The Study On The Technique Of Synchronization In OFDM System

At first, the principle, properties and key technology are described simply, some Classical synchronization methods are enumerated. The effect of synchronization error of an OFDM system is discussed in detail. This paper presents an overview of OFDM technique and its implementation scheme and making use of MATLAB to simulate the transmission performance of a Variable Bit Rate OFDM in 802.11a standards. The study show that symbol timing offset and sampling frequency offset would introduce inter-symbol interference, frequency offset of carriers would result in inter carrier interference. So, in an OFDM system, finding the symbol timing, the carrier frequency offset, and the sampling rate offset the receiver is important in the recovery of the signal. Second, timing and carrier frequency synchronization has been studied in this paper. OFDM timing algorithm is improved in this paper, and the modified algorithm overcome the shortcomings of the phantom which result in ambiguity of timing estimation and multi-peak would occur in the shortcomings of the conventional method. As autocorrelation is used, timing recovery of the proposed is robust to carrier frequency offset and multi path. The timing offset of frame and symbol can be estimated simultaneously in time domain, thus reducing the complexity of timing synchronization. The modified algorithm is simple and the overhead is small, only one training symbol is used, the low overhead and fast algorithm is very suit to synchronizing of a burst OFDM system.