Date Added: Jan 2013
In this Modernistic World folks want everything compact and mobile. As the wireless devices dominate the market, the necessity of wireless network and wireless communication has been increased. The Regulations of FCC (Federal Communications Commission) allocates 2.4GHz to ISM band. It is used by major part of the population because technologies like Zigbee, Bluetooth, Wi-Fi/802.11 and etc use this unlicensed band. As a result the authors are running out of spectrum. Shortage in the unlicensed band must be alleviated. The promising solution is Cognitive Radio (CR). In this paper, CR and its features are reviewed in detail. Basics of Software Defined Radio (SDR) and related technologies were discussed. This paper gives the overview about SDR and describes the functions and importance of cognitive Radio.