Updatable relay selection for distributed EO-STBC cooperative system with ARQ protocol

In this paper, we investigate the closed loop extended orthogonal - space time block codes in decode-and-forward (DF) cooperative networks and propose an updatable Automatic Repeat reQuest (ARQ) protocol including relay selection. The relays correctly decoding the signals are incorporated into the relay set, and if there exist more than 4 relays in this set, we only choose 4 optimal relays based on the channel information. According to the number of the relays in the set, we bring forward a distributed EO-STBC method in the relay transmission to enhance the system performance. Simulation results prove that the proposed scheme can achieve better performance than the best relay and distributed-Alamouti scheme.