A trust-based method for cooperative spectrum sensing in cognitive radio networks

Cognitive radio has been treated as a promising candidate for reusing underutilized or unused spectrum resources of licensed users without interference to licensed users by means of opportunistic spectrum access. Reliable spectrum sensing is one of foundational techniques for cognitive users to detect spectrum holes and monitor licensed users´ activities in cognitive radio. However, many factors make it much difficult for single cognitive user to accurately and rapidly identify the activity status of licensed users, such as very low signal-to-noise ratio, and noise uncertainty, and fading, and shadowing, and quite short sensing time, etc. In this paper, we proposed a weighted scheme for cooperative spectrum sensing considering trust factor of each collaborative user to improve the global sensing performance in cognitive radio networks. The cognitive users performed spectrum sensing using energy detectors and transmitted their binary local decisions as well as binary information on the success or failure in previous data transmission to the fusion center for a global decision based weighted decision fusion on the absence or presence of the licensed users´ activities. Weighted values depended on trust factors of corresponding cognitive users. Simulation results showed that the proposed method can efficiently overcome the influence of the aforementioned negative factors.