52 Copyright © 2019, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 3 DOI: 10.4018/978-1-5225-5354-0.ch003 ABSTRACT The next generation of emerging wireless technology is dealing with spectrum shortage. For appropriate and practical implementation of latest wireless technologies, the sufcient amount of frequency is needed. Cognitive radio (CR) is introduced as a profcient nominee to manage spectral undersupply problem, as it rapidly increases the use of underutilize spectrum via spectrum sensing. This chapter introduces brief start about spectrum holes in addition to spectrum sensing framework. Further, the chapter explains the issues in spectrum sensing and how the cooperative sensing technique is ft to overcome these issues like shadow fading and receiver uncertainty. Consequently, the various non-cooperative sensing techniques are also discussed including their test statics. The advantages and disadvantages of diferent sensing techniques is exhibited at the end. INTRODUCTION There is always being an immense scope for all the engineers and scientists to create advance, utilize and the technology in best possible way for the betterment of society. In this series, the conventional spectrum allocation regulatory framework have major constrain i.e. under utilization of spectral band, because most of the frequency bands are exclusively provided only to the licensed user and restrict them from any kind of intersystem interference. On the other hand from all over the world nearly 6 billion people have access to mobile phones via using only selected portion of radio frequency due to its fundamental physical limit. These issues motivated the scientists to derive new wireless technology i.e. cognitive radio A Quick Overview of Different Spectrum Sensing Techniques Pooja Joshi Uttarakhand Technical University, India Ashish Bagwari Uttarakhand Technical University, India Ashish Negi Govind Ballabh Pant Engineering College, India