Outage Analysis of DF-relayed Cognitive Underlay Networks Over EGK Fading Channels

In this paper we analyze the outage performance of a dual hop cognitive underlay network employing a decode and forward relay. The analysis has been modeled over extended generalized K fading channel taking the interference temperature as a constraint so that the transmit power of the secondary source and relay do not exceed this limit. This results in constraints on the transmit powers of the secondary network also and hence ensures no interference with the primary communication which is imperative in cognitive underlay systems. The analytical expression for the outage probability is derived employing the probability density functions and the cumulative distribution functions of the channel gains for the various links in the system. The expression for the outage probability is calculated in terms of Fox's H functions. Our results demonstrate the dependence of outage probability performance on various parameters of the system under the power constraints already defined. The analytical results are verified with the help of MATLAB simulations.