Analysis of OFDM in the presence of frequency offset and a method to reduce performance degradation

An orthogonal frequency division multiplexing (OFDM) system is sensitive to frequency errors, causing intercarrier interference (ICI) among subcarriers. We analyze the performance degradation of an OFDM system due to frequency offset errors and propose a new ICI cancellation method to reduce the effect of frequency offset errors. The main idea is to map each data symbol a_k which is to be transmitted onto a pair of non-adjacent subcarriers k and (N-1-k), with weightings +1 and -1, other than to a single subcarrier. The carrier-to-interference ratio (CIR) of the proposed method is better than that of normal OFDM by an amount between 10 dB to 30 dB. This method has another advantage of the frequency diversity effect in the multipath fading channel. This study shows that the proposed method performs better than the previously described self-ICI cancellation method for a small value of frequency offset