Pilot Decontamination for Massive MIMO Network with UAVs

TL;DR

This paper addresses the severe pilot contamination issue in massive MIMO networks caused by UAVs with LoS channels, proposing a low-complexity distributed scheme that significantly improves SINR in uplink and downlink.

Contribution

It introduces a novel pilot decontamination method leveraging full-dimensional beamforming and angle-dependent LoS channels for UAVs in massive MIMO systems.

Findings

Effective pilot contamination mitigation demonstrated

Significant SINR improvements in uplink and downlink

Low-complexity distributed scheme validated through numerical results

Abstract

This letter studies the pilot contamination (PC) problem for massive multiple-input multiple-output (MIMO) networks with coexisting terrestrial users and unmanned aerial vehicles (UAVs). Due to the strong line-of-sight (LoS) air-to-ground channels between UAVs and base stations (BSs), UAVs usually cause a more severe PC issue as compared to the traditional terrestrial users. To mitigate the PC caused by UAVs, we propose a low-complexity distributed scheme by exploiting the full-dimensional beamforming of massive MIMO BSs and the angle-dependent LoS channels between them and high-altitude UAVs. Numerical results show the effectiveness of the proposed pilot decontamination scheme and the significant signal-to-interference-plus-noise ratio (SINR) gains in both the uplink and downlink after pilot decontamination.