Method and device for transmitting relay signal for V2X communication in wireless communication system

A first terminal for transmitting a relay signal for vehicle to everything (V2X) communication in a wireless communication system, the first terminal comprising:

• a transmitter and a receiver for transmitting and receiving a radio signal;
• and
• a processor operatively coupled to the transmitter and receiver, wherein the processor is configured such that:
• a first terminal receives allocation information of a first relay resource and second relay resource for a communication group from a base station or a communication group head, wherein the communication group comprises the first terminal, a second terminal, and a third terminal;
• and
• wherein the first terminal receives a data signal from the second terminal through a reception beam for the first relay resource,
• the first terminal transfers the data signal to the third terminal through a transmission beam for the first relay resource;
• and
• the first terminal transmits ACK/NACK for the data signal to the second terminal through a transmission beam for the second relay resource,
• wherein the reception beam for the first relay resource is symmetrical to the transmission beam for the second relay resource,
• wherein the transmission beam for the first relay resource is symmetrical to a reception beam for the second relay resource,
• wherein the first relay resource and the second relay resource are periodically allocated by applying frequency hopping, and
• wherein a cyclic prefix (CP) is applied to each of the first relay resource and the second relay resource, and a last orthogonal frequency division multiplexing (OFDM) symbol is null.