A distributed relay selection method for relay assisted Device-to-Device communication system

Relay assisted transmission could efficiently enhance the performance of Device-to-Device (D2D) communication when D2D user equipments (UEs) are too far away from each other or the quality of D2D channel is not good enough for direct communication. The relay selection problem for D2D communication underlaying cellular network is studied in this paper. We proposed a distributed relay selection method for relay assisted D2D communication system. The method firstly coordinates the interference caused by the coexistence of D2D system and cellular network and eliminates improper relays correspondingly. Next, the best relay is chosen among the optional relays using a simple distributed method. Numerical results show that performance of the proposed method is close to the optimal (centralized) method.