Research On Synchronization Algorithms Of OFDM Systems

One of the requirements of next generation of wireless mobile communication system higher is to provide the transmission of the multimedia services with higher speed and wider bandwidth. In the wireless environment, the frequency resources, power and wireless fading channel limit higher data transmission. In theses years, OFDM (Orthogonal Frequency Division Multiplexing) technique has been paid more and more attention because it has strong transmission ability in wireless channels, which comes from its own parallel transmission mechanism,inherited robustness to Inter Symbol Interference (ISI) and the diversity with the multi-path channel. Meanwhile, OFDM system has very high channel utilization ratio because of the orthogonal properties among its sub-carriers.This paper introduces the emergence, development, basic working theory,characteristics and the merits of OFDM systems. In the first part, researches the theory of OFDM, and how to realize OFDM system by FFT/IFFT. Later, simulates the OFDM system by MATLAB software,researchs the effect about OFDM system by mapping, guard interval , sub-carrier and channel. Analysis the performance of timming offset,frequency offset and sampling offset in OFDM systems.This paper investid the timing and frequency offset estimation algorithms of OFDM transmission systems. This thesis studies, analyses and compares .some synchronization methods which have been proposed.Many simulations are taken, the performances are given by simulation results, and some conclusions are given. Two new methos which Based on the methos of Schmidl&Cox and H.Minna synchronization algorithm have been propsed here to estimate timming offset and discussed in detail.The result of simulations shows that the methos which we propsed are feasible and efficient to reduce the timming offset which can maintain good system performance.