This letter proposes a novel intercarrier interference (ICI) mitigation method for OFDM in time-varying multipath channels. By splitting an OFDM symbol into sub-symbols, ICI may be relieved but with price of increased inter-subsymbol-interference (ISI). The induced ISI is then cancelled by a linear filter with the use of null subcarriers. Simulations show that the proposed method may effectively mitigate ICI while improving OFDM with enhanced reliability against high Doppler spread.