Research And Improvement Of Distributed Radio Frequency Spectrum Allocation

Along with the rapid development of wireless communication services, the demand for spectrum resources has grown with the sustained economy and the quality of spectrum has been allocated exhaustedly. However, the utilization of the licensed spectrum is very low. The reason of this contradiction is that the inherent spectrum is allocated irrationally and that the authorized spectrum has been wasted when the band was unused. Therefore, cognitive radio technology (CR) is proposed, in order to solve the outstanding contradictions. CR can sense the free spectrum resources from the perception of space and time up and use these resources in a complex spectrum environment, so as to achieve the limited spectrum resources. Allowing secondary users expropriate the spectrum of the primary user when they don’t disturb the primary user’s normal traffic. It can dynamically use the spectrum and improve the spectral utilization greatly.This thesis is to research the spectrum resources algorithm of the CRN technology based on the batches spectrum allocation model. In this paper, the content of the work and some results are mainly attributed as follows:First, we give a comprehensive introduction to the study of the basic concept of cognitive radio technology and the traditional spectrum sensing technology. Then we elaborate function and feature of the cognitive radio technology and the spectrum sensing technology, which includes several key technology of the cognitive radio technology and a variety of spectrum sensing techniques.Second, based on graph coloring theory for spectrum allocation technique, we introduced two spectrum algorithms of allocated greedy for spectrum and allocated fair for spectrum. Also we analyzed the performance of them. The distributed greedy algorithm has higher system’s throughput, but it ignores some channel fairness of secondary users. While distributed fairness algorithm consider the fairness of secondary users channel, the drawback is the expense of the system’s throughput. With graph coloring theoretical model, we established the foundation for the later mode and provide theoretical support.Third, based on the graph coloring theory, we established a spectrum model of allocation batch collaboration, which can reduce collision and conflict of the secondary user when the secondary users sense channel, in order to increase the spectral utilization. On the basis of adding energy threshold algorithm in the allocating model of collaboration in batches, it can effectively control the energy consumption of secondary user sensing the channel. Meanwhile, it can decrease energy consumption. There is to a great of benefits that can extend the detecting life cycle of system and optimize system’s performance. After simulating and analyzing, we can get a conclusion that system’s throughput (or the total amount of communication systems) has been greatly improved with the introduction of energy threshold algorithm in batches collaborative allocating model. Finally we can achieve the goal that the performance of system will be optimized.