Performance of Cell-Free Massive MIMO in Realistic Urban Propagation Environments

TL;DR

This paper compares cell-free massive MIMO performance in idealized versus realistic urban environments, revealing that real urban propagation significantly reduces throughput and uniformity, challenging its practical deployment benefits.

Contribution

It provides the first comparative analysis of CF-mMIMO performance using raytracing-based urban propagation models versus traditional log-distance models.

Findings

Raytracing model shows lower throughput than log-distance model.

CF-mMIMO's uniform performance is compromised in realistic urban environments.

Results question the practicality of CF-mMIMO in real urban deployments.

Abstract

While UE-centric cell-free massive MIMO (CF-mMIMO) provides high and uniform throughput performance under the assumption of a uniform propagation environment modeled by the log-distance path loss channel model, the performance under a realistic urban propagation environment is not yet fully addressed. In this paper we conduct the first comparative performance study of CF-mMIMO under both the widely assumed log-distance channel model and the realistic urban propagation environment obtained via raytracing using real 3D city layouts and practical AP locations. Our results show that with the raytracing channel model, CF-mMIMO cannot achieve as high and uniform throughput performance as observed with the log-distance channel model, putting into question the attractiveness in practice of CF-mMIMO for real urban deployments.