Cooperative Sensing in Cognitive Radios

Cognitive Radios require sensing to detect the presence of Primary Users in a frequency band. Sensing is hampered by shadowing, multi-path and penetration loss through buildings. Hence an individual radio must be designed to be highly sensitive to overcome these signal variations. In this paper we investigate cooperative sensing, where Cognitive Radios use sensing results from other Cognitive Radio. Firstly, we propose using receiver sensitivity to measure gains from cooperative sensing. We show through simulations and probabilistic analysis that number of user polled determine the probability of detection. Next, we present a way to model real world shadowing correlation which is distance dependent and investigate the effect of this correlation to cooperation gain. Lastly, we investigate real world adversarial models and propose a weighting solution that is easy to implement and provides robustness.