Relay selection and power allocation for energy saving cooperative wireless networks

A novel single relay selection scheme in cooperative wireless network is provided. Our scheme first chooses a best relay from a set of N available relays and then uses the selected relay to cooperate between the source and destination. The relay selection method was considered both instantaneous channel state information and residual energy information. Specially, cooperation communication will be provoked only when data transmission on the directed link fails so that overheads cooperative relay brings will be cut down. Moreover, power allocation is studied under a more realistic circumstance where the maximum transmission power of each node is constrained. Analysis of outage probability shows that our scheme achieves the same diversity-multiplexing tradeoff as achieved by more complex protocols and simulation results show that the scheme not only improves performance significantly, but also prolongs the network lifetime considerably.