Relay Cyclic Delay Diversity: Modeling & System Performance

A cooperative communication scheme referred to as relay cyclic delay diversity (RCDD) is presented in this paper. The scheme is based on a set of distributed relay nodes (RNs) with each node associated with a certain cyclic shift in order to generate artificially multi-path diversity and equivalently frequency diversity. RCDD is an open loop scheme and the user terminal (UT) only needs to estimate an effective channel from all the RNs and not the channel from each RN. The effective channel induced by RCDD is frequency selective and can be exploited by a maximum signal to interference noise ratio (SINR) scheduler which improves substantially the system throughput. The SINR of the RCDD is derived analytically and the performance of the method is evaluated in a dynamic multi-cell multi-user simulator. The results show considerable SINR gains that translate into substantial cell throughput gains compared to 1-hop systems.