Cooperative spectrum sensing in realistic RF environment

Fixed spectrum licensing policies are unsuitable to meet RF spectrum demand by emerging technologies. Spectrum scarcity is hindering the enhancement of current services or deployment of new services operating in RF spectrum. On the contrary, many portions of the licensed spectrum remain unused or underused for significant period of time creating possibility of opportunistic spectrum access without license. Spectrum sensing is practiced in most of the existing opportunistic spectrum access methods. However, these methods consider identical fading or shadowing channels and ignore spatial variation of unlicensed users, hence fail to capture realistic scenario. We introduce an improved cooperative spectrum sensing technique which incorporates non-identical fading and shadowing, and weighs each non-licensee user´s contribution appropriately considering the received power and positional displacements of the users. The proposed method demonstrates better detection accuracy and higher spectrum utilization with fewer cooperating users than other existing methods.