Exact outage probability of dual-hop cooperative cognitive networks with relay selection methods, hardware impairment and MRC receiver

In this paper, we evaluate outage probability of dual- hop cooperative cognitive networks under impact of hardware impairment. In particular, we propose two relay selection meth- ods to compensate the performance loss due to the imperfect hardware and the interference constraint at primary network. In the first proposed method, named PRO, the best secondary relay is selected by relying on the channel state information (CSI) of the links between the secondary source and the secondary relays. In the second one, named RE, one of active relays which provides the highest channel gain to the secondary destination is chosen for the cooperation. At the secondary destination, the maximal ratio combining (MRC) technique is used to combine the data received from the source and the selected relay. For performance evaluation and comparison, we drive exact closed- form expressions of outage probability over Rayleigh fading channel, which are verified by Monte Carlo simulations.