Performance of hybrid decode-amplify-forward protocol for multiple relay networks over independent and non-identical flat fading channels

In this study, the authors investigate the hybrid decode-amplify-forward (HDAF) relaying protocol for the multiple parallel relays over independent and non-identical distribution flat Rayleigh fading channels using maximum ratio combining at the destination. They derive closed-form tight bounds for the outage probability and bit error rate (BER) of the HDAF relaying protocol. They also show that the outage probability performance of this protocol outperforms decode-forward (DF) protocol, and is very close to amplify-forward (AF) scheme. On the other hand, the BER of the HDAF scheme is superior to AF protocol, and is close to BER of DF scheme. From practical point of view, when taking into account outage and BER performance of a system together, the HDAF protocol performs better than AF and DF schemes by combining the merits of both. Also, the authors investigate power allocation among the relay nodes to minimise the system outage probability and BER under total and individual power constraints. Numerical results are provided to show the correctness of our analytical expressions.