Complex Coefficient Interpolation Based Channel Estimation for OFDM in Single-Frequency Networks

In orthogonal frequency division multiplexing (OFDM) system operating in single-frequency broadcasting networks (SFN), classical real-coefficient-based channel interpolation schemes are challenged by long-delay echoes. Based on the equivalence between frequency interpolating and time-domain windowing, conventional filter design methods are employed to develop a complex low pass interpolator enhancing the robustness of channel estimator against SFN long-delay echoes. The high-performance interpolator is verified in a simulated digital video broadcasting for terrestrial/handheld (DVB-T/H) receiver. The simulation results indicate that the designed channel estimator can handle the SFN echoes with more than 200 μs delay, which significantly outperforms conventional CE methods.