Outage Performance Study of Cognitive Multi-antenna Relay Network with Physical-Layer Network Coding over Nakagami-m Fading Channels

In this paper, we investigate the outage performance of physical-layer network coding (PNC) based cognitive multi-antenna relay network (CMRN) over the Nakagami-m channel. In the spectrum sharing systems, secondary users (SUs) are located on two different primary user (PU) coverage areas. Secondary transceiver nodes exchange their information with the assistance of a multi-antenna relay using PNC protocol. By applying the interference temperature (IT) constraints at the transceiver nodes and relay nodes in secondary systems, we analyze the outage performance in underlay spectrum sharing with the best relay selection criterion. The cumulative distribution function (CDF) of the signal to noise ratio (SNR) for each link are derived to obtain the tight upper bound on the outage probability of the secondary relay system. Simulations results demonstrate the validity and accuracy of the theoretical analysis.