The Edition of this text has been written to initiate the newcomer to Spectrum Allocation in Cognitive Radio one of the fastest growing fields in the Wireless Communication world. The major contribution of this book comprises of under the noise uncertainty conditions in the performance of conventional spectrum sensing method under channel allocation scheme. This approach can efficiently decrease the probability of misdetection that declines the interference to cognitive primary user and probability of false alarm which decreases the utilization of spectrum efficiency.Coverage Includes:_ An overview of Cognitive Radio: Spectrum Sensing, Management, Analysis & Decisions_ Cognitive Radio Design Fundamentals, Mechanism of Spectrum Sensing_ Software Defined Radio & Channel Allocation_ Security Threats in Cognitive Radio Networks & Energy Spotting Method.