A Novel Two-stage Design Scheme of Equalizers for Uplink FBMC/OQAM-based Massive MIMO Systems

TL;DR

This paper introduces a two-stage equalizer design for FBMC/OQAM-based massive MIMO systems that enhances interference mitigation and SINR performance while maintaining manageable complexity.

Contribution

It proposes a novel two-stage equalizer scheme that improves interference removal and SINR in massive MIMO FBMC/OQAM systems without requiring statistical CSI.

Findings

Enhanced SINR performance demonstrated in simulations.

Almost eliminated interference with finite BS antennas.

Reduced implementation complexity compared to prior methods.

Abstract

The self-equalization property has raised great concern in the combination of offset-quadratic-amplitude-modulation-based filter bank multi-carrier (FBMC/OQAM) and massive multiple-input multiple-output (MIMO) system, which enables to decrease the interference brought by the highly frequency-selective channels as the number of base station (BS) antennas increases. However, existing works show that there remains residual interference after single-tap equalization even with infinite number of BS antennas, leading to a limitation of achievable signal-to-interference-plus-noise ratio (SINR) performance. In this paper, we propose a two-stage design scheme of equalizers to remove the above limitation. In the first stage, we design high-rate equalizers working before FBMC demodulation to avoid the potential loss of channel information obtained at the BS. In the second stage, we transform the high-rate equalizers into the low-rate equalizers after FBMC demodulation to reduce the implementation complexity. Compared with prior works, the proposed scheme has affordable complexity under massive MIMO and only requires instantaneous channel state information (CSI) without statistical CSI and additional equalizers. Simulation results show that the scheme can bring improved SINR performance. Moreover, even with finite number of BS antennas, the interference brought by the channels can be almost eliminated.