Diversity Analysis of Distributed Space-Time Codes in Relay Networks with Multiple Transmit/Receive Antennas

The idea of space-time coding devised for multiple-antenna systems is applied to the problem of communication over a wireless relay network, a strategy called distributed space-time coding, to achieve the cooperative diversity provided by antennas of the relay nodes. In this paper, we extend the idea of distributed space-time coding to wireless relay networks with multiple-antenna nodes and fading channels. We show that for a wireless relay network with antennas at the transmit node, antennas at the receive node, and a total of antennas at all the relay nodes, provided that the coherence interval is long enough, the high SNR pairwise error probability (PEP) behaves as if and if , where is the total power consumed by the network. Therefore, for the case of , distributed space-time coding achieves the maximal diversity. For the case of , the penalty is a factor of which, compared to , becomes negligible when is very high.