Method and device for reducing power of device in wireless communication system supporting direct device to device communication

1. A method by a device in a wireless communication system supporting a direct device to device (D2D) communication, the method comprising:

transmitting, to an opponent device, a first D2D parameter associated with a discontinuous reception (DRX) for a D2D communication with the opponent device;

receiving, from the opponent device, a second D2D parameter associated with the DRX for the D2D communication with the opponent device;

entering a sleep mode during the D2D communication with the opponent device, based on the second D2D parameter;

transmitting a paging signal for the opponent device to a base station connected to the device to request a transmission of the paging signal to the opponent device, based on data to be transmitted to the opponent device being generated during the sleep mode;

receiving, from the opponent device, a paging acknowledgment signal in response to the paging signal; and

resuming the D2D communication based on the paging acknowledgment signal, with the opponent device which received the paging signal through the base station.

2. The method of claim 1 , further comprising:

performing the sleep mode based on the second D2D parameter.

3. The method of claim 1 , wherein the device enters the sleep mode when an inactivity timer expires.

4. The method of claim 1 , wherein the entering of the sleep mode comprises:

transmitting a sleep mode request message to the opponent device; and

entering the sleep mode when a response message corresponding to the sleep mode request message is received from the opponent device.

5. The method of claim 1 , further comprising releasing the D2D communication after the entering the sleep mode, if there is no data to transmit until a preset timer expires.

6. A device in a wireless communication system supporting a direct device to device (D2D) communication, the device comprising:

a transceiver configured to transmit and receive a signal; and

at least one processor configured to:

transmit, to an opponent device, a first D2D parameter associated with a discontinuous reception (DRX) for a D2D communication with the opponent device,

receive, from the opponent device, a second D2D parameter associated with the DRX for the D2D communication with the opponent device,

enter a sleep mode during the D2D communication with the opponent device, based on the second D2D parameter,

transmit a paging signal for the opponent device to a base station connected to the device to request a transmission of the paging signal to the opponent device, based on data to be transmitted to the opponent device being generated during the sleep mode,

receive, from the opponent device, a paging acknowledgment signal in response to the paging signal, and

resume the D2D communication based on the paging acknowledgment signal, with the opponent device which received the paging signal through the base station.

7. The device of claim 6 , wherein the at least one processor is further configured to perform the sleep mode based on the second D2D parameter.

8. The device of claim 6 , wherein the at least one processor is further configured to enter the sleep mode when an inactivity timer expires.

9. The device of claim 6 , wherein the at least one processor is further configured to:

transmit a sleep mode request message to the opponent device, and

enter the sleep mode when a response message corresponding to the sleep mode request message is received from the opponent device.

10. The device of claim 6 , wherein the at least one processor is further configured to release the D2D communication after entering the sleep mode, if there is no data to transmit until a preset timer expires.

11. A method by a base station in a wireless communication system supporting a direct device to device (D2D) communication, the method comprising:

receiving, from a first device performing a D2D communication with a second device, a paging signal for the second device which is an opponent device of the first device; and

transmitting the received paging signal to the second device,

wherein a D2D parameter associated with a discontinuous reception (DRX) for the D2D communication is negotiated between the first device and the second device before the first device enters a sleep mode,

wherein the paging signal is received from the first device after the first device enters the sleep mode during the D2D communication,

wherein a paging acknowledgment signal is transmitted from the second device to the first device in response to the paging signal, and

wherein the D2D communication is resumed between the first device and the second device based on the paging acknowledgment signal.

12. A base station in a wireless communication system supporting a direct device to device (D2D) communication, the base station comprising:

a transceiver configured to transmit and receive a signal; and

at least one processor configured to:

receive, from a first device performing a D2D communication with a second device, a paging signal for the second device, which is an opponent device of the first device, and

transmit the received paging signal to the second device,

wherein a D2D parameter associated with a discontinuous reception (DRX) for the D2D communication is negotiated between the first device and the second device before the first device enters a sleep mode,

wherein the paging signal is received from the first device after the first device enters the sleep mode during the D2D communication,

wherein a paging acknowledgment signal is transmitted from the second device to the first device in response to the paging signal, and

wherein the D2D communication is resumed between the first device and the second device based on the paging acknowledgment signal.