Method and device for transmitting synchronization signal for D2D (device to device) communication in wireless communication system

• US 10,263,825 B2
• Filed: 09/16/2014
• Issued: 04/16/2019
• Est. Priority Date: 02/05/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Seo, Daewon, Seo, Hanbyul, Kim, Hakseong
• Primary Examiner(s): Islam, Rownak
• Application Number:
  US15/112,928
• Publication Number:
  US 20160337159A1
• Time in Patent Office: 1,673 Days
• Field of Search: 370328, 370329
• CPC Class Codes: H04J 11/0073 Acquisition of primary synchronisation channel, e.g. detection of cell-ID within cell-ID group
• CPC Class Codes: H04J 11/0076 Acquisition of secondary synchronisation channel, e.g. detection of cell-ID group
• CPC Class Codes: H04L 27/261 Details of reference signals
• CPC Class Codes: H04L 27/2662 Symbol synchronisation
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04W 56/001 Synchronization between nodes
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 76/14 Direct-mode setup
• CPC Class Codes: H04W 84/042 Public Land Mobile systems, e.g. cellular systems

Abstract

The present invention relates to a method of detecting a synchronization signal for D2D (device to device) communication of a terminal in a wireless communication system. More particularly, the method includes detecting a first synchronization signal and a second synchronization signal on a specific sub-frame for a synchronization signal period set for D2D communication, wherein the first synchronization signal is generated based on a first of predefined sets of root indexes, the second synchronization signal is generated based on a second of predefined sets of root indexes, and the first set of root indexes and the second set of root indexes are made up of different indexes.

Claims

1. A method of detecting a synchronization signal by a user equipment (UE) for device-to-device (D2D) communication in a wireless communication system, the method comprising;

detecting, by the UE, a first synchronization signal and a second synchronization signal in a specific subframe during a synchronization signal period set for the D2D communication,

wherein the second synchronization signal is located at a start symbol or an end symbol of the specific subframe, and

wherein, when the second synchronization signal is located at the start symbol of the specific subframe, the second synchronization signal is configured to be located at two contiguous symbols; and

performing, by the UE, a channel estimation based on the second synchronization signal located at a symbol next to the start symbol,

wherein the first synchronization signal is generated based on a first root index set among predefined root index sets,

wherein the second synchronization signal is generated based on a second root index set among the predefined root index sets, and

wherein the first root index set and the second root index set are configured by a different index.

2. The method of claim 1, wherein the first synchronization signal is located at a slot boundary between a first slot and a second slot of the specific subframe.

3. The method of claim 1, wherein the second synchronization signal is further located at a slot boundary between a first slot and a second slot of the specific subframe.

4. The method of claim 1, wherein a transition symbol is allocated to a start symbol or an end symbol of the specific subframe.

5. The method of claim 1, wherein the first synchronization signal is used to obtain at least one of first time domain synchronization or first frequency domain synchronization for the D2D communication.

6. The method of claim 5, wherein the second synchronization signal is used to obtain at least one of second time domain synchronization or second frequency domain synchronization based on at least one of the detected first time domain synchronization or the first frequency domain synchronization.

7. The method of claim 1, wherein the first synchronization signal and the second synchronization signal are determined by identification (ID) values different in each symbol according to a predefined pattern.

8. The method of claim 1, wherein the first synchronization signal and the second synchronization signal are allocated using sequences of different lengths.

9. The method of claim 1, wherein an order of detecting the first synchronization signal and the second synchronization signal is determined according to a priority predetermined in the UE.

10. The method of claim 1, wherein a size of the second root index set is greater than a size of the first root index set.

11. A user equipment detecting a synchronization signal for device-to-device (D2D) communication in a wireless communication system, the user equipment comprising:

a transmitter and a receiver; and

a processor, wherein the processor is configured to;

detect a first synchronization signal and a second synchronization signal in a specific subframe during a synchronization signal period set for the D2D communication,

wherein the second synchronization signal is located at a start symbol or an end symbol of the specific subframe, and

wherein, when the second synchronization signal is located at the start symbol of the specific subframe, the second synchronization signal is configured to be located at two contiguous symbols, and

perform a channel estimation based on the second synchronization signal located at a symbol next to the start symbol,

wherein the first synchronization signal is generated based on a first root index set among predefined root index sets,

wherein the second synchronization signal is generated based on a second root index set among the predefined root index sets, and

wherein the first root index set and the second root index set are configured by a different index.