Abstract: Localizing primary users using spectrum sensing of secondary users is a key aspect for improved operations in cognitive radio networks．However,malicious secondary users may obfuscate their location reports causing disruption in the network.This paper mainly solve the problem of primary user localization in the presence of secondary users of varying trust．Using localization reports in support of (or against) hypotheses about user locations,we developed the foundations of an evidential reasoning-based approach that uses subjective logic for information fusion and inferencing for localization in the presence of incomplete and conflicting knowledge．To do so,we exploited extensions of subjective logic that accommodate the spatial relationships naturally existing between location reports．After highlighting spatial extensions,we applied them in building an inferencing algorithm for primary user localization．Through simulations,we analyzed its performance and the effect of various design parameters,showing 90% accuracy in localization．Finally,we compared it with other localization techniques via simulations.

Key words: Cognitive radio,Primary user localization,Evidential reasoning,DS theory,saSL