Strategic behaviour for spectrum access in hybrid overlay/underlay cognitive radio networks

A hybrid overlay/underlay cognitive radio network (CRN) is demonstrated to provide high spectrum efficiency and channel capacity. Decision-making in joining CRNs is one of the major issues of secondary users (SUs). Each SU has the option of joining the spectrum or balking according to the trade-off between the service profit and the delay cost. In this study, the decision-making problem in accessing the hybrid overlay/underlay CRN is addressed using queuing models and game theory. An almost unobservable queuing server is used to model hybrid overlay/underlay CRN. The interaction between the cognitive users is treated as a non-cooperative game. A closed-form expression for the average number of cognitive users as well as associated expected waiting time in both overlay and underlay CRNs is derived. The strategic behaviour for spectrum access of cognitive users in hybrid overlay/underlay CRN is investigated and the existence of symmetric Nash equilibrium is proved as well. Finally, we provide extensive validation results using a wide range of realistic simulation scenarios. The proposed model gives detailed guidance to the decision makers to deploy the suitable strategy according to the available channel situation.