Cognitive radio is a software radio whose control processes leverage situational knowledge and intelligent processing to work towards achieving some goal related to the needs of the user, application, and/or network. Cognitive radio is born of the need to introduce intelligence and flexibility in managing spectrum resources that become increasingly valuable with the rapid proliferation of stand...

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...

The increasing demand of wireless applications has put a lot of limitations on the use of available radio spectrum is limited and precious resource. Many survey of spectrum utilization shows that entire spectrum is not used at all the times, so many of the radio spectrum is underutilized. Some of the frequency bands in the spectrum are unoccupied, some of the frequency bands less occupied and f...

| Cognitive radio is an exciting emerging technology that has the potential of dealing with the stringent requirement and scarcity of the radio spectrum. Such revolutionary and transforming technology represents a paradigm shift in the design of wireless systems, as it will allow the agile and efficient utilization of the radio spectrum by offering distributed terminals or radio cells the abili...

In this paper, we integrate overlay cognitive radio technology into 4G cellular networks for the sharing of TV spectrum. On one hand, OFDM is a promising technique for high-speed data transmission over multipath fading channels and has been considered to be the best candidate for 4G mobile networks. On another hand, the overlay cognitive radio model makes it possible to have two concurrent tran...

Spectrum sensing is a challenging task for cognitive radio. In this paper we analyze collaborative spectrum sensing over Nakagami fading channel in cognitive radio. Through computer simulation, we evaluate the performance of collaborative spectrum sensing and signal detection by employing OR, AND and MAJORITY rules as decision combining. Energy detection is one of the popular spectrums sensing ...

Cognitive radio systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. In this paper, we first provide the performance analysis of such systems over fading channels. We derive the average symbol error probability of dispersed spectrum cognitive radio systems for two cases, where the channel for each frequency diversity band experie...

In this letter, a mutated ant colony optimization (MACO) cognitive radio engine is proposed, and it is the first time to apply ACO algorithm to this problem. The cognitive radio is a promising technology nowadays to alleviate the apparent scarcity of available radio spectrum, and the cognitive radio engine determines the optimal radio transmission parameters for the system. The cognitive engine...

Cognitive Radio allows Software Defined Radio terminal to perceive its environment and then interact with it. In other words, cognitive radio can collect information from its surroundings, model them and try to adapt its behavior according to them. The main aim of this paper is to shed light on the concept of spectrum sensing and adaptive cognitive radio and propose an application implemented o...

Interference and delay are considered as the major reasons limiting the capacity and increasing the new call blocking probability in cellular system. In this paper we introduce a novel strategy based on cognitive radio. Cognitive radio is defined as a radio or system that senses its environment and can dynamically and autonomously change its transmitter parameters based on interaction with the ...