Spectrum sensing is a key technology in Cognitive Radio (CR) and cooperative spectrum sensing is derived due to the effects of channel fading. In this paper, we focus on the optimal number of secondary users in cooperative spectrum sensing to maximize the utility in CR network. By considering both the detection error probability and the resource used by the secondary users in cooperation, we derive the analytical suboptimal number of secondary users in a special CR network where all the SUs have the same SNR. The simulation results show that the utility of suboptimal scheme is greater than that of other schemes and nearly the same as that of the optimal scheme with exhaust search. causes interference to the PU. Also, each SU in the cooperation should pay for the resource used in the process of detection such as sensing power and bandwidth in report to fusion center. We define the utility of the network with consideration of all the above aspects. Then we present the problem of selecting the number of SUs to maximize the utility in a special CR network with all SUs having the same SNR. It is found hard to get an analytical result because the equation is a transcendental equation. So we derive an approximate analytical result by ignoring the cost of the resource in the cooperation. The simulation results show that the utility of the suboptimal analytical results is nearly the same as that of the optimal results with exhaust research. Moreover, the utility of the suboptimal result is greater than other schemes even its detection performance is not optimal.
['Suwen Wu', 'Ming Zhao', 'Jinkang Zhu']
Optimal Number of Secondary Users through Maximizing Utility in Cooperative Spectrum Sensing