Method for discovering device in wireless communication system supporting device-to-device communication and apparatus for same

1. A method for discovering a different terminal in a wireless communication system supporting device-to-device (D2D) communication, the method comprising:

transmitting, by a terminal, a discovery signal for detecting neighboring terminals for the D2D communication;

receiving, by the terminal, a response signal as a response with respect to the discovery signal from the different terminal,

wherein the response signal is transmitted by the different terminal when a response delay time determined on the basis of a reception signal-to-interference noise ratio (SINR) terminates;

detecting the different terminal based on the received response signal;

selecting, by the terminal, a specific terminal for performing a terminal discovery process at a next discovery period, from among terminals which have transmitted the response signal; and

transmitting, by the terminal, information of a resource pool for transmission of a discovery message by the selected specific terminal at the next discovery period to the selected specific terminal.

2. The method of claim 1 , wherein the response delay time is determined to be in inverse proportion to the reception SINR.

3. The method of claim 1 , wherein the specific terminal for performing the terminal discovery process at the next discovery period is selected as a terminal which has first transmitted the response signal.

4. The method of claim 1 , wherein the specific terminal for performing the terminal discovery process at the next discovery period is selected as a terminal which has transmitted the response signal the latest.

5. The method of claim 1 , wherein the specific terminal for performing the terminal discovery process at the next discovery period is selected randomly.

6. The method of claim 1 , wherein the discovery signal includes a terminal identifier and/or discovery period information.

7. The method of claim 1 , further comprising: after transmitting the discovery signal, switching the terminal to a reception mode.

8. The method of claim 1 , wherein the terminal transmits the discovery signal only once during a discovery period and maintains a reception mode to receive a response signal transmitted from the neighboring terminals for a remaining time of the discovery period.

9. The method of claim 1 , wherein the specific terminal is a terminal having a shortest response delay time or a longest response delay time.

10. A method for discovering a terminal in a wireless communication system supporting device-to-device (D2D) communication, the method comprising:

receiving, by the terminal, a discovery signal for detecting neighboring terminals for the D2D communication from a neighboring terminal;

determining, by the terminal, a response delay time on the basis of a reception signal-to-interference noise ratio (SINR);

transmitting, by the terminal, a response signal as a response with respect to the discovery signal when the response delay time terminates,

wherein the terminal is detected by the neighboring terminal based on the response signal; and

receiving information of a resource pool for transmitting, by the terminal, a discovery message at a next discovery period from the neighboring terminal, if the terminal is selected by the neighboring terminal to perform a terminal discovery process at the next discovery period.

11. The method of claim 10 , wherein the response delay time is determined to be in inverse proportion to the reception SINR.

12. The method of claim 10 , wherein the reception SINR is derived on the basis of the discovery signal or a reference signal transmitted from the terminal which has transmitted the discovery signal.