Power allocation and relay selection in cooperative wireless networks

We propose in this paper, a strategy to minimize the total transmit power in a decode-and-forward (DF) multi-user, multi-relay cooperative uplink, such that each user satisfies its data rate. The base station performs optimal relay selection and also allocates optimal source and relay transmit powers by using the proposed algorithm. The relay selection is based upon the instantaneous user to base station channels, inter-user channels and also the target rates of the users. The simulation results indicate significant power savings over a non-cooperative uplink, under proposed joint relay selection and power minimization algorithm in a DF cooperative uplink when using a space-time coded cooperative diversity.