Ten Years of Research Advances in Full-Duplex Massive MIMO

TL;DR

This paper reviews a decade of research on full-duplex massive MIMO systems, emphasizing cell-free architectures and network-assisted approaches for next-generation wireless networks.

Contribution

It provides a comprehensive overview of the evolution, current state, and future directions of full-duplex massive MIMO, especially focusing on cell-free and network-assisted architectures.

Findings

Cell-free massive MIMO offers scalable distributed system benefits.

Network-assisted IBFD CF-mMIMO enables energy-efficient asymmetric communication.

Emerging applications include wireless power transfer and integrated sensing.

Abstract

We present an overview of ongoing research endeavors focused on in-band full-duplex (IBFD) massive multiple-input multiple-output (MIMO) systems and their applications. In response to the unprecedented demands for mobile traffic in concurrent and upcoming wireless networks, a paradigm shift from conventional cellular networks to distributed communication systems becomes imperative. Cell-free massive MIMO (CF-mMIMO) emerges as a practical and scalable implementation of distributed/network MIMO systems, serving as a crucial physical layer technology for the advancement of next-generation wireless networks. This architecture inherits benefits from co-located massive MIMO and distributed systems and provides the flexibility for integration with the IBFD technology. We delineate the evolutionary trajectory of cellular networks, transitioning from conventional half-duplex multi-user MIMO networks to IBFD CF-mMIMO. The discussion extends further to the emerging paradigm of network-assisted IBFD CF-mMIMO (NAFD CF-mMIMO), serving as an energy-efficient prototype for asymmetric uplink and downlink communication services. This novel approach finds applications in dual-functionality scenarios, including simultaneous wireless power and information transmission, wireless surveillance, and integrated sensing and communications. We highlight various current use case applications, discuss open challenges, and outline future research directions aimed at fully realizing the potential of NAFD CF-mMIMO systems to meet the evolving demands of future wireless networks.