The Study Of Modeling And Simulation Of Satellite Mobile Communication Fading Channel

Monotonous terrestrial mobile communication means hasn't been able to satisfy people's demand of transmitting communicate information whenever and wherever they want.An effective approach to fulfill human such demand is to combine satellite mobile communication system,a complementary system,with terrestrial mobile communication system.In mobile satellite communication system,research on satellite mobile communication channel,the information transmission medium,is very necessary.In order to ensure the reliability of information transmission and the reasonable planning and design of the system,communication technology must match with channel characteristics,and using effective channel model to simulate and verify the validity and reliability of various communication technologies.In view of the deficiency of the existing satellite mobile communication fading channel model under the specific scene in the description of the actual channel,this paper has improved and modified C.Loo channel model,uses Sum of Rician Sinusoid to realize channel model,and puts forwardthe modified C.Loo channel model with superior performance.Firstly,this paper briefly introduces the radio wave propagation,the Doppler power spectrum and the distribution of commonly-used probability,does some research on the first and second order statistics that are used to describe the performance of channel model,and carries out theoretical deduction of C.Loo channel model for statistical characteristics.On the basis of the research,this paper studies the modeling and simulation method of channel.Then,this paper adopts Sum of Rician Sinusoid to construct the colored Gauss noise random process and theoreticaly deduces the five kinds of parameter calculation methods of Sum of Rician Sinusoid--method of equal distance,method of equal area,Monte Carlo method,minimum square error method,accurate Doppler expansion method--based on two kinds of power spectrum density.After simulation and comparison three performance index,mean square error,frequency of autocorrelation function of the Doppler shift factor,Doppler diffusion factor,of the above five kinds of methods,this paper selects accurate Doppler expansion method which has superior performance to conduct following study.Finally,on the basis of the chosen parameter calculation method,this paper improves C.Loo channel model and gets the modified C.Loo channel model,aiming at getting rid of problems of the existing C.Loo channel model,such as large Doppler frequency shift of multipath components and ignorance of diameter components on Doppler frequency shift.The modified C.Loo channel model ustilizes limited Doppler power spectrum to constraint two real narrow-band Gauss random process and introuces correlation between them.At the same time,it also introduces Doppler shift into diameter components,establishes the modified C.Loo channel model,and carries out simulation in the earth synchronous orbit Inmarsat satellite rural environment L band with 15 degrees elevation.A comparison between the gained stastistics characteristics of the previous modeling and simulation and the corresponding statistics features of measured data proves that the modified C.Loo channel model is more similar to real channel than C.Loo channel model.