Impact of Primary User Interruptions on Data Traffic in Cognitive Radio Networks: Phantom Jam on Highway

The data traffic in cognitive radio subjected to the interruptions of primary users is studied. By incorporating the essential features of cognitive radio traffic, the traffic is modeled as a group of differential equations, similarly to that of vehicle traffics in highway. The stability of the traffic dynamics is analyzed and the corresponding implications on the cognitive radio design are discussed. Particularly, the small and temporary perturbations of primary user interruption may cause long term traffic jam. The traffic jam is essentially caused by the overreaction of traffic control and chain action of followers. Numerical simulations are used to demonstrate the conclusions of the analysis.