Review On Cognitive Radio

Cognitive Radio offers a solution by utilizing the spectrum holes that represent the potential opportunities for noninterfering use of spectrum which requires three main taskscognitive Spectrum Sensing, Spectrum Analysis and Spectrum Allocation modulation techniques. Spectrum involves obtaining the spectrum usage characteristics across multiple dimensions such as time, space, frequency, and code and determining what type of signals are occupying the spectrum one of the challenging issues for cognitive radio system is how to detect the probability of false alarm We review and analysis different spectrum sensing algorithm, based on computational complexity, bandwidth expansion, spectral spillage and performance. We also discuss some methods different methods which provide better result in communication systems. we complement SSCD and feature detection with OFDM signal maximize BER reduction. This algorithm is also developed for threshold detection for some particular users recovery that can be implemented as an independent module in the receiver. The scheme calculating he probability of false alarm under various parameters both computational efficiency for the transmitter and least signal to noise ratio (SNR) loss for the receiver.