Medium Access Control (MAC) protocols plays very important role in Cognitive Radio (CR) networks. CR enables the Secondary (unlicensed) Users (SU) to opportunistically access the spectrum unused by the Primary (licensed) Users (PU). The two main functions of the CR MAC are interference control and avoidance for PUs and collision avoidance among SUs. This book is the case of overlay spectrum sharing mode of contention based, distributed, non cooperative spectrum sharing access mode protocol. In order to devise efficient CR MAC protocol, it will be efficient to use CSMA/CA based protocol as it...