Using zero padding for robust channel Estimation in SEFDM systems

In spectrally efficient frequency division multiplexing (SEFDM) systems, the subcarrier spacing is compressed below the orthogonality limit, to enhance the bandwidth utilisation with respect to orthogonal frequency division multiplexing (OFDM). This gives rise to inter-carrier interference (ICI) between the subcarriers and the received pilots are affected by self-ICI combined with multipath effects. Therefore, channel estimation becomes more challenging. In this work, a frequency-domain channel estimation approach is proposed for SEFDM systems, which replaces the commonly used cyclic prefix by padded zeros (ZP) for the transmitted symbols. Advantageously, the multipath components that appear in the ZP part are used to enhance channel estimation, as verified by modelling and simulation results of this work.