Transmission pattern selection for relay communication with distributed space-time codes

We propose an efficient space-time coded cooperative relay communications scheme that employs linear precoding and transmission-pattern selection. If effectively exploited, distributed spatial diversity and the cooperative nature of multihop communications could significantly increase the coverage area of a wireless network that consists of a number of power-limited relay nodes. We build upon an existing block linear precoding technique for conventional multiple-input multiple-output systems studied in to improve the diversity performance of a multihop relay network. We propose a distributed-relay-selection algorithm to maximize the signal-to-noise ratio at the receiver. We show, via simulation, that the proposed pattern-selection scheme with precoding outperforms the conventional space-time coded relay system using quasi-orthogonal space-time block codes by over 2 dB at a bit error rate of 10^-3.