Study On Channel Estimation Algorithms For OFDM Systems

Orthogonal frequency division multiplexing (OFDM), with the advantage of robustness against multipath delay spread, high bandwidth efficiency, and simple hardware implementation, etc., has gained increasing interest in recent years, and is a promising candidate for becoming the key technology for the fourth generation mobile communication system. Channel estimation is a research focus; it is the fundament of coherent detection, demodulation and equalization.In this paper, based on the introduction of fading channel, the basic principle and key technologies of OFDM system are analyzed. Furthermore the channel estimation techniques and methods based on pilot and subspace (blind) in OFDM are discussed in detail. Channel estimation based on the pilot symbols has merits of fast convergence speed and low computational complexity, but the insertion of the pilot symbols wastes the system resource and reduces the system data transmission efficiency. The blind estimator does not need the pilot symbols and save the bandwidth, but it has the disadvantage of slow converage speed and large computational complexity. In the end, the analysis and comparisonof these algorithms is made by computer simulation.