FBMC-OQAM in doubly-selective channels: A new perspective on MMSE equalization

In many practical cases, one-tap equalizers achieve a close to optimum performance in filter bank multi-carrier modulation systems. However, if the channel is highly doubly-selective, that is, time-selective and frequency-selective, enhanced equalization methods might be necessary. In this paper, we generalize the n-tap Minimum Mean Squared Error (MMSE) equalization, proposed in literature, by also including neighboring subcarriers into the equalization process. As a reference, we also derive a full block MMSE equalizer and compare to a low-complexity interference cancellation scheme. Our investigation starts with a single-antenna system and is later extended to multiple antennas.