Multi-User Precoding and Energy-Efficient Relaying Scheme in Multi-Relay Systems

The multi-user multi-relay system is investigated in this paper. Multi-user precoding is utilized at the source node to mitigate the interference among data streams. Since the transmitting power of relay nodes is constrained independently, the interference among data streams can not be completely mitigated at the destination nodes. An energy-efficient relaying scheme is proposed at relay nodes to mitigate the inter-stream interference and save the transmitting power of relay nodes. The average saved transmitting power is derived from simple system parameters. Simulation results demonstrate that the energy-efficient relaying scheme outperforms the conventional simple relaying scheme on the system capacity, reliability performance and the transmitting power of relay nodes.