Timing And Frequency Synchronization Algorithm For OFDM System

Orthogonal frequency division multiplexing (OFDM) has become the keytechnique in broadband wireless access and the next generation (Beyond 3G) mobilecommunication system. Extensive attentions have been paid to OFDM due to its highspectral efficiency, high data rate and well anti-multipath ability. The orthogonalmulticarrier modulation, which is the main character of OFDM, determines that it isverysensitive to both timing synchronization error and carrier frequency offset. So it isimportant for OFDM system to obtain accurate symbol timing and carrier frequencysynchronization, and now synchronization in OFDM has become a hotspot in theresearchofmoderncommunication.In this paper, the evolution history of OFDM system is reviewed, and thefundamental principles in OFDM are briefly introduced. After analyzing the effects ofsynchronization errors to the system performance, training symbol based joint symboltiming and carrier frequency synchronization algorithm is introduced and discussed indetail.Thesystemsimulationsandperformanceanalysesaremadetoeachalgorithm.As to training symbol based algorithms, after analysis of training symbol, a newsynchronization algorithm is proposed for orthogonal frequency division multiplexing(OFDM) systems which can get impulse response timing curve. The proposed methodnot only can overcome the shortcomings of the plateau in Schmidl algorithm, but alsoeliminate the side-peak in Park timing algorithm. MATLAB Simulation results showthat the proposed algorithms symbol timing synchronization performance is exacterthan that by general arithmetic using training symbol. And its carrier frequencysynchronizationperformanceisasgoodasgeneralarithmetic.