Optimal Parameters for Cooperative Spectrum Sensing in Cognitive Radio Systems

In cognitive radio systems, cooperative spectrum sensing is executed among multiple secondary users to detect spectrum holes without causing deleterious interference to primary users. The larger the number of cooperating secondary users, the greater the performance gain of cooperative sensing. However, the complexity of the cognitive radio system will rapidly increase in the meantime. This paper introduces a novel cooperative spectrum sensing mechanism, which jointly determines the crucial sensing parameters including observation duration, transmission duration and the number of cooperating secondary users. The proposed strategy is able to balance between the channel utilization efficiency and the system complexity as well as to reduce the harmful interference to primary users under a given level. The sensing parameters selection problem is formulated as an optimization problem in such a way as to maximize the target function subject to interference avoidance constraints. A numerical optimization algorithm is proposed to attain the optimal solution. Simulation results illustrate that the mechanism can achieve maximum sensing efficiency in resource-limited cognitive radio systems while meeting interference avoidance limitation.