Modified 802.11-Based Opportunistic Spectrum Access in Cognitive Radio Networks
In this paper, a modified 802.11-based opportunistic spectrum access is proposed for single-channel cognitive radio networks where primary users operate on a slot-by-slot basis. In the authors' opportunistic spectrum access, control frames are used to reduce the slot-boundary impact and achieve channel reservation to improve throughput of secondary users. An absorbing Markov chain model is used to analyze the throughput of secondary users. Simulation results show that the analysis accurately predicts the saturation throughput. Cognitive radio has recently emerged to improve the current spectrum usage. In cognitive radio networks, the Primary Users (PUs) do not always utilize their spectrum.