Ubiquitous Cell-Free Massive MIMO Communications

Abstract

Since the first cellular networks were trialled in the 1970s, we have witnessed an incredible wireless revolution. From 1G to 4G, the massive traffic growth has been managed by a combination of wider bandwidths, refined radio interfaces, and network densification, namely increasing the number of antennas per site. Due its cost-efficiency, the latter has contributed the most. Massive MIMO (multiple-input multiple-output) is a key 5G technology that uses massive antenna arrays to provide a very high beamforming gain and spatially multiplexing of users, and hence, increases the spectral and energy efficiency. It constitutes a centralized solution to densify a network, and its performance is limited by the inter-cell interference inherent in its cell-centric design. Conversely, ubiquitous cell-free Massive MIMO refers to a distributed Massive MIMO system implementing coherent user-centric transmission to overcome the inter-cell interference limitation in cellular networks and provide additional macro-diversity. These features, combined with the system scalability inherent in the Massive MIMO design, distinguishes ubiquitous cell-free Massive MIMO from prior coordinated distributed wireless systems. In this article, we investigate the enormous potential of this promising technology while addressing practical deployment issues to deal with the increased back/front-hauling overhead deriving from the signal co-processing.

Published in EURASIP Journal on Wireless Communications and Networking on August 5, 2019

References in corpus (4)

• Scalability Aspects of Cell-Free Massive MIMO
• How Much Do Downlink Pilots Improve Cell-Free Massive MIMO?
• Linear Precoding and Equalization for Network MIMO with Partial Cooperation
• Achieving Large Multiplexing Gain in Distributed Antenna Systems via Cooperation with pCell Technology

Cited by in corpus (31)

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• Improving Sum-Rate of Cell-Free Massive MIMO with Expanded Compute-and-Forward
• Enabling Cell-Free Massive MIMO Systems with Wireless Millimeter Wave Fronthaul
• Enhanced Normalized Conjugate Beamforming for Cell-Free Massive MIMO
• Massive MIMO with Radio Stripes for Indoor Wireless Energy Transfer
• Generalized Coordinated Multipoint Framework for 5G and Beyond
• Centralized and Distributed Power Allocation for Max-Min Fairness in Cell-Free Massive MIMO
• Optimal Bilinear Equalizer for Cell-Free Massive MIMO Systems over Correlated Rician Channels
• Joint Optimization of Uplink Power and Computational Resources in Mobile Edge Computing-Enabled Cell-Free Massive MIMO
• User-centric Handover in mmWave Cell-Free Massive MIMO with User Mobility
• On the Ground and in the Sky: A Tutorial on Radio Localization in Ground-Air-Space Networks
• Activity Detection for Massive Connectivity in Cell-free Networks with Unknown Large-scale Fading, Channel Statistics, Noise Variance, and Activity Probability: A Bayesian Approach
• Co-Located vs Distributed vs Semi-Distributed MIMO: Measurement-Based Evaluation
• A Decentralized Pilot Assignment Algorithm for Scalable O-RAN Cell-Free Massive MIMO
• User Subgrouping and Power Control for Multicast Massive MIMO over Spatially Correlated Channels
• RadioWeaves for Extreme Spatial Multiplexing in Indoor Environments
• Cell-Free Massive MIMO with Multi-Antenna Users and Phase Misalignments: A Novel Partially Coherent Transmission Framework
• Spectral Efficiency Analysis of Cell-free Distributed Massive MIMO Systems with Imperfect Covariance Matrix
• Team Precoding Towards Scalable Cell-free Massive MIMO Networks
• Cell-free Massive MIMO with Sequential Fronthaul Architecture and Limited Memory Access Points
• Spectral-Efficiency of Cell-Free Massive MIMO with Multicarrier-Division Duplex
• A Low Complexity Space-Time Block Codes Detection for Cell-Free Massive MIMO Systems
• Coexistence of eMBB+ and mMTC+ in Uplink Cell-Free Massive MIMO Networks
• Self-Learning Detector for the Cell-Free Massive MIMO Uplink: The Line-of-Sight Case
• Distributed MIMO Precoding with Routing Constraints in Segmented Fronthaul
• Analysis of UAV Communications in Cell-Free Massive MIMO systems
• Towards Cell-Free Massive MIMO: A Measurement-Based Analysis