Spectrum sensing is a key technology in the study of cognitive radios, but its attributes are easily influenced by the channel fading. Compared with singleuser spectrum sensing, multiple-user spectrum sensing can overcome the impacts caused by the fading environment of cognitive radio. Since diversity technology has been proved to provide the system high transmission rate and high link reliabil...

Spectrum sensing is a critical functionality of Cognitive Radio(CR) systems. There are number of spectrum sensing techniques. One of techniques is energy detection. Energy detection is the simplest detection method and is the most commonly used. But, energy detection has a hidden terminal problem in real wireless communication, because of SU can be affected by frequency fading and shadowing. Co...

Cognitive radio is a novel technology that can potentially improve the utilization efficiency of the radio spectrum. Spectrum sensing is the key component of cognitive radio technology. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, user cannot distinguish between an unused band and a deep fade. Thus, cooperative spectrum sensing is propose...

The ever growing wireless technologies has put a lot of demand on the usage of available spectrum, thus leading to spectrum underutilization and scarcity. To address this issue and improve spectrum utilization gave rise to the concept of the cognitive radio. The cognitive radio is known to enhance the utilization of spectrum of where a secondary user can utilize the spectrum of the primary user...

Radio frequency spectrum is a quite limited resource. With the increased dependence on modern wireless devices, the management and proper utilization of the spectrum has become a major challenge. The concept of cognitive radio aims to overcome these problems by helping to achieve improved spectral management, utilization, and efficiency. To sense the unoccupied spectrum gap is one of the essent...

This paper reviews applications of fuzzy logic to telecommunications and proposes a novel fuzzy combining scheme for cooperative spectrum sensing in cognitive radio systems. A summary of previous applications of fuzzy logic to telecommunications is given outlining also potential applications of fuzzy logic in future cognitive radio systems. In complex and dynamic operational environments, futur...

Abstract Recent research has identified cognitive radio (CR) as a possible solution for increasing spectrum usage by allowing secondary access to unlicensed bands. Having no interference with the primary system is need this access. Due requirement, sensing becomes crucial component of systems. The ease and effectiveness energy detection make it an appealing technique among popular techniques. u...

Cognitive radio (CR) has become a tempting technology that achieves significant improvement in spectrum utilization. To resolve the hidden terminal problem, collaborative spectrum sensing (CSS), which profits from spatial diversity, has been studied intensively in recent years. As CSS is vulnerable to the attacks launched by malicious secondary users (SUs), certain CSS security schemes based on...

Spectrum sensing is the key component of cognitive radio technology. Spectrum sensing is a tough task because of shadowing, fading, and time-varying nature of wireless channels. However, detection is compromised when a user experiences shadowing or fading effects. In such cases, user cannot distinguish between an unused band and a deep fade. Thus, cooperative spectrum sensing is proposed to opt...