Cell-free versus Conventional Massive MIMO : An Analysis of Channel Capacity based on Channel Measurement in the FR3 Band

TL;DR

This paper presents the first extensive channel measurements for cell-free massive MIMO in the FR3 band, comparing its capacity to conventional MIMO and analyzing the impact of array configurations and propagation conditions.

Contribution

It provides the first measurement-based comparison of CF-mMIMO and conventional MIMO in the FR3 band, offering insights into capacity gains and optimal array configurations.

Findings

CF-mMIMO shows 14.02% capacity gain under LOS conditions.

CF-mMIMO shows 24.61% capacity gain under NLOS conditions.

64-element array configuration offers the greatest capacity advantage.

Abstract

Cell-free massive MIMO (CF-mMIMO) has emerged as a promising technology for next generation wireless systems, combining the benefits of distributed antenna systems (DAS) and traditional MIMO technology. In this work, we present the first extensive channel measurements for CF-mMIMO in the mid-band (FR3, 6-24 GHz), using a virtual widely distributed antenna array comprising 512 elements in the urban Macrocell (UMa) environment. Based on the measurement data, this paper compares the channel capacity of CF-mMIMO and Conventional mMIMO under both line-of-sight (LOS) and non-line-of-sight (NLOS) conditions across a range of signal-to-noise ratios (SNRs). We then analyze how channel capacity varies with Rx positions from the perspectives of the full array and of individual subarrays. Finally, we conclude that the 64-element array configuration yields the greatest advantage in channel capacity for CF-mMIMO in the measurement environment considered, with gains of 14.02\% under LOS and 24.61\% under NLOS conditions. This in-depth analysis of channel capacity in the FR3 band provides critical insights for optimizing CF-mMIMO systems in next generation wireless networks.