DFT-based channel estimation in 2D-pilot-symbol-aided OFDM wireless systems

An efficient channel estimation algorithm for OFDM in wireless applications has been proposed. Two-dimensional pilot-symbol assisted modulation (2D-PSAM) is employed in coherent OFDM for channel estimation and it is based on inserting known symbols spreaded throughout the 2D time-frequency grid. These scattered symbols are employed to perform an estimation of the channel's frequency response. At a first stage, if certain requirements are fulfilled, channel estimation in frequency dimension can be carried out with an efficient DFT-based algorithm, which provides an accurate estimation at time positions where pilot symbols are included. In the second step, linear interpolation is performed in the time direction. This scheme has been proven to be very successful in multicarrier HF communications systems.