Waiting Probability Analysis for Dynamic Spectrum Access in Cognitive Radio Networks

Cognitive radio networking is emerging paradigm for future generation wireless networks in which cognitive radio users (also known as secondary users) dynamically access the RF spectrum opportunistically without creating harmful interference to primary users. In this paper, the waiting probability of secondary users in the cognitive radio network is analyzed. We consider a cognitive radio network where multiple secondary users (SUs) contend for spectrum access using time division multiple access over idle primary user (PU) channels. Using queue dynamics as Poisson driven stochastic process, we characterize the waiting probability of secondary users. Generally speaking, in practical systems, secondary users of cognitive radio network would have no knowledge of activities of other users, thus the probability of being idle or contention probabilities of SUs' in cognitive radio network have to be assigned according to the available local information. Our focus is on SUs waiting probability analysis, for which a systematic understanding is lacking. Simulation results show that the use of multiple channels and/or multiple slots leads to significant delay reduction and transmission fairness.