Cognitive Radios Based Research Of Key Techniques In Satellite Communication And Routing

With the rapid development of satellite communications,more and more users,the influx of business among satellite communications network,result in network resource constraints,the most serious among witch is the lack of spectrum resources,which has become one of the largest bottlenecks in satellite communication development.Proposed cognitive radio technology,greatly alleviate this conflict.It enables user's awareness through cognitive sensing access to the main communication channel,improve the utilization of the spectrum of the original system and provide more cognitive users with a secondary communication opportunity simultaneously.In cognitive radio,among the most important core technology are cognitive routes and spectrum sensing technology.At present,from domestic and international field,many spectrum detection methods have been proposed within a number of possible options,such as energy detection,matched filter detection,stable and feature detection loop,collaborative spectrum sensing,etc.,but most applications are still concentrated in the detection of terrestrial wireless communications.This advantage of cognitive radio spectrum efficiency is crucial to the scarcity of resources for satellite communications,therefore,cognitive radio technology in satellite communications has become one of the hot research area.Meanwhile,the combination of cognitive routing technology,mobile satellite communication systems and terrestrial wireless communication systems can expand the range of applications of cognitive radio technology,while improving overall system performance.This thesis mainly focuses on a study of cognitive radio technology used in mobile satellite communications network infrastructure and terrestrial wireless communications.The thesis based on the study of traditional cognitive radio spectrum detection method on terrestrial wireless communications,from cooperative spectrum sensing,cognitive routes and energy efficiency control,focuses on the mobile satellite communications system using cognitive radio technology.The main innovation of this thesis and research work are as follows:1.Research on cognitive radio and satellite communication features,this thesis proposes a LEO combined cooperative spectrum sensing algorithm on the basis of satellite and ground traditional spectrum detection algorithm,combining test results with LEO collaborate detect.Simulation results show that the proposed algorithm can effectively improve the detection accuracy of the spectrum,communication quality assurance of the primary user while providing more access opportunities for cognitive users.2.Based on the cognitive radio spectrum sensing and mobile satellite communication system architecture and mobile communication network,this thesis presents a cognitive communication network solutions combined with satellite and terrestrial communication system.In the network,terrestrial wireless communication system regards as a first communication system,while the satellite communication system regards as a second communication systems,using cognitive spectrum in ground communication network as assisted communication.Meanwhile,in the process of switching the route,this thesis proposes the fast lookup h ash table based spectrum allocation algorithm.Simulation results show that the proposed scheme can effectively guarantee the quality of primary user in ground communication,while maintaining the overall system throughput.3.Based on the research of terrestrial cognitive energy allocation scheme,this thesis proposes the maximum idle time of primary user registered channel based energy efficiency algorithm.And compared with the maximum energy allocation algorithm,the results show that the proposed algorithm can effectively improve the energy efficiency under the limited threshold of the primary user interference,providing better conditions for energy awareness communications.