The impact of overlap regions in cognitive radio networks

In this paper, we evaluate the impact of cognitive radio transmissions on primary radio communications. Our objective is to characterize precisely, based on the position of secondary users, the vulnerability areas where interference to primary radios can be generated. To do so, we detail all the cases where overlap regions between primary and secondary transmitters exist and derive the vulnerability area for each case. Through OMNeT++ simulations, we illustrate that there is a dependency between the size of the overlap area and the impact on the primary receivers: the smaller the overlap region, the smaller the impact on the receivers in this area. Furthermore, an efficient channel selection by cognitive radios can reduce by 40% the interference observed on primary receivers.