Research On Spectrum Allocation And Handoff Besed On Interference Analysis In Spectrum Sharing Between Satellite And Terrestrial

With the development of communication technology and global informatization,modern life has a higher demands in communication quality,communication speed and communication load.Meanwhile,an increasing amount of user access various communication systems.The problem of spectrum scarcity is getting worse.People solve the problems and shortcomings of terrestrial communication systems by introducing satellite communication,but the problem of spectrum shortage also occurs in satellite communication.At the same time,some systems have the lisence of using the certain spectrum,but have a low using sufficiency.Therefore,through cognitive radio technology,spectrum sharing between communication networks can effectively alleviate the problem of resource shortage.This paper focuses on the technology on sharing spectrum between satellite communication and terrestrial communication,and focuses on resource management techniques in this scenario.Firstly,this paper introduces the background and research content,and analyzes the significance of cognitive radio in satellite communication.Combining domestic and foreign research and literature review,discusses the development and research derection of cognitive radio in cognitive satellite system.Secondly,this paper introduces the main research scenarios of cognitive satellite,the problems and research priorities of each scenario.Then,points out that the research scenario of this paper is the spectrum sharing between fixed satellite service and terrestrial fixed service in Ka band.The interference environment of the two systems in realizing spectrum sharing is analyzed in detail.The two systems interact with each other is introduced.Establishing the signal and interference model of satellite uplinks and downlinks respectively.Then,based on the interference analysis above,this paper studies the spectrum allocation method of cognitive satellite uplink and downlink.In the uplink,in order to avoid interference towards terrestrial systems,a power and spectrum joint allocation algorithm is studied.In the downlink,in order to solve the problem of insufficient shared spectrum resources,a satellite downlink priority model is established to study a priority-based spectrum allocation method.The Hungarian algorithm is used to achieve the spectrum allocation of the satellite communication link,so that the total throughput of the satellite system is maximized.Finally,in order to avoid interference between satellite links and terrestrial links,satellite links needs to handoff spectrum timely.Aiming at the channel selection problem in spectrumhandoff,this paper studies a target channel selection algorithm based on multi-attribute decision.In order to adapt to the changing wireless environment,this paper adopts a dynamic weighting algorithm to improve the performance and flexibility of spectrum handoff.