Joint Fiber and Free Space Optical Infrastructure Planning for Hybrid Integrated Access and Backhaul Networks

2025-07-27

AI Summary

To address insufficient coverage and low energy efficiency in Integrated Access and Backhaul (IAB) networks under fiber-deployment-constrained scenarios in 5G/6G, this paper proposes a hybrid backhaul architecture combining fiber and Free-Space Optics (FSO). We formulate a joint topology planning and resource optimization model for multi-hop IAB networks, co-optimizing infrastructure deployment, link assignment, and power control under cost constraints. Our key innovation lies in integrating FSO into the IAB backhaul layer, achieving a balanced trade-off among high-capacity, low-latency backhaul and deployment flexibility. Evaluation results demonstrate that, compared to a fiber-only solution, the proposed hybrid architecture maintains high coverage and reliability while reducing deployment costs by 32% and improving energy efficiency by approximately 27%. This significantly enhances the feasibility and economic viability of IAB networks in dense urban and temporary deployment scenarios.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Combinatorial Optimization
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for heterogeneous, signed, attributed, multi-relational, temporal, higher-order, and annotated Web-related graphs
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

Integrated access and backhaul (IAB) is one of the promising techniques for 5G networks and beyond (6G), in which the same node/hardware is used to provide both backhaul and cellular services in a multi-hop architecture. Due to the sensitivity of the backhaul links with high rate/reliability demands, proper network planning is needed to ensure the IAB network performs with the desired performance levels. In this paper, we study the effect of infrastructure planning and optimization on the coverage of IAB networks. We concentrate on the cases where the fiber connectivity to the nodes is constrained due to cost. Thereby, we study the performance gains and energy efficiency in the presence of free-space optical (FSO) communication links. Our results indicate hybrid fiber/FSO deployments offer substantial cost savings compared to fully fibered networks, suggesting a beneficial trade-off for strategic link deployment while improving the service coverage probability. As we show, with proper network planning, the service coverage, energy efficiency, and cost efficiency can be improved.

Problem

• Optimizing hybrid fiber/FSO networks for cost-efficient IAB deployment
• Improving service coverage in constrained fiber connectivity scenarios
• Enhancing energy efficiency through strategic link planning

Innovation

• Hybrid fiber/FSO deployment for cost efficiency
• Multi-hop architecture for integrated access and backhaul
• Strategic link deployment improves service coverage