ICI Reduction in OFDM by using Maximally Flat Windowing

Conventional orthogonal frequency division multiplexing (OFDM) receivers disregard oversized guard intervals. An (adaptive) Nyquist-shaped receive window could exploit signal samples in its unconsumed portion to improve demodulation. This paper presents a novel windowing scheme that optimally reduces the Intercarrier interference (ICI) resulting from frequency offset in orthogonal frequency-division multiplexing. In frequency domain, the proposed window has a maximally flat shape at all the subcarrier frequencies. A general closed-form solution for these optimal windows is derived. The simulation results shows that the maximally flat (MF) window has a much better bit error rate performance than the common raised-cosine window and the newly proposed "better than" raised-cosine window.