Implementation of the optimal cooperative relay selection based on cross-layer mechanism

Two optimal cooperative relay selection criteria were proposed based on the AF (amplify and forward) and DF (decode and forward) strategies, respectively, by deriving the SER (symbol error rate) of the cooperative transmission system, and a distributed relay selection protocol at MAC layer was further presented to implement the optimal relay selection. Meanwhile, the cooperative diversity schemes at PHY layer was presented along with its performance analysis over Rayleigh fading channels, obtaining the closed-form BER (bit error rate) expressions. Furthermore, computer simulations were conducted to show the BER performances of various cooperative relay selection criteria and cooperative transmission schemes, conforming that the proposed cooperative relay selection criteria outperform the traditional relay selection rules and the proposed transmission schemes could achieve the diversity gain with the BER decreased.