The Synchronization Algorithm Research On The OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) technology is one kind of effective high-speed multicarrier transmission technology. Because it has the very high frequency spectrum utilization efficiency and strong resistance to multipath fading ability for decades and so it becomes one of the main technology of mobile communication. But in the current mobile communication the application of technology OFDM still needs to be improved and optimized. The OFDM system for the synchronous error is very sensitive, and it becomes main threshold to limit the rapid development of synchronization technology of the OFDM. Therefore for OFDM system the accurate symbol timing estimation and carrier frequency offset estimation are very important.In this paper, at first the history of development and characteristics about OFDM synchronization technology are in detail, also the fundamental on OFDM synchronization technology is recommended, including OFDM system framework, design and choice of OFDM basic parameter. Secondly OFDM synchronization technology is made the detailed analysis, which mainly includes OFDM synchronization introduction, OFDM system synchronization technology, the synchronous deviation to the influences of OFDM system and some methods to realize synchronous. Based on the analysis of these aspects to emphasize the importance of OFDM system timing estimation and Carrier frequency offset estimation, then raising some estimation algorithms. Finally synchronization algorithm can be divided into two aspects:one is based on adding training sequence synchronization algorithm and the another is synchronization algorithm based on cyclic prefix. the former algorithms have Schmidl algorithm, Minn algorithm and Park algorithm, doing some improvements for the Minn algorithm; Representative of the latter algorithm is ML algorithm, on which having made some improvement when the cyclic prefix is small. Finally comparing the improvements of these two kinds of synchronization algorithm, and doing a large amount of theoretical derivation and analog simulation,which demonstrates that the improved algorithm of Minn has better performance under multipath channel, and the timing estimation of the improved ML algorithm is more accurate.