The Research Of OFDM Synchronization Technology Based On Broadband Satellite Communications System

Broadband satellite communication has become one of the new hotspotscommunications, the future of communication is based on multimedia communicationsand broadband. Broadband satellite communications is vulnerable to rain and otheratmospheric disturbances, poor channel characteristics and spectrum resourceconstraints. OFDM technology has a strong anti-interference ability and highbandwidth efficiency which can solve these problems, and thus suitable for satellitecommunication systems to achieve the high-speed transmission. However, OFDMtechnology is based on the advantages of orthogonal sub-carriers and thesynchronization error which is extremely sensitive to multipath effects in the satellitechannel, the Doppler shift will cause the synchronization deviation and the main papermobile satellite OFDM system synchronization techniques.This paper describes the characteristics of satellite mobile communicationchannels, and proposes channel model simulation of this article. Focuses on the effectsof multipath and Doppler shift and selects the next suburban environments broadbandmobile satellite communication channel model as this paper simulation environment.Then from OFDM system implementation process is combined with satellite channelcharacteristics, focusing on the reasons for the deviation generated synchronization inOFDM systems, theoretical analysis and simulation timing deviation and frequencydeviation effects on OFDM systems. Training sequence based on OFDMsynchronization method, first, the timing synchronization, and the simulation analysisunder the principle of the rural environment, a satellite channel and performance of theMinn and Schmidl&Cox method, improves training sequence based on this structure,the use of conjugate symmetry achieve timing estimates, the timing sharp peak, so thetiming synchronization accuracy has been greatly improved. Frequency synchronizationis divided into fractional frequency offset estimation and two integer frequent offsetestimation process, generally performed first fractional frequency offset estimate, thencorrected to eliminate ICI, then the integer frequency offset estimate.This article studies the frequency synchronization algorithm Schmidl&Cox, and proposes a multiple valuation averaged fractional frequency offset correction methodbased on this algorithm, the estimated performance is more accurate. The research andperformance simulation for algorithm of Minn. Moose algorithm and the impact of thepilot sequence synchronization algorithm parameters on the performance of analysisand simulation, frequency offset estimation algorithm based Schmidl&Cox integerfrequency offset estimation algorithm for improving ideological and given an integerarithmetic comes from the Moose. Finally, the training symbol timing synchronizationstructure adopted, proposed frequency offset estimation method, the receiving end ofthe demodulated signal BER conjugate relationship-based fractional frequency offsetestimation methods and new integer simulation, the performance of the algorithmfrequency synchronization consistent with Minn algorithm.