Research On The Channel Estimation Technique For OFDM System

As a multi-carrier modulation (MCM) technique, the orthogonal frequency-division multiplexing (OFDM) has many advantages such as mitigation of multi-path distortion, low-cost of frequency-domain resource, the strong ability of the restrain of ICI, and so on. So it is widely studied in recent years. The technique of channel estimation is one of the most important techniques in OFDM system.The principle and main techniques of OFDM system are introduced in this paper firstly. Subsequently, the author summarizes the channel estimation technique for OFDM systems.Then, a low-complexity ML OFDM channel estimator is proposed. It relies on a deterministic model (i.e., no statistical information on the channel) that takes the finite delay spread of the channel into account, which is linked to the frequency correlation of the channel. Our ML estimator can be interpreted as a translation of some initial estimate of the frequency response of the channel to the time domain, followed by a linear transformation of this channel impulse response, and retranslation to the frequency domain. This interpretation leads to low-complexity algorithms, derived by combining the partial (I) FFTs involved and a small weighting matrix.