Performance analysis of randomised space-time block codes for amplify-and-forward cooperative relaying

In recent studies (Verde et al.), capitalising on randomised space-time block coding (STBC), a decentralised coding method has been developed for amplify-and-forward (A&F) relays, which can closely achieve the performance of a centralised A&F linear dispersion coding (LDC) scheme and notebly outperform the decentralised A&F LDC counterpart, by requiring a reduced amount of signalling and processing overhead. However, A&F relaying process introduces correlation among the noise samples at the destination which, along with the non-Gaussian nature of the relaying channel and the fact that the relays are located in different positions, significantly complicates the performance analysis of the system. In this study, a theoretical performance analysis of the randomised STBC A&F rule is carried out in terms of average pairwise error probability to evaluate its attainable diversity order. Numerical results are provided to corroborate the analytical findings.