Power allocation for Incremental-Selective Decode-and-Forward cooperative communications over Rician fading channels

In this paper we consider a relaying communication system over Rician fading channels. In this system we assume simple Incremental-Selective Decode-and-Forward (ISDF) protocol, which is jointly combining incremental and selective DF relaying protocols. In this protocol, storage or retransmission of the first phase signal are not allowed. We analyze the symbol error rate (SER) performance of the recommended protocol with M-PSK modulation. We evaluate the performance of the protocol in the frequency nonselective slow Rician fading channels. Using the approximation of the SER expression, the optimal power allocation is investigated. Our results show that at least 50% of total power must be used by direct link and the reminder can be used by the relay. In addition, the results indicate that the power allocation coefficient just depend on the quality of source-relay channel and the quality of relay-destination.