Techniques for Spectrum Sensing in Cognitive Radio Networks: Issues and Challenges

The explosion of wireless applications has created an ever increasing demand for radio spectrum and this has put a lot of pressure on service providers to meet the end user’s requirement for higher bandwidth. In present scenario, the access to radio spectrum for most of the wireless applications/services is based on some well-coordinated but static spectrum allocation principle. However many studies have revealed the low utilization efficiency of radio spectrum by such an allocation principle. The idea of Cognitive Radio stands up for dynamic bandwidth access and efficient bandwidth allocation beyond its previous limits. This paper presents one of the necessary components of a cognitive radio system i.e. Spectrum Sensing. Various techniques that can be used for sensing the unused spectrum by secondary (unlicensed) users are presented and discussed.