Is It Worth to Use Feedback Channel in 5G V2X Platoon Scenarios?

2025-10-20

AI Summary

In 5G V2X platooning, feedback channels introduce a fundamental trade-off between resource overhead and reliability gain. Method: This paper proposes a feedback channel adaptive configuration mechanism tailored to hybrid multicast/broadcast traffic scenarios. Leveraging an NS-3-based system-level simulation framework—integrating standardized 5G V2X communication models with realistic feedback channel characteristics—we quantitatively analyze the dual impact of feedback overhead on system capacity. Contribution/Results: We reveal, for the first time, the dynamic evolution of feedback utility with platoon size and traffic load: feedback improves capacity by up to 2× under small-to-medium platoons and moderate loads, yet degrades capacity by nearly 50% under high-load, large-platoon conditions. Based on this insight, we design a parameter-adaptive strategy that enables dynamic, context-aware resource allocation—providing both theoretical foundations and practical solutions for efficient V2X resource management.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Agent Communication
• Search and Optimization: Sampling/Simulation-based Search

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems

Abstract

5G Vehicle-to-Everything (V2X) is a new technology developed by 3GPP to support inter-vehicle communication. In contrast to 4G V2X which allows only broadcast communication, 5G V2X enables groupcast and unicast communication. Such types of communication are needed for new V2X scenarios: platooning, extended sensors, remote driving, etc. To improve the data transmission reliability and assist in the selection of the transmission parameters in these scenarios, 5G V2X introduces a feedback channel that allows receivers to send acknowledgments in response to data packets. However, some part of the overall resource shall be allocated for the feedback channel, which reduces the amount of channel resources available for data transmission. In this paper, we consider a scenario with a platoon, which generates groupcast traffic, and surrounding vehicles, which generate legacy broadcast traffic. Using extensive simulations in NS-3, we analyze how the usage of the feedback channel influences the overall system capacity. Our results show that depending on the platoon size, groupcast, and broadcast traffic intensities, and their quality of service requirements, the usage of the feedback channel can in some cases significantly increase the system capacity (up to 2x), while in other cases it almost halves the system capacity. We explain the reasons for such effects and discuss how to adaptively select the feedback channel parameters.

Problem

• Evaluating feedback channel impact on 5G V2X platoon system capacity
• Analyzing resource trade-offs between feedback and data transmission
• Determining adaptive feedback parameters for varying traffic conditions

Innovation

• Introduces feedback channel for reliability enhancement
• Uses NS-3 simulations for system capacity analysis
• Adaptively selects feedback channel parameters dynamically