Low-complexity ISI-free region detection for OFDM systems in high-mobility fading channels

In this paper, a low complexity algorithm for ISI-free region detection in OFDM system is proposed for high mobility fading channels. In fact, Manhattan distance instead of the cosine similarity is employed as the symbol-by-symbol correlator to detect the region, and therefore the multiplication complexity is reduced from polynomial time to zero, while the accuracy is kept and even better in the case of low SNR. One application of the detection is on symbol timing without increasing redundancy, and another application is of intercarrier interference (ICI) elimination. The results of this paper are verified by computer simulation with doppler shift for high speed mobility.