A cyclic time-delay-based distributed precoding relay system

In order to alleviate the multipath interference of the MIMO multi-relay system and improve the system spectrum efficiency, this paper presents a cyclic delay distributed precoding relay scheme. The channel state information (CSI) sent from the source node, according to its phase information and relay node´s matrix match, sends the signals to destination node via specific relay node, rather than the tradition broadcasts to all repeaters. Then at the relay node, we design a distributed precoding cyclic delay relay scheme to improve and balance the destination node´s received signal power. At last, the receiver achieves the signals coherent combination and completes the system design. Simulation results show the proposed distributed precoding scheme improves the system capacity, reduces the encoding complexity, and is well suited for multi-relay system.