Research On Cognitive Radio Spectrum Switching Technology

Since twenty-first Century, the wireless communication technology has got great development. With the constantly updated technology, and people are enjoying the convenience of the reform. As we all know, however, the wireless spectrum resource as other resources are limited, and with the spectrum utilization rate is not high, the objective factor, the development has been more and more restricted communication technology. In order to alleviate this contradiction, emerge as the times require cognitive radio technology.Cognitive radio technology can through intelligent cognitive, rational learning, accurate decision-making and scientific allocation, in order to achieve the authorized spectrum resource utilization. Spectrum hole not occupied by the technology of dynamic detection in the surrounding environment, provide the cognitive user access, when an authorized user access, the cognitive user and repeat this process, by this way can improve the utilization of spectrum resources, the contradiction between the increasing traffic demand and lack of the spectrum resources become possible. Therefore, research on cognitive radio technology, become a hot and difficult research areas in wireless communications in recent years.This paper first introduces the background, basic concept, key technology and research status of cognitive radio technology. Then the spectrum Handoff Technology for cognitive radio is analyzed, the spectrum handoff scenario is described, the key technology and existing a few basic models are introduced, finally the paper introduces the multi-objective decision theory. In the third chapter, this paper presents a fuzzy AHP based on channel ordering scheme, multiple parameters for this algorithm considering channel quality index, QoS index and demand continued effectiveness index, analysis of the channel sorting scheme for cognitive user switching process, to provide a prerequisite for spectrum handoff. And then through a series of computer simulation, proved that this strategy improvement. In the fourth chapter, this paper designs a kind of spectrum handoff method based on fuzzy controller. The control system through fuzzy multilevel design, can delay index improve system, and significantly reduce the switching frequency of cognitive users, the simulation experiment verified.