Dynamic Spectrum Access Techniques in Cognitive Radio Networks: A Survey

In today’s scenario the introduction of new wireless applications and services and its increasing demand is creating issues in the allocation of the available radio spectrum which is limited and precious resource. As spectrum utilization depends strongly on time and place, a fixed spectrum assignment leads to under utilization of spectrum. Cognitive radio is a new technology which provides a dynamic spectrum access to improve utilization efficiency of available electromagnetic spectrum. Spectrum sensing helps to detect the spectrum holes (underutilized bands of the spectrum) providing high spectral resolution capability. In this paper, survey of spectrum sensing techniques is presented. The challenges and issues involved in implementation of spectrum sensing techniques are discussed in detail giving comparative study of various methodologies