Outage behaviour of cooperative underlay cognitive networks with inaccurate channel estimation

In spite of the importance of channel information availability in system design optimization, it is almost impossible to obtain exact channel information with existing channel estimators. Therefore, investigating the effect of inaccurate channel estimation on the performance behaviour of cooperative underlay cognitive networks becomes essential. This paper is devoted to the derivation of an exact closed-form expression for the outage probability of such networks. This expression is subsequently employed in evaluating numerically the corresponding outage performance and it is demonstrated that the analytical results are in excellent agreement with the respective results from computer simulations. It is also shown that the channel estimation error degrades dramatically the performance of unlicensed networks.