Partial gradient based cooperative sensing in distributed cognitive radio ad-hoc networks

In ad hoc networks, the unused spectrum resources can be effectively sensed by cognitive radio technology, and transmission performance will be improved. Cooperative spectrum sensing is necessary because a single node cannot detect the existence of primary user accurately due to shadowing, noise and fading in wireless channels. Gradient based cooperative sensing (GBCS) is a widely used scheme in distributed cooperative spectrum sensing. However, as the nodes of cognitive radio ad-hoc networks increasing, the efficiency of GBCS degrades because the complexity rises. To solve the problem, a partial-GBCS (F-GBCS) scheme is proposed in this paper. The ROC performance and energy consumption are balanced by SNR-based adaptive threshold and optimal cooperative numbers. Simulation results show that under the proposed scheme, the value of object function, which evaluates the comprehensive performance of the algorithm, is improved by 37%, and the robustness of cooperative spectrum sensing is guaranteed in large-scale cognitive ad hoc networks. Meanwhile, the interference to primary users is suppressed and equipment power consumption is reduced.