Research And Implementation Of Mobile Satellite Channel Characteristic Simulation

In satellite mobile communication, the communication quality of transmitter andreceiver is affected by the channel time-varying characteristics. In order to offer reliableand efficient service, the study of channel transmission characteristics in communicationsystem is of great significance. Based on the analysis and research of land mobile satellitechannel measurement and satellite mobile communication model, this paper discusses thecharacteristics from large scale fading, small scale fading and Doppler effect three aspectsby qualitative and quantitative analysis respectively. And the propagation channel can bedivided into two parts: the space propagation and the terrestrial propagation. Then weestablish the channel model, which is called general configurable channel model. Themodel can achieve a variety of environment simulation, it can not only describes delay,attenuation, Doppler effect, fading characteristics, but can be controlled by parametersconfiguration to carry out broadband and narrowband channel switching, symmetric orasymmetric power spectral switching, and many other functions.On the basis of general configurable channel model, this paper designs the satellitechannel simulator, and gives the mathematical derivation and simulation of the keyalgorithm. To estimate Doppler frequency shift of real satellite communication environment,the paper proposes a geometric algorithm of LEO Doppler-time, which adapts to differenteccentricity. The algorithm simplifies complexity, guarantees the estimation precision andalso improves the computational efficiency. Besides, this paper proposes an algorithm ofdouble-end truncated power spectral for land mobile satellite channel. This algorithm cansimulate the channel environment with asymmetric power spectrum, which greatlyincreases the range of application of the channel simulator.At the end of the paper is hardware implementation of the satellite channel simulator.The simulator is based on RF interface, but the mean algorithms are on the FPGA. So thepaper focuses on the on-chip algorithms of each module, making simulation and verificationof the system. Through the comparison and analysis, the satellite channel simulator isverified correctly by the results of the test.