Channel Impulse Response Order Adjustment for OFDM in SFN

In orthogonal frequency division multiplexing (OFDM) systems, channel power delay profile can be acquired by an IFFT of pilot-aided channel estimate which is used for fine timing. However, an ambiguous channel impulse response (CIR) estimate is induced by coarse timing errors. In this paper, a simple CIR adjustment algorithm is proposed to correct the CIR order which can hold with large coarse timing errors and high delay spread environment, and a modified coarse symbol timing algorithm is adopted to ensure its performance. Simulations show the timing synchronization performance is excellent even in the high delay spread environment.