Beacon transmitter placement effect on aggregate interference and capacity-outage performance in a cognitive radio network

This paper presents a study on interference caused by Secondary Users (SUs) due to miss-detection and its effects on the capacity-outage performance of the Primary User (PU) in a cognitive network for two scenarios of beacon transmitter placement: beacon transmitter located at PU transmitter or at PU receiver. Interference analysis shows that aggregate interference power from SUs has a Gamma distribution when beacon transmitter is located at PU receiver, while it can be approximated as a shifted-Gamma distributed random variable for the case of beacon transmitter located at PU transmitter. Based on statistical model for the interference distribution, closed-form expressions of the capacity-outage probability of the PU are developed to examine the effects of various system parameters on the performance of the PU in presence of interference from SUs. Simulation results confirm the validity of the developed analytical models. It is shown that beacon transmitter at PU receiver offers lower interference and hence better capacity-outage probability to the PU than beacon transmitter at PU transmitter.