Cognitive radio is a communication technology which is designed to serve users to make use of the available bandwidth in a greatest possible amount. Though more research has been done on spectrum sensing and allocation problems, cognitive radio has recently attracted a lot of research interest. This paper shows the concept of cognitive radio networks (CRNs). Cognitive radio is an intelligent fo...

Cognitive Radio technology helps in designing wireless system for efficient deployment of radio spectrum with its sensing technique, self-adaptation and spectrum sharing. Spectrum sharing is an effective method of alleviating the scarcity of radio spectrum problem by allowing unlicensed users(secondary users) to coexist with licensed users (primary users) under the condition of protecting the l...

Cognitive radio is a promising technology aiming to improve the utilization of the radio electromagnetic spectrum. A cognitive radio is a smart device which runs radio applications software to perform signal processing. The use of this software enables the device to sense and understand its environment and actively change its mode of operation based on its observations. Unfortunately, this solu...

With the rapid requirement and development of the green ICT (Information and Communication Technology) technology, the demand for dynamically radio spectrum resources has significantly attentions. The low utilization of licensed spectrum leads to the scarcity of the spectrum resource. The emerging cognitive radio (CR) systems become increasingly important in the wireless green communication. In...

The idea of software defined radio was proposed by J. Mittola. It was a radio designed on programmable chips. The idea of SDR was further enhanced in the form of Cognitive radios. It was proposed by the J.Mittola for the solution of the Spectrum Scarcity problem. Cognitive Radio based networks have the two types of users. One type of the users is known as primary users and the other are known a...

Cognitive radio networks and communications is an emergent paradigm to address the spectrum scarcity challenge in the wireless community. Currently, different wireless systems are regulated by a fixed spectrum assignment strategy. This policy partitions the whole spectrum into a large number of different ranges. Each piece is exclusively used by a specific wireless system. This leads to an unde...