Two-Step Doppler Estimation Based on Intercarrier Interference Mitigation for OFDM Radar

In the presence of intercarrier interference (ICI), conventional orthogonal frequency-division multiplexing (OFDM) radar exhibits serious performance degradation when estimating the Doppler frequency of a target. In this letter, a two-step Doppler estimation scheme is proposed for OFDM radar. In order to mitigate ICI, a sequence with a good correlation property is assigned to the subcarriers to generate an OFDM signal, and oversampling is applied to the received OFDM signal in the frequency domain. Then, Doppler estimation with coarse and fine estimating steps is performed to achieve accurate Doppler estimation. Also, it is shown that the proposed scheme enables parallel calculation of correlation values to reduce the latency and enlarges the Doppler estimation range by eliminating Doppler ambiguity. Finally, simulation results are provided to show that the proposed scheme outperforms the conventional scheme with slightly increased computational complexity.