Performance Analysis Of OFDM Channel Of Ka Band Satellite Communication System

In a stationary satellite communication system, the existing available spectrum resourcesare limited, ultra wideband high speed transmission must use higher frequency. The basic isthe use of Ku band broadband satellite communications services, so that Ku band applicationalready very crowded, so the recent ultra wideband high speed transmission basic is a Kaband satellite communication. Ka band satellite communication is presented in this paper, onthe basis of to a new generation of airborne Ka band satellite communication as the practicalsignificance, research status at home and abroad are introduced, Between in the field ofairborne satellite communication research in China is not very mature, there is rain in airborneKa band satellite communication failure effect, and the problem of doppler effect toperformance analysis was carried out on the satellite channel.With the rapid development of DSP, WINMAX, smart antenna, etc., in the realization ofultra wideband high speed transmission, multicarrier modulation (OFDM) technology iswidely used for its obvious technical advantages, the technology has become the darling ofthe wireless transmission field. Its bright high data rate transmission, anti-multipath,resistance to channel fading, adaptive transmission, anti-interference, ultra wideband, highchannel utilization characteristics determine the possibilities of it will be a smoothtransmission. This article will focus on airborne Ka band satellite communication, atheoretical analysis of the problems existing in the first rain failure distribution fitting, andfind out the optimal rain failure distribution function, and carries on the channel estimationbased on OFDM modulation, find out the optimal pilot scheme.It is investigated in this paper, the first half and Ka band satellite communication systemof rail link features, first by Ku/Ka band down link rainfall attenuation value transformationfor changchun area rainfall data, analysis of strong rainfall period of satellite communicationlink, and then use the ITU-R on rainfall and least square method curve fitting, to verify theeffectiveness of its predictions, finally, the rainfall attenuation change rate are studied, based on the logarithmic normal distribution and the power distribution of the simulation, theoptimum distribution channel rain fade out.In the second part mainly studied the way of OFDM based on pilot channel estimationtechnology, mainly includes pilot insertion method and the basic algorithm of channelestimation. Pilot insertion way mainly includes the massive pilot, comb pilot and scatter pilot.Pilot point or LMMSE algorithm based on the LS algorithm of channel estimation and datapoints using interpolation algorithm of channel estimation. In MATLAB simulation, the mainrain failure channel for the LS and the comparison of LMMSE algorithm, under different pilotfrequency interval block pilot channel estimation, comb pilot channel estimation and pilotchannel estimation, and get the optimum Ka band satellite communication way of pilot.