Multi-User MIMO with flexible numerology for 5G

TL;DR

This paper explores multi-user MIMO in 5G with flexible numerologies, demonstrating that interference between users with different numerologies can be effectively suppressed using antenna arrays, enabling diverse service support.

Contribution

It introduces a novel MU-MIMO approach with different numerologies, including separate pre-coding and FFT processing, and analyzes its performance through capacity and link-level simulations.

Findings

Inter-user interference can be suppressed with a reasonable number of antennas.

Different numerologies can be multiplexed efficiently using the proposed MU-MIMO scheme.

The approach enables flexible support for diverse 5G services.

Abstract

Flexible numerologies are being considered as part of designs for 5G systems to support vertical services with diverse requirements such as enhanced mobile broadband, ultra-reliable low-latency communications, and massive machine type communication. Different vertical services can be multiplexed in either frequency domain, time domain, or both. In this paper, we investigate the use of spatial multiplexing of services using MU-MIMO where the numerologies for different users may be different. The users are grouped according to the chosen numerology and a separate pre-coder and FFT size is used per numerology at the transmitter. The pre-coded signals for the multiple numerologies are added in the time domain before transmission. We analyze the performance gains of this approach using capacity analysis and link level simulations using conjugate beamforming and signal-to-leakage noise ratio maximization techniques. We show that the MU interference between users with different numerologies can be suppressed efficiently with reasonable number of antennas at the base-station. This feature enables MU-MIMO techniques to be applied for 5G across different numerologies.