Opportunistic MAC Protocols for Cognitive Radio Based Wireless Networks

Recently, cognitive radio technology has attracted more and more attention since it is a novel and effective approach to improve the utilization of the precious radio spectrum. We propose MAC protocols for the cognitive radio based wireless networks. Specifically, the cognitive MAC protocols allow secondary users to identify and use the available frequency spectrum in a way that constrains the level of interference to the primary users. In our schemes, each secondary user is equipped with two transceivers. One of the transceivers is tuned to a dedicated control channel, while the other is used as a cognitive radio that can periodically sense and dynamically use an identified available channels. Our proposed schemes integrate the spectrum sensing at the PHY layer and packet scheduling at the MAC layer. Our schemes smoothly coordinate the two transceivers of the secondary users to enable them to collaboratively sense and dynamically utilize the available frequency spectrum.