Method and device for supporting direct communication service in wireless communication system
A method of a first terminal in a wireless communication system includes establishing a unicast link with a second terminal; determining to change a first old identifier of the first terminal related to the unicast link to a first new identifier of the first terminal; transmitting, to the second terminal, a link identifier (ID) update request message including the first new identifier by using the first old identifier and a second old identifier of the second terminal; in response to the link ID update request message, receiving, from the second terminal, a link ID update accept message including a second new identifier of the second terminal changed from the second old identifier and the first new identifier by using the first old identifier and the second old identifier; and transmitting, to the second terminal, a link ID update acknowledgement message including the second new identifier.
1 . A method performed by a second terminal in a wireless communication system, the method comprising:
establishing a unicast link with a first terminal;
receiving, from the first terminal, a link identifier (ID) update request message including a first new identifier of the first terminal, by using a first old identifier of the first terminal and a second old identifier of the second terminal;
in response to the link ID update request message, transmitting, to the first terminal, a link ID update response message including a second new identifier of the second terminal and the first new identifier, by using the first old identifier and the second old identifier,
wherein, after the second terminal transmits the link ID update response message that includes the first new identifier and the second new identifier to the first terminal, a first data traffic that is based on the first old identifier and the second old identifier is continuously received by the second terminal from the first terminal, until the second terminal receives a second data traffic that is based on the first new identifier and the second new identifier from the first terminal;
determining that a link ID update acknowledgement message including the second new identifier is not received from the first terminal for a predetermined time after the link ID update response message is transmitted; and
based on the determination, retransmitting, to the first terminal, the link ID update response message.
2 . The method of claim 1 ,
wherein a third data traffic that is based on the first old identifier and the second old identifier is continuously transmitted by the second terminal to the first terminal, until the second terminal receives the link ID update acknowledgement message from the first terminal.
3 . The method of claim 1 , further comprising:
transferring, to an access stratum (AS) layer of the second terminal from a higher layer of the second terminal, the first new identifier and the second new identifier;
updating, by the AS layer, the unicast link based on the first new identifier and the second new identifier transferred from the higher layer; and
performing a unicast communication with the first terminal, based on the first new identifier and the second new identifier.
4 . A second terminal in a wireless communication system, the second terminal comprising:
a transceiver; and
a controller configured to:
establish a unicast link with a first terminal,
receive, from the first terminal via the transceiver, a link identifier (ID) update request message including a first new identifier of the first terminal, by using a first old identifier of the first terminal and a second old identifier of the second terminal,
in response to the link ID update request message, transmit, to the first terminal via the transceiver, a link ID update response message including a second new identifier of the second terminal and the first new identifier, by using the first old identifier and the second old identifier,
wherein, after the second terminal transmits the link ID update response message that includes the first new identifier and the second new identifier to the first terminal, a first data traffic that is based on the first old identifier and the second old identifier is continuously received by the second terminal from the first terminal, until the second terminal receives a second data traffic that is based on the first new identifier and the second new identifier from the first terminal,
determine that a link ID update acknowledgement message including the second new identifier is not received from the first terminal for a predetermined time after the link ID update response message is transmitted; and
based on the determination, retransmit, to the first terminal via the transceiver, the link ID update response message.
5 . The second terminal of claim 4 ,
wherein a third data traffic that is based on the first old identifier and the second old identifier is continuously transmitted by the second terminal to the first terminal, until the second terminal receives the link ID update acknowledgement message from the first terminal.
6 . The second terminal of claim 4 , wherein the controller is further configured to:
transfer, to an access stratum (AS) layer of the second terminal from a higher layer of the second terminal, the first new identifier and the second new identifier, and
update, by the AS layer, the unicast link based on the first new identifier and the second new identifier transferred from the higher layer.
7 . The second terminal of claim 6 , wherein the controller is further configured to perform a unicast communication with the first terminal, based on the first new identifier and the second new identifier.