Exploiting the Depth and Angular Domains for Massive Near-Field Spatial Multiplexing

TL;DR

This paper explores how extremely large aperture arrays in future 6G networks can leverage near-field effects, such as depth and angular domains, to significantly enhance data rates through advanced spatial multiplexing techniques.

Contribution

It introduces novel near-field multiplexing schemes exploiting depth and angular domains enabled by large aperture arrays in 6G communication systems.

Findings

Near-field effects improve channel matrix properties for multiplexing.

Depth-domain multiplexing allows multiple users to be served simultaneously.

Angular multiplexing enhances data streams to a single user.

Abstract

In this article, we present our vision for how extremely large aperture arrays (ELAAs), equipped with hundreds or thousands of antennas, can play a major role in future 6G networks by enabling a remarkable increase in data rates through spatial multiplexing of a massive number of data streams to both a single user and many simultaneous users. Specifically, with the quantum leap in the array aperture size, the users will be in the so-called radiative near-field region of the array, where previously negligible physical phenomena dominate the propagation conditions and give the channel matrices more favorable properties. This article presents the foundational properties of communication in the radiative near-field region and then exemplifies how these properties enable two unprecedented spatial multiplexing schemes: depth-domain multiplexing of multiple users and angular multiplexing of data streams to a single user. We also highlight research challenges and open problems that require further investigation.