A two-relay asymmetric diamond cooperative diversity system over Rayleigh fading channels

A new cooperative communication scheme is presented for asymmetric diamond cooperative relaying networks consisting of two half-duplex relay nodes where both the broadcast and the multiple access part are subject to additive while Gaussian noise. The deterministic cooperative strategy captures the key wireless properties under Rayleigh fading and optimally combines the signals received at sink to enhance diversity gain and throughput. The achievable rates are studied using a number of relaying strategies derived as a generalization of amplify-and-forward, decode-and-forward and detect-and-forward. The key feature of the proposed model is that each relay can adaptively choose between the forwarding schemes in accordance with the received instantaneous signal strength. We demonstrate the efficiency of the proposed model in achieving the capacity upper bound. Empirically, the proposed model is shown to be nearly optimal for a number of fading scenarios.