A simple joint estimation-detection technique for OFDM systems

In this work a simple approach for the joint estimation-detection in a frequency selective severe fading environment of OFDM signals adopting PSK constellations is presented. A linear predictor of suitable order is adopted for the channel estimation in the frequency domain. The predictor coefficients are estimated on the basis of a sample estimation of the autocorrelation of the channel frequency response, aided by a preliminary differential decoding, in a blockwise manner. The detection technique proposed here is based on a simple tree search where a small number of best survivor paths are maintained at each step. Despite the simplicity of above detection approach, the simulation results show its effectiveness when the number of carriers is sufficiently high. Appealing features of this method are that it does not rely on any detailed model of the fading channel and that the channel coefficients are allowed to change independently in correspondence of different blocks of OFDM symbols.