High-speed Data Transmission System In Land Mobile Satellite Chanel

With the development of satellite communication towards wide-band,high data rate transmission and high band, Ka-band satellitecommunication has become more and more popular. The research haslarge influence on the implement of satellite communication at high datarate.The land mobile satelite communication is one of the moderncommunicationtechnology and it is the important component of realizingglobal personal satellite communication, So studying the channel modelof satelite is one of the main currentresearch hotspot. This text is basedon channel model which the domestic and international expert putforward, has studied the channel modeling method of the land mobilesatellite deeply, summarized the structure of land satellite channel andlaw of the models. According to propagation characteristic of electricwave, a Nakagami statistic model of mobile satellite is proposed . TheNakagami distribution is used widely in US band mobile satellitesystem,so we applyit to Ka-band.According to the nature of weather and multi-path, we can assumethat theweather and multi-path efects on the channel are independent.Thus, we set up the complete simulating channel model of Ka-bandmobile satellite and calculate thebound of BER for BPSK modulation.Comparing the theoretical and simulatingresults, we can conclude that thesimulating model is suitable for Ka-band mobile satellite system. On thestudy of BPSK digital modulation technology for Ka-bandsatellite communication system, the fading efects on transmited signal aresimulatedand the amounts of performance degradation are diferentdepending on weatherconditions. Signal phase fading has a relativelysmall efect as compared with signalenvelope fading.So,in this paper, we apply the Turbo code to Ka-band mobile satellitesystem, simulate the BER performance and modify a SNRestimationmethod. From the simulating results, we find the estimated SNRperformance is close to that of perfect SNR. So the modified method issuitable for Ka-band mobile satellite system, and the Turbo code canimprove the performance of system.ChapterⅠintroduces the development and process of the landmobile satellite. ChapterⅡintroduces the statistical characteristics ofradio channels. ChapterⅢintroduces and compares the common landmobile satellite channels models. A Nakagami statistical model for landmobile satellite is proposed in chapterⅣand its first and secondarycharacteristics are studied and computed. Also comparisons betweenthemeasured received signals and the simulated received signals are made.ChapterⅤintroduces an application of using Chapter model as ashadowing model in Ka-band models. ChapterⅥsummarizes thedissertation and the hope and expectation are proposed.The characteristics of the channel are important for the systemperformance of the Ka-band mobile satellite communication. In the paper,we study the characteristicof the communication channel, and suggestedthe statistic and simulating channelmodel by developing the propagationcharacteristics and the measured results of thechannel. It is shown that thechannel which is afected by weather is in accordancewith Gauss distribution and the channel of ground is modeled asNakagamidistribution.