Relay Selection in Distributed Orthogonal Space-Time Block Coded Networks

This paper examines the impact of relay selection on the performance of distributed orthogonal space-time block coding (D-OSTBC) in a wireless network. The relay selection algorithm is based on minimizing the pairwise error probability (PER) or equivalently maximizing the signal to noise ratio (SNR) at the receiver. The receiver can always find the optimal selected relay by exhaustive search where the number of relays rarely exceeds four. It is shown in this work that the proposed scheme achieves full diversity order and provides an additional array gain compared to conventional D-OSTBC. Our results show that the proposed scheme is more power efficient than the conventional D-OSTBC. Since 50% of the time the half of the relay is off, the proposed scheme increases the life time of the relay.