The impact of secondary user mobility and primary user activity on spectrum sensing in cognitive vehicular networks

In cognitive vehicular networks, unlicensed secondary users heavily depend on spectrum sensing to find unused spectrum bands for communications. The performance study of existing spectrum sensing algorithms often overlooks the impact of secondary user mobility.Many of them assume secondary users stationary or with low mobility. In this paper, we investigate the joint impact of secondary user mobility and primary user activity on spectrum sensing for highly dynamic cognitive vehicular networks. We assume that each vehicle is equipped with a cognitive radio for spectrum sensing. The main contribution of this work is to investigate mathematical models for missdetection probability and expected overlapping time duration for spectrum sensing. The proposed method incorporates velocity of secondary user, activity of primary user, initial distance between primary and secondary users and their transmission ranges. In ordered to corroborate the analysis, numerical results obtained from simulations are presented. It is noted that the speed of the vehicular secondary user and the activity of primary user have significant impact on miss-detection probability, but not on false alarm probability. Furthermore, transmission range, velocity and initial separation distance have huge impact on expected overlapping time duration.