A State-of-the-art Survey on Full-duplex Network Design

TL;DR

This survey addresses the network-level challenges of deploying full-duplex (FD) communications, focusing on inter-node interference, self-interference cancellation, and cross-layer protocol adaptations across PHY, MAC, and RRC. It consolidates state-of-the-art FD MAC designs for WLAN, FD cellular user scheduling, and cross-link interference management, and evaluates these approaches using 3D ray-tracing-based system-level simulations. Key contributions include a cross-layer FD design framework, CLI measurement and mitigation strategies, and a comparison of MAC/scheduling paradigms with a network-wide perspective. The work highlights the necessity of centralized coordination, interference-aware scheduling, and realistic evaluation to realize FD gains in 5G/6G networks. The findings suggest that SI can be largely mitigated with SIC, but ICI and CLI, if not properly managed via scheduling and beamforming, can bottleneck FD performance in dense deployments.

Abstract

Full-duplex (FD) technology is gaining popularity for integration into a wide range of wireless networks due to its demonstrated potential in recent studies. In contrast to half-duplex (HD) technology, the implementation of FD in networks necessitates considering inter-node interference (INI) from various network perspectives. When deploying FD technology in networks, several critical factors must be taken into account. These include self-interference (SI) and the requisite SI cancellation (SIC) processes, as well as the selection of multiple user equipment (UE) per time slot. Additionally, inter-node interference (INI), including cross-link interference (CLI) and inter-cell interference (ICI), become crucial issues during concurrent uplink (UL) and downlink (DL) transmission and reception, similar to SI. Since most INI is challenging to eliminate, a comprehensive investigation that covers radio resource control (RRC), medium access control (MAC), and the physical layer (PHY) is essential in the context of FD network design, rather than focusing on individual network layers and types. This paper covers state-of-the-art studies, including protocols and documents from 3GPP for FD, MAC protocol, user scheduling, and CLI handling. The methods are also compared through a network-level system simulation based on 3D ray-tracing.

Figures (10)

• Figure 1: Challenges for full-duplex network design.
• Figure 2: Full-duplex network topology and description of duplex mode.
• Figure 3: Illustration of inter-node interference and hidden node problem in full-duplex communications.
• Figure 4: An illustration depicting the fairness issue between FD and HD nodes arising from the EIFS waiting time. In this scenario, an AP and FD node A are engaged in FD transmission, with FD node B located near node A and HD node C in the vicinity of the AP.
• Figure 5: Scheduling issue for FD network design.