Decentralized two-hop opportunistic relaying with limited channel state information

A network consisting of n source-destination pairs and m relays with no direct link between source and destination nodes, is considered. Focusing on the large system limit (large n), the throughput scaling laws of two-hop relaying protocols are studied for Rayleigh fading channels. It is shown that, under the practical constraints of single-user encoding-decoding scheme, and partial channel state information (CSI) at the transmitters (via integer-value feedback from the receivers), the maximal throughput scales as log n even if joint scheduling among relays is allowed. Furthermore, a novel opportunistic relaying scheme with receiver CSI, partial transmitter CSI, and decentralized relay scheduling, is shown to achieve the optimal throughput scaling law of log n.