Improved Relay Selection Strategy for Hybrid Decode-Amplify Forward Protocol

—To improve the problems of noise amplification and error propagation of the fixed cooperation schemes in cooperative communications, a relay selection strategy is proposed based on the hybrid decode-amplify-forward protocol. It can adaptively determine cooperation schemes according to the Channel Status Information (CSI) of the source-relay. Then it selects the best relay from the candidate relay set of the two fixed cooperation schemes, for a maximum Signal-Noise Ratio (SNR) in the destination. The theoretical analyses and the simulation results all show that the proposed strategy can improve the performance of the Bit-Error-Rate (BER) and the outage probability significantly, when compared with the relay selection strategies of the fixed cooperation schemes. Also it performs excellent with the increased number of the relays.