Strategic behavior and admission control of cognitive radio systems with imperfect sensing

This paper conducts the game-theoretic analysis of the behavior of secondary users (SUs) in a cognitive radio (CR) system with a single primary user (PU) band and sensing failures. It is assumed that the sensing errors occur only when an SU is being served by the PU band. It may incorrectly detect there is no PU accessing to the band (called misdetection), or it may wrongly sense that there is an incoming PU but in fact it is not true (called false alarm). When a misdetection occurs, the PU will be blocked and the ongoing SU will drop into a retrial pool called orbit in which it can retry for service after some random time. When a false alarm occurs, the ongoing SU will drop into the retrial orbit. That is, both errors will degrade the quality of service of the system. First, we investigate how the arriving SUs make decisions on whether to join or balk the system which can be studied as a non-cooperative game. We obtain the equilibrium behavior of SUs who want to maximize their benefit in a selfish distributed manner. Second, we derive the socially optimal strategies of SUs from the perspective of the social planner. To use the PU band more efficiently, an appropriate admission fee imposed on each joining SU is proposed based on the gap between the equilibrium strategy and the socially optimal strategy. Finally, theoretic results are validated by numerical analysis and the effect of various parameters on the behavior of SUs is illustrated.