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Improved weighted cooperative spectrum sensing algorithm based on reliability in cognitive radio networks

Cognitive radio (CR) is a prominent candidate to solve the spectrum scarcity problem faced by the proposed as well as existing wireless services. It exploits the opportunities, also called as spectrum holes, and created due to the underutilization of the licensed spectrum. Spectrum sensing plays the most important role to detect these spectrum holes. Individual CR sometimes faces problems in accurate spectrum sensing due to shadowing, hidden terminal problem and multipath fading. Cooperative spectrum sensing (CSS) is considered as a one of the solutions to tackle these problems in which more than one CR users collaboratively perform the spectrum sensing. In this paper all the CR nodes participating in CSS have been distinguished based on their reliability. The reliability of nodes depends on the past decisions of corresponding node and of the central node (fusion center). Considering the reliability of each CR a new reliability based weighted algorithm has been proposed for CSS. The proposed algorithm improves the spectrum sensing performance mainly in low SNR regions of the primary users which is a most challenging task in cognitive radio.