Cooperative decode-and-forward relaying with orthogonal space-time block code over doubly correlated Nakagami-m fading channels

In this study, the authors investigate the performance of cooperative decode-and-forward multiple-input multiple-output relaying system with orthogonal space-time block code transmissions over doubly correlated Nakagami-m fading channels, where the source, relay and destination nodes are all equipped with multiple antennas. They also include correlated and independent Rayleigh fading channels as special cases. Only when the relay node could receive the signal from the source correctly, it will forward source information to the destination. For two types of receivers at the destination, maximal ratio combining and selection combining, the authors provide the compact closed-form expressions for cumulative distribution function (CDF) and probability density function of the instantaneous end-to-end signal-to-noise ratio (SNR). Besides, the exact analytical expressions are also derived for the outage probability (OP) and symbol error rate (SER) relying on CDF. Furthermore, they present the asymptotic expressions for OP and SER in the high SNR regime, from which they gain an insight into the system performance and derive the achievable diversity order and array gain. The analytical expressions are validated by Monte-Carlo simulations.