A Survey and Quantitative Analysis of Network Architectures for Future 6G Services in Rural and Underserved Areas
Bridging the rural digital divide remains a persistent global challenge despite the widespread deployment of 4G and 5G cellular networks. This paper presents a comprehensive survey and quantitative analysis of network architectures for enabling future sixth-generation (6G) services in rural and underserved regions. Drawing on a structured review of peer-reviewed studies, 3GPP and ITU-R standards, O-RAN Alliance specifications, and documented field deployments, we classify and evaluate four architectural categories: terrestrial networks (TNs), non-terrestrial networks (NTNs), hybrid TN–NTN systems, and Open Radio Access Network (O-RAN)-based deployments. Each architecture is assessed against International Mobile Telecommunications for 2030 (IMT-2030) performance targets for throughput, end-to-end round-trip latency, energy efficiency (expressed as energy consumed per bit), coverage, and reliability. Unlike prior surveys that address individual components in isolation, such as satellite backhaul, microwave transport, or O-RAN frameworks, this paper provides a unified, deployment-driven, and quantitatively grounded treatment of all four architectural classes under rural 6G constraints. The survey analyzes key enabling technologies including Integrated Access and Backhaul (IAB), High-Altitude Platform Stations (HAPSs), Low-Earth Orbit (LEO) satellite systems, Reconfigurable Intelligent Surfaces (RIS), and AI-native orchestration frameworks. Analytical models are presented for RIS-assisted link enhancement and AI-native RAN Intelligent Controller (RIC) control utility. A quantitative, normalized key performance indicator (KPI) comparison across cost efficiency, spectral utilization, power consumption, and deployment scalability is grounded in a transparent scoring methodology, extended with a multi-criteria (AHP) architecture ranking, a weight-sensitivity analysis, and a parametric techno-economic cost-per-user comparison, and supported by an extensive review of technical, industrial, and policy literature. Beyond current deployments, this work identifies emerging technologies, including direct-to-device non-terrestrial access, programmable radio environments, and intelligent RAN control, that are expected to play a central role in extending sustainable rural 6G connectivity. A practical deployment decision framework and scenario-driven architectural guidance are provided for researchers, network operators, and policymakers pursuing inclusive, future-ready rural connectivity.