ABSTRACT

With a rapid growth in the number of users, the demand for a higher throughput in wireless communication systems is also increased, which in turn requires an excessive use of the available spectrum. Scarcity of the available spectrum has become a big issue today as it is signicantly underutilized due to the xed spectrum licensing policies (Federal Communications Commission [FCC], 2005). With this motivation, the concept of cognitive radio (CR) has been proposed as a promising approach for efcient utilization of the available spectrum (Haykin, 2005; Kolodzy, 2005). CR relies on the fact that some frequency bands of the primary (licensed) users (PUs) are unoccupied or partially occupied most of the times. These unoccupied bands are called as white spaces. The main idea behind the

CONTENTS

12.1 Introduction ........................................................................................................................227 12.2 Interference Management in CRNs .................................................................................229