Link-failure probabilities for practical cooperative relay networks

In this paper, practical cooperative diversity schemes are proposed and investigated. The outage probability is used to evaluate four constant-power decode-and-forward cooperative schemes: pre-select one relay, best-select relay, simple relay, and ST-coded relay. Two new methods for improving these approaches, called simple distributed power allocation and m-group ST-coded relay, are proposed. It is shown that the performance of simple relay and ST-coded relay is improved significantly by employing the proposed power allocation without an increase in implementation complexity. Similarly, m-group ST-coded relay gains in lower complexity with only a slight degradation in performance. Performance of the various schemes in a network is evaluated through the link-failure probability.