Research Of A Decision Fusion Scheme With Quantization In Cooperative Spectrum Sensing

With the rapid development of wireless communication, communication system of the increasing demand for the wireless spectrum, spectrum resource is becoming more and more nervous. The lack of available spectrum resources has become one of the biggest bottlenecks in the development of wireless communication. Cognitive radio as an effective intelligent radio technology to improve spectrum utilization, can solve the problem of the development of wireless communication technology.Spectrum sensing is the key of cognitive radio, and the premise of achieving other technology of cognitive radio. In this paper, the problem of how to improve the sensing performance while minimizing the required transmission overhead of co-operative spectrum sensing is researched. A decision fusion scheme based on2-bit quantization and a decision fusion scheme based on improved double-threshold detection is proposed. Main content as follows:1. The paper introduces the significance and theoretical basis of cooperative spectrum sensing technique, and research the decision fusion scheme in cooperative spectrum sensing.2. A new softened hard combination scheme with2-bit quantization of observed energy for each user is proposed when the reporting channel is Rayleigh fading. We discuss the effect of the SNR, the number of cognitive users and sensing time on detection probability, false alarm probability and throughout in this scheme, and compare with soft combination and hard combination.The sensing performance of2-bit quantization of cooperative sensing scheme is researched and compared with soft combination and hard combination.3. Based on the traditional double-threshold cooperative sensing scheme, an improved double-threshold cooperative sensing scheme is proposed. Theoretic analysis and computer simulation show that the proposed scheme can improve the detection performance and reduce the overhead significantly. So the improved double-threshold cooperative sensing scheme can achieve a good trade-off between detection performance and system complexity.