Probabilistic Analysis of Mutual Interference in Cognitive Radio Communications

Mutual interference plays decisive role in successful operation of a cognitive radio (CR) network. In order to evaluate the interference experienced by a primary user, we have considered a realistic communication scenario where the transmission of any secondary user is not only constrained by the primary network but also constrained from the secondary network itself so that harmful interference to other secondary users can be avoided. The transmission probability for each secondary user has been derived using joint density function of the distance from secondary user to the primary receiver and the distance between adjacent secondary users. Based on this analysis, a closed-form expression for expected mutual interference experienced by a primary receiver is derived. In addition, a cognitive network is simulated to evaluate the aggregated interference experienced by the primary receiver along with constraints from both primary and secondary networks. The proposed interference modeling is validated by comparing theoretical and simulated results of aggregated interference experienced by the primary receiver.