Transmit Preprocessing for Cluster Based Multi-User Relay Systems

In a mobile relay system, the idle users can be formed as a cluster to support nearby active users. In order to reduce the complexity of the processing in the relay nodes and destination nodes, a novel transmit preprocessing method is proposed for the cluster based multi-user relay system. Block diagonalization (BD) algorithm is adopted twice in the proposed method to remove inter-cluster and intra-cluster interference simultaneously, and the relay nodes are just in simple amplify-and-forward (AF) mode. Compared to the conventional signal processing methods, the proposed method can achieve better tradeoff between sum capacity performance and processing complexity in the relay nodes.