Group communication method and device for providing proximity service

A relay user equipment (UE) for performing a relay operation for a relayed UE communicating with a network node via the relay UE and performing a group communication based on proximity services (ProSe) in a wireless communication system, the relay UE comprising:

• a transceiver;
• and
• a processor,
• wherein the processor:
• transmits, through the transceiver to the network node, a first group communication registration message for the relay UE, including location information of the relay UE, to join the group communication and a second group communication registration message for the relayed UE, received from the relayed UE, to join the group communication,
• receives, through the transceiver from the network node, a downlink signal based on a group communication scheme,
• wherein the group communication scheme is determined to be a multimedia broadcast and multimedia service (MBMS) scheme if a number of UEs other than relayed UE among UEs registered in the network node for the group communication is equal to or greater than a reference value, and the group communication scheme is determined to be a unicast scheme if the number of the UEs other than the relayed UE is smaller than the reference value, and
• wherein the relayed UE is implicitly announced to the network node by transmitting the second group communication registration message not including location information for the relayed UE, and
• transmits, through the transceiver to the relayed UE, the downlink signal received from the network node.

A method for supporting a group communication based on proximity services (ProSe) by a network node in a wireless communication system, the method comprising:

• receiving, from a relay User Equipment (UE) for performing a relay operation for a relayed UE communicating with the network node via the relay UE, a first group communication registration message for the relay UE, including location information of the relay UE, to join the group communication and a second group communication registration message for the relayed UE, transmitted from the relayed UE, to join the group communication;
• determining a group communication scheme to be a multimedia broadcast and multimedia service (MBMS) scheme if a number of UEs other than the relayed UE among UEs registered in the network node for the group communication is equal to or greater than a reference value, and determining the group communication scheme to be a unicast scheme if the number of the UEs other than the relayed UE is smaller than the reference value,
• wherein the relayed UE is implicitly announced to the network node by receiving the second group communication registration message not including location information for the relayed UE;
• and
• transmitting, to the relay UE, a downlink signal based on the group communication scheme.