
- H04W 8/005: {Discovery of network devices, e.g. terminals}
- H04W 56/00: Synchronisation arrangements
- H04W 56/001: {Synchronization between nodes}
- H04W 56/002: {Mutual synchronization}
- H04W 72/04: Wireless resource allocation
- H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA
- H04W 76/14: Direct-mode setup
- H04W 76/27: Transitions between radio resource control [RRC] states
- H04L 5/0037: {Inter-user or inter-terminal allocation}
- H04L 5/14: Two-way operation using the same type of signal, i.e. duplex
- H04L 27/2655: {Synchronisation arrangements}
- H04W 4/70: Services for machine-to-machine communication [M2M] or machine type communication [MTC]
- H04W 72/20: Control channels or signalling for resource management
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)

## Abstract

Provided is a method for device-to-device (D2D) signal transmission performed by a terminal in a wireless communication system, and a terminal device using the method. The method is characterized by: receiving measurement carrier (MEA_CARRIER) indication information which indicates a single downlink carrier to be used in downlink measurement and synchronization for D2D operation; and using, for the downlink measurement and synchronization for D2D operation, the single downlink carrier indicated by the measurement carrier (MEA_CARRIER) indication information.

## Claims

### Claim 1

A method for transmitting a device-to-device (D2D) discovery signal by a user equipment (UE) in a wireless communication system, the method comprising:
performing synchronization and downlink measurements; and
transmitting the D2D discovery signal based on the synchronization and downlink measurements,
wherein when a second frequency on which the D2D discovery signal is to be transmitted is different from a first frequency on which the UE is connected with a base station, and when the UE is configured with measurement carrier indication information informing a third frequency,
the UE use the third frequency informed by the measurement carrier indication information as reference to perform the synchronization and the downlink measurements for the D2D discovery signal transmission.

### Claim 2 (depends on 1)

The method of claim 1, wherein when there is not an active serving cell for the UE on the second frequency, the third frequency included in the measurement carrier indication information is used to perform the synchronization and the downlink measurements.

### Claim 3 (depends on 2)

The method of claim 2, wherein the third frequency is a frequency linked to the second frequency via system information.

### Claim 4 (depends on 2)

The method of claim 2, wherein the third frequency is a frequency not linked to the second frequency via system information.

### Claim 5

A user equipment (UE) comprising:
a transceiver for transmitting and receiving a radio signal; and
a processor, operatively coupled to the transceiver, wherein the processor is configured to:
perform synchronization and downlink measurements; and
transmit the D2D discovery signal based on the synchronization and downlink measurements,
wherein when a second frequency on which the D2D discovery signal is to be transmitted is different from a first frequency on which the UE is connected with a base station, and when the UE is configured with measurement carrier indication information informing a third frequency, the UE use the third frequency informed by the measurement carrier indication information as reference to perform the synchronization and the downlink measurements for the D2D discovery signal transmission.

### Claim 6 (depends on 5)

The UE of claim 5, wherein when there is not an active serving cell for the UE on the second frequency, the third frequency included in the measurement carrier indication information is used to perform the synchronization and the downlink measurements.

### Claim 7 (depends on 6)

The UE of claim 6, wherein the third frequency is a frequency linked to the second frequency via system information.

### Claim 8 (depends on 6)

The UE of claim 6, wherein the third frequency is a frequency not linked to the second frequency via system information.