Performance analysis of cooperative transmission for cognitive wireless relay networks

In this paper, we consider cooperative transmission in cognitive wireless relay networks (CWRNs) over frequency-selective fading channels. We propose a new distributed space-time-frequency block code (DSTFBC) for a two-hop nonregenerative CWRN, where a primary source node and multiple secondary source nodes convey information data to their desired primary destination node and multiple secondary destination nodes via multiple cognitive relay nodes with dynamic spectrum access. The proposed DSTFBC is designed to achieve spatial diversity gain as well as allow for low-complexity decoupling detection at the receiver. Pairwise error probability is then analysed to study the achievable diversity gain of the proposed DSTFBC for different channel models including Rician fading and mixed Rayleigh-Rician fading.