Spectrum Sensing using Fuzzy Logic in Cognitive Radio

Abstract

Wireless communication was a technology that brought a revolution in the field of communication and with the arrival came the gush of customers in wireless network. Cognitive radio is an intelligent device , in literal meaning cognitive means intelligence, which means it has a knowledge about the surroundings and it works according to the surrounding. The need of latest technology like cognitive radio was raised because of the scarcity of the bandwidth that was being sensed in the tech field . Unused portions of bandwidth going waste or unused by the users , can be re-used was the main motive . cognitive radio helps to remove the problem of scarcity in a spectrum. This is done by allowing the secondary users to enter the spectrum.(The unoccupied and unused part of the spectrum). Sensing the spectrum availability is the main challenge once the motive is decided Spectrum sensing refers to sensing whether the spectrum is available for secondary user without disturbing the primary user .There are various spectrum sensing techniques that are being applied to sense the availability . Energy detection method involves comparing the power of the received signal to the threshold calculated. other methods like cyclostationary filter and matched filter are used in order to find the same. Each method for sensing the spectrum has its drawback and advantages. Fuzzy logic is applied for a better result detecting free spectrum . fuzzy is applied in two stage spectrum sensing techniques [3]. In between the region of two threshold lies the fuzzy region that is the confused region and fuzzy logic is applied to find better and improved results.