Channel estimation for high-speed packet-based OFDM communication systems

In orthogonal frequency division multiplexing (OFDM) based packet communication systems, it is desired to minimize the number of pilot symbols for better spectrum utilization. Also, accurate channel estimation is required for coherent demodulation of OFDM signals, particularly when modulated by multilevel modulation schemes. In this paper, we present a pilot-assisted decision-directed channel estimation technique suitable for packet transmission with relatively short OFDM symbols. Simulation has shown that our approach can save about 20% of the number of pilot symbols required in the conventional least square estimator for a situation considered in this paper.