Downlink per-user multi-streaming for FBMC/OQAM based multi-user MIMO with highly frequency selective channels

This paper provides solutions for per-user multistream transmissions in FBMC/OQAM based multi-user MIMO downlink systems under highly frequency selective propagation conditions. A signal-to-leakage-plus-noise-ratio (SLNR) based metric is proposed, and it is tailored for the downlink of FBMC/OQAM-based multi-user MIMO settings. Then at the base station, per-subcarrier fractionally spaced multi-tap precoders are computed based on this metric to mitigate the multi-user interference (MUI), the inter-symbol interference (ISI), as well as the inter-carrier interference (ICI) and to map the multiple data streams of each user to the transmit antennas. With the base station carrying most of the computational load, each user terminal only employs a zero-forcing (ZF) based one-tap spatial equalizer to recover the desired streams. Simulation results show that the proposed SLNR based precoding scheme achieves satisfactory performances in various multi-user MIMO downlink scenarios. It significantly outperforms the existing algorithms that require the channel on each subcarrier to be flat fading.