Method and device for inter-device communication

A discovery method of a user equipment (UE) for device to device (D2D) communication, the method comprising:

• receiving, from a relay UE, a discovery signal including relay UE discovery information and a relay UE discovery indicator, wherein the relay UE discovery indicator indicates that the relay UE provides a relay service;
• obtaining the relay UE discovery information from the discovery signal;
• transmitting, to the relay UE, a request signal for additional information required for a relayed network connection via the relay UE based on the relay UE discovery information;
• and
• receiving, from the relay UE, the requested additional information in response to the request signal,
• wherein the relay UE discovery information includes a relay UE discovery ID, as sender information, which is a same identifier value for a plurality of relay UEs, and
• wherein the relay UE discovery indicator includes a vehicle-to-vehicle (V2V) service indicator, a vehicle-to-infrastructure (V2I) service indicator, or a vehicle-to-pedestrian (V2P) service indicator.

A relay user equipment (UE) for performing device to device (D2D) communication, the relay UE comprising:

• a transceiver;
• and
• a processor configured to:
• generate a discovery signal including relay UE discovery information and a relay UE discovery indicator, wherein the relay UE discovery indicator indicates that the relay UE provides a relay service;
• identify a transmission resource to transmit the discovery signal;
• control the transceiver to transmit, to a device that is one of devices outside a coverage of a base station, the discovery signal through the identified transmission resource,
• receive, from the device via the transceiver, a request signal for additional information associated with a UE discovery, the additional information used to provide a relayed network connection to the device via the relay UE;
• and
• control the transceiver to transmit, in response to receiving the request signal, the requested additional information to the device,
• wherein the relay UE discovery information includes a relay UE discovery ID, as sender information, which is a same identifier value for a plurality of relay UEs, and
• wherein the relay UE discovery indicator includes a vehicle-to-vehicle (V2V) service indicator, a vehicle-to-infrastructure (V2I) service indicator, or a vehicle-to-pedestrian (V2P) service indicator.

A user equipment (UE) for performing device to device (D2D) communication, the UE comprising:

• a transceiver;
• and
• a processor configured to:
• receive, from a relay UE via the transceiver, a discovery signal including relay UE discovery information and a relay UE discovery indicator, wherein the relay UE discovery indicator indicates that the relay UE provides a relay service;
• obtain the relay UE discovery information from the discovery signal;
• control the transceiver to transmit a request signal, to the relay UE based on the relay UE discovery information, for additional information required for a relayed network connection via the relay UE;
• and
• receive, from the relay UE via the transceiver, the requested additional information in response to the request signal,
• wherein the relay UE discovery information includes a relay UE discovery ID, as sender information, which is a same identifier value for a plurality of relay UEs, and
• wherein the relay UE discovery indicator includes a vehicle-to-vehicle (V2V) service indicator, a vehicle-to-infrastructure (V2I) service indicator or a vehicle-to-pedestrian (V2P) service indicator.