Towards a Realistic Primary Users´ Behavior in Single Transceiver Cognitive Networks

Most of the models intended to describe the throughput of Primary (PUs) and Secondary (SUs) users of Cognitive Radio Networks (CRNs) assume that PUs only change their activity state (ON/OFF) in the beginning of each SU´s operation cycle, admitting that PUs are synchronized with SU´s operation cycle. This letter characterizes a more realistic scenario where PUs can randomly change their activity state during the SU´s operation cycle. We derive an analytical model for the PU´s throughput and its validation is assessed through simulation results. The analysis shows that assuming synchronized PUs leads to an undervaluation of the interference caused to PUs, and the interference decreases as more SU´s operation cycles are performed per ON/OFF PU´s activity state.