METHOD OF SELECTING SYNCHRONIZATION SOURCE IN WIRELESS COMMUNICATION SYSTEM AND APPARATUS THEREFOR

• US 20160174179A1
• Filed: 12/09/2015
• Published: 06/16/2016
• Est. Priority Date: 12/10/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: SEO, Inkwon, SEO, Hanbyul, CHAE, Hyukjin
• Granted Patent: US 10,080,206 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 76/14 Direct-mode setup
• CPC Class Codes: H04W 76/23 Manipulation of direct-mode connections

Abstract

According to one embodiment of the present invention, a method of selecting a synchronization source, which is selected by a D2D (device-to-device) UE in a wireless communication system includes the steps of receiving a plurality of synchronization signals, selecting a plurality of candidate synchronization signals from a plurality of the synchronization signals and determining a synchronization signal in a manner of applying a priority to a plurality of the candidate synchronization signals and selecting a UE, which has transmitted the determined synchronization signal, as a synchronization source. In this case, the application of the priority can be performed in a manner of sequentially applying a plurality of priorities related to a D2D signal according to a priority for the application of the priority.

Claims

1. A method of selecting a synchronization source, which is selected by a D2D (device-to-device) UE in a wireless communication system, comprising the steps of:

receiving a plurality of synchronization signals;

selecting a plurality of candidate synchronization signals from a plurality of the synchronization signals; and

determining a synchronization signal in a manner of applying a priority to a plurality of the candidate synchronization signals and selecting a UE, which has transmitted the determined synchronization signal, as a synchronization source,

wherein the application of the priority is performed in a manner of sequentially applying a plurality of priorities related to a D2D signal according to a priority for the application of the priority.

2. The method of claim 1, wherein a plurality of the priorities related to the D2D signal comprise at least two selected from the group consisting of a priority according to a purpose of data, a priority according to a type of a signal to be transmitted after a synchronization signal, a priority according to a target of a D2D signal to be transmitted after a synchronization signal, a priority according to a position of a synchronization source and a priority according to a type of a synchronization source.

3. The method of claim 2, wherein an importance between elements in each of a plurality of the priorities is indicated to the UE via high layer signaling.

4. The method of claim 1, wherein the priority for the application of the priority is indicated to the UE via high layer signaling.

5. The method of claim 2, wherein the priority according to the purpose of data is defined as important in an order of a public safety message, a UE-specific message and a commercial message.

6. The method of claim 2, wherein the priority according to the type of the signal to be transmitted after the synchronization signal is defined as important in an order of a discovery signal and a communication signal.

7. The method of claim 2, wherein the priority according to the target of the D2D signal to be transmitted after the synchronization signal is defined as important in an order of a discovery signal and a communication signal.

8. The method of claim 2, wherein the priority according to the position of the synchronization source is defined as important in an order of in-coverage and out-coverage.

9. The method of claim 2, wherein the priority according to the type of the synchronization source is defined as important in an order of a relay UE and a UE not the relay UE.

10. The method of claim 1, wherein the priority is identified by one selected from the group consisting of a root index used for generating a synchronization signal, a PD2DSCH (physical D2D synchronization channel), a plurality of SAs (scheduling assignments) and a resource pool from which each of a plurality of the SAs is detected.

11. The method of claim 10, wherein a plurality of the SAs are received based on each of a plurality of the selected candidate synchronization signals.

12. The method of claim 1, wherein the plurality of candidate synchronization signal is selected in order of reception signal strength.

13. The method of claim 1, wherein the plurality of candidate synchronization signal is selected in order of a correlation result.

14. A D2D (device-to-device) UE selecting a synchronization signal in a wireless communication system, comprising:

a transmitter; and

a processor, the processor configured to receive a plurality of synchronization signals, the processor configured to select a plurality of candidate synchronization signals from a plurality of the synchronization signals, the processor configured to determine a synchronization signal in a manner of applying a priority to a plurality of the candidate synchronization signals and select a UE, which has transmitted the determined synchronization signal, as a synchronization source,

wherein the application of the priority is performed in a manner of sequentially applying a plurality of priorities related to a D2D signal according to a priority for the application of the priority.