Measurement-based Massive-MIMO Channel Characterization for Outdoor LoS Scenarios

Massive multiple-input multiple-output (MIMO) transmission is one of the key technologies utilized in the fifth generation (5G) wireless communication system. For the algorithm design and the performance evaluation of massive-MIMO, channel characterization based on real measurements is necessary. In this paper, we introduced a measurement campaign conducted in a Line-of-Sight (LoS) scenario of a suburban outdoor environment. The channel sounder is equipped with a 64-element transmitter array and a 64-element receiver array. Multiple aspects of massive-MIMO channel characteristics are considered, including the power delay profile, the K-factor and the delay-spread. We found that for the outdoor LoS scenario considered, the polarization plays an important role generating orthogonal channels observed through large-scale antenna arrays.

I. Introduction

Very-large MIMO systems, also known as massive MIMO or large-scale antenna systems, is a new research field in wireless communications [1]. Massive MIMO transmission has been considered as a key technology for the air interface between base stations (BSs) and multiple user equipments (UEs) in the 5G wireless communication systems and networks [2], [3]. The more antennas the transmitter or receiver is equipped with, the more degrees of freedom that the propagation channel can provide theoretically, and the better performance in terms of data rate or link reliability [4].