Method for relaying discovery signal for terminal-to-terminal direct communication in wireless communication system, and apparatus therefor

A user equipment (UE) for performing device-to-device (D2D) communication in a wireless communication system, the UE comprising:

• a transceiver configured to transmit and receive a signal to and from another UE or a network;
• and
• a processor configured to process the signal,
• wherein the processor is further configured to:
• detect a plurality of discovery signals transmitted from a same source UE,
• determine first discovery signals for relaying within a discovery period among the plurality of discovery signals based on a first hop count contained in each of the plurality of discovery signals, and
• control the transceiver to relay at least one of the first discovery signals to another UE,
• wherein the processor increases or decreases a second hop count contained in each of the at least one of the first discovery signals based on the first hop count,
• wherein, when a number of the first discovery signals is greater than a predetermined value, at least one second discovery signal is selected for relaying to the another UE among the first discovery signals based on a probability that each of the first discovery signals is selected as the at least one second discovery signal,
• wherein a number of the at least one second discovery signal is equal to the predetermined value, and
• wherein the probability that each of the first discovery signals is selected as the at least one second discovery signal increases based on a third hop count contained in each of the first discovery signals.