Research Of Carrier Frequency Offset Synchronization Algorithm For Short Burst Communication System

Short burst communication system has the adcantages of anti-interference and anti-capture,which is widely used in satellite,military,deep space exploration,high speed mobile communication etc.In these communication systems,information can transfer at higher data rate due to the application of efficient modulation and encoding methods.A possible large Doppler frequency shift results in carrier parameter offsets between the transmiter and the receiver.In the low SNR communication environment,the high accuracy carrier synchronization has vital influence on communication performance.Therefore,it is a key that how to implement carrier synchronization of higher estimation accuracy and wider estimation range with limited information.Firstly,we concentrate on the principles of some traditional synchronization methods,simulations are carried out to analyse estimation range,accuracy,complexity and applicable conditions for each method.Secondly,we analysis the FFT algorithm's principle,advantages and disadvantages,contrast FFT and its improved algorithms.Then,on the basis of the above research and analysis,we combine short burst communication systems' characteristics with the requirements of its applicable environments,a joint synchronization algorithm is proposed which is applicable to short burst QPSK modulation system in AWGN channel.The joint algorithm used M&M as coarse estimation to make sure the large estimation range,and twice cross correlation as fine estimation to garantee higher accuracy.Theoretical analysis and simulation results show that the algorithm has widely estimation range near to ?45% of symbol rate and accuracy near to perfect synchronization.Lastly,considering Turbo encoding system,we introduce the principle of Turbo code and some simulations are carried out to analyse the factors that will effect decoding performance.We also design a joint algorithm that combine M&M's advantage with cross correlation.The simulation results show that the algorithm we proposed can fulfill the requirement of Turbo decoding and keep the estimation range as wide as ?45% of symbol rate.Moreover,the algorithm has low computation complexity that is applicable to short burst communication systems.