OFDM Symbol Timing Synchronization Research And Implementation

Extensive attentions have been paid to Orthogonal frequency division multiplexing(OFDM) due to its high spectral efficiency, well anti-multipaths and anti-frequency selective fading ability and flexible allocation of resource and noise immunity. OFDM has become the key technique in the next generation mobile communication system and broadband wireless access. As a multicarrier modulation, OFDM is very sensitive to synchronization error.Therefore,in the current field of communication,synchronization has become a hot research topic.At first, history, advantages and disadvantages and key technology of OFDM are described simply; Then introduce the basic principles of OFDM systems, including basic transmission model and mathematical signal model; the effect of various types of synchronization error has been discussed in detail, further demonstrating the importance of the synchronization in the OFDM system.Second, symbol timing synchronization algorithm has been main studied in this paper. On the basis of data assisted algorithm, two improved OFDM symbol timing algorithms are proposed.They overcome shortcomings of platform phenomenon and multi-spike phenomenon which result in timing measure vague in Schmidl & Cox and Minn’s algorithm, also with superior performance in different channels than Park’s algorithm.There just exist only one peak in the proposed algorithms, and they are based on thought of the matched filter, thus increasing the accuracy of the symbol timing synchronization.At last, the physical layer parameters and frame structure of the IEEE802.11 a standard is introduced. Several frame synchronization algorithm and symbol synchronization algorithm based on the standard have been simulated and analyzed. These two modules are carried out in the FPGA Evaluation Module, and proved the feasibility comparing to software simulation. Finally, has a joint hardware debugging with other modules of the system, and analyze the data of experiment..