Relay searching for Distributed Space-Time Coding in decentralized ad hoc networks

Space-Time Coding can effectively increase the communication capacity in multiple antenna systems. In case the terminals cannot be equipped with antenna arrays, Distributed Space-Time Coding (DSTC) can be applied to virtual MIMO channel which is constructed by several single-antenna terminals. A novel way of searching relays for DSTC based on decentralized ad hoc networks is proposed in this paper. The major merit of the new scheme is that the scope of selecting the cooperative relay node is far beyond the SISO transmission range. Thus more opportunities for cooperation are provided, even when the network density is low or the traffic is heavy. As a result, the transmission range is greatly extended without reducing the QoS. Besides, corresponding MAC and routing protocols are presented. Simulation results show that as compared with using SISO, end-to-end throughput of the network increases by 103.9%, while end-to-end latency is reduced by 87.6%.