Decentralized Relay Coordination for Weighted Sum Rate Maximization in TDD Multiuser Multi-Relay Systems

We propose decentralized relay coordination algorithms and corresponding channel state information (CSI) signaling concepts for weighted sum rate maximization, via linear downlink transceiver optimization in multiuser multi-relay MIMO network. Two decentralized algorithms are developed with the local CSI requirements at the base station and the relay nodes. In the first proposed algorithm, the generalized channel inversion precoding is utilized at the base station to avoid the second hop channel sharing requirements among the relay nodes. Further, decentralized transceiver optimization of the relay nodes and users are developed to maximize the weighted sum rate. For the second proposed approach, we provide a novel structure of the precoding matrix of the base station. Then decentralized joint BS, relay and user transceiver design is developed to further improve the performance. Moreover, CSI signaling and decentralized processing in TDD system are analyzed. Simulation results show the effectiveness of the decentralized relay coordination compared to the existing algorithms.