Publication

Abstract : Cognitive Radio Networks (CRN) use spectrum sensing techniques to provide connectivity to secondary users (SU) while ensuring nil or minimal interference is caused to the licensed user. Noisy conditions severely impact the finding of the spectrum white spaces as SUs generally operate at low signal power conditions and spectrum sensing may get affected by shadowing or fading. Estimating the channel state information estimation under cooperative method will provide a solution to tackle this issue wherein the primary channel state is estimated, for taking a decision on whether the primary channel is occupied or not. Multistage threshold techniques provide better accuracy in finding out the vacant primary channels, but it increases the complexity of the system. Review of the research works shows that the existing techniques are developed for a single RF signal scenario and hence not useful in a multiple network environment. Hence, in this scenario, there is a need to develop an efficient and accurate technique to detect spectrum white spaces to work effectively for multiple networks. In order to implement the spectrum sensing effectively in heterogeneous wireless networks, a novel energy detection scheme is proposed in this work for accurate spectrum sensing and efficient dynamic spectrum access to the secondary users. Probability of detection of vacant primary channel is improved in this method by combination of transmitter detection and channel state information. The combination of sensing decision and channel state estimation has been used for better spectrum sensing. Under this technique, secondary user information is processed with the help of a specially designed channel filter using universal bandpass sampling algorithm. Some important features of the spectrum sensing technique proposed in this research work are that it can sense the spectrum in heterogeneous network scenarios and under low Signal-to-Noise Ratio (SNR) conditions. The results obtained with this technique are compared with the other traditional methods which showed that it gives better performance and the same has been verified for various SNR values.