Orthogonal Frequency Division Multiplexing (OFDM) is a special form of multicarrier modulation (MCM) technique, where a single data stream is transmitted over a number of lower rate subcarriers. OFDM provides high spectral efficiency, robustness in multi path propagation environments and capability to deal with Inter Symbol Interference (ISI).
Channel estimation is a critical problem in coherent OFDM systems, and the various estimation techniques with different pilot arrangements have been investigated. A two dimensional pilot assisted channel estimation algorithm for wireless OFDM communication systems using Least Mean Square (LMS) estimation technique is investigated. Algorithm performance in terms of Signal to Noise Ratio (SNR) versus Bit Error Rate (BER) for different severe frequency selective fading channels including Rayleigh, Log Normal and Two-Ray Rayleigh fading channel models is evaluated. Performance of actual and estimated channel coefficient envelops under different Signal to Noise Ratio is also computed. The results show that algorithm performs better especially with high SNR value.
