Research And Implementation On OFDM Synchronization Technology

OFDM has been being used widely as a multi-carrier communication technology.The orthogonality between the OFDM subcarriers and the overlapping between thecarrier spectrums can make the system have the high bandwidth utilization; multipathanti-diffusion is mainly reflected by the OFDM guard interval, in order to avoidinter-symbol interference (ISI). Based on these two major advantages, OFDM iswidely used in multipath wireless communication and frequency selective channel. Inrecent years, the rapid digital audio/digital video broadcasting (DAB/DVB), wirelessLAN and the Long Term Evolution (LTE) system are all using OFDM technology.This paper starts as the study of synchronization, based as portable wireless videocommunication system, aims to design and realization of a portable wireless videocommunication system synchronization scheme. Firstly, it gives the analysis of thetiming and frequency offset affecting the performance of OFDM system, then talks thesynchronization algorithms. Secondly, it gives the design of synchronization schemefor Portable Wireless Video Communication System, and simulation it by Matlab. Andthe simulation result shows that the Timing Estimate Point are all passed, and thefrequency estimate MSE can be little than0.0004, thus, they are all pass.Finally, the synchronization module for Portable Wireless Video CommunicationSystem is implemented by circuit. The hardware implementation process is as follows:Firstly, the timing synchronization and carrier frequency synchronization moduleshould be devided as some circuit sub-modules, and taking the fixed-point arithmeticsimulation by Matlab, in order to determine the width of the signals which are involvedin computing. After determining the width, the timing synchronization module andcarrier frequency synchronization module will be designed based on RTL Level inVerilog HDL language, and then the functional simulation based on Modelsim showsthat the circuits’ functions meet the requirement. Finally, both the timingsynchronization and carrier frequency synchronization circuits are tested bydownloading in FPGA, which is Spartan VI XC6SLX45, manufactured by Xilinx. Thecircuit can be implemented in FPGA, and using the Chipscope which is a tool integrated in ISE can show the waves. Thus, the timing synchronization and carrierfrequency synchronization circuit are all correct.