On the Outage Probability of Asynchronous Wireless Cooperative Networks

In wireless cooperative networks, the asynchronism between the relays can be a source of diversity which is similar in its essence to the multipath diversity of frequency selective channels. In this context, an asynchronous two-relay two-hop cooperative wireless network using the Decode-and-Forward protocol is studied. The outage probability in the high Signal to Noise Ratio (SNR) regime is derived and the impact of the relative delay between the two relays on this outage probability is evaluated. We show that for a sufficiently high relative delay, the outage performance becomes independent from the relative delay. Moreover, an outage probability minimization with respect to the power distribution between the transmitting nodes of the network is carried out in the high SNR regime.