Research On The Key Techniques Of Orthogonal Frequency Division Multiplexing

Orthogonal Frequency Division Multiplexing (OFDM) has been one of the key techniques in 4th generation mobile communication systems due to its high data rate transmission capability with high bandwidth efficiency, flexible modulation modes and its robustness to multi-path delay. It has been used in wireless LAN standards such as DVB-T, DBA, IEEE802.11.The channel estimation techniques and timing and frequency offset estimation techniques for OFDM systems are investigated in this paper. Firstly, channel estimation techniques based on pilot arrangement are mainly introduced. Three estimation algorithms for pilot signals and seven channel estimation inner-insertion equalizer techniques are introduced. Secondly, all presented methods are analyzed and their performance curves are given based on MATLAB system simulations. The merits and defects are shown based on those simulations. Besides, a simulated IEEE802.11a WLAN channel estimator is realized based on MATLAB SIMULINK toolbox. Then, the existing timing and frequency offset estimation methods are studied and chiefly the non-data-aided blind algorithms are introduced in this paper. Finally, a new method for timing and frequency offset estimation is proposed based on several available methods. The simulation results show that the new method has higher performance and lower computation cost.