Channel Estimation and Windowed DEF for OFDM with Doppler Spread

Multicarrier systems are seriously affected by time-varying frequency-selective channels. Recently, windowing and decision-feedback equalization (DFE) have separately been proven to boost the performance of minimum mean-squared error (MMSE) block equalization, while maintaining a very low complexity by capitalizing on a band LDL factorization. This paper jointly considers receiver windowing and DFE, as well as the impact on the performance of a pilot-based frequency-domain channel estimation technique that relies on a basis expansion model (BEM) approach. We show that the combination of windowing and DFE still allows the use of a low-complexity band LDL factorization. Therefore, we can further improve the BER of OFDM systems affected by severe Doppler spread, while preserving linear complexity in the number of subcarriers