Windowed DFT-Based OFDM Channel Estimation by Adding Virtual Channel Frequency Response

The energy leakage from non-sampled-spaced multipath time delays results in the degradation for the discrete Fourier transform (DFT)-based channel estimation method. The leakage effect escalates when virtual subcarriers are reserved to ease the filter requirements in OFDM systems. To alleviate the leakage effect, a novel windowed DFT-based channel estimation method by adding virtual channel frequency response (VCFR) is proposed. A new window function and a linear interpolation-based estimated VCFR are adopted in the proposed method to achieve better performance compared with other DFT-based channel estimation methods. The proposed method is insensitive to the length of the unused frequency band. The effectiveness of the proposed method to combat the leakage effect is examined under various standard channel models. The simulation results have shown the proposed method outperforms especially when the number of virtual subcarrier is large.