Optimum number of secondary users in cooperative spectrum sensing using adaptive threshold

Cognitive radio is an emerging technology for efficient use of limited spectrum resources. Recently, cooperative spectrum sensing method has been proposed to overcome shadowing and fading of wireless channels. In this paper, we investigate optimum number of secondary users in cooperative spectrum sensing using adaptive threshold. Each secondary user calculates optimized threshold based on distance between primary user and each secondary user. By considering detection performance and efficiency, we derive optimum number of users in cooperative spectrum sensing. Through analysis and simulation, it is shown that cooperative spectrum sensing performance is improved under the proposed scheme as opposed to the conventional scheme.