Adaptive BLAST decision-feedback equalizer for MIMO-FBMC/OQAM systems

Filter bank-based multicarrier modulation (FBMC) using offset quadrature amplitude modulation (OQAM), known as FBMC/OQAM, provides an attractive alternative to the conventional cyclic prefix-based orthogonal frequency division multiplexing (CP-OFDM), especially in terms of increased robustness to frequency offset and Doppler spread, and high bandwidth efficiency. However, channel equalization in FBMC/OQAM is a nontrivial task, mainly because of the fact that the subchannels are no longer flat, in general. In multiple-antenna (MIMO) time-varying systems, equalizing the channel becomes even more challenging. This paper presents an adaptive T/2-spaced decision-feedback equalization (DFE) algorithm for MIMO-FBMC/OQAM systems, that is both computationally efficient and numerically stable. Its structure follows the V-BLAST idea and the algorithm is applied in a per subcarrier fashion. Simulation results are reported that demonstrate its effectiveness in time-varying MIMO channels with high frequency selectivity.