Design and Evaluation of IEEE 802.11ax Uplink Orthogonal Frequency Division Multiple Random Access in ns-3

2025-06-27

AI Summary

To address the high overhead and low reliability of the Enhanced Distributed Channel Access (EDCA) mechanism in dense Wi-Fi networks—caused by contention and collisions—this paper designs and implements the first fully IEEE 802.11ax-compliant, open-source, and reproducible Uplink OFDMA Random Access (UORA) mechanism, integrated into the ns-3.38 network simulator. Unlike prior implementations, our design overcomes critical limitations—including lack of Trigger Frame (TF) reuse across scheduling and data transmission, and absence of standardized UORA configuration signaling—enabling fine-grained resource reservation and hybrid access (scheduled + random). Experimental results demonstrate that the proposed UORA significantly reduces access latency and collision probability while improving multi-user concurrency and system scalability. This work establishes an open, standardized, and high-fidelity simulation foundation for research on resource allocation in Wi-Fi 6/7 networks.

Technology Category

• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Search and Optimization: Sampling/Simulation-based Search
• Multiagent Systems: Mechanism Design

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• Web Mining and Content Analysis: Web data generation and simulation
• Responsible Web: Data and user privacy-enhancing technologies for the Web

Abstract

Wi-Fi networks have long relied on the Enhanced Distributed Channel Access (EDCA) mechanism, allowing stations to compete for transmission opportunities. However, as networks become denser and emerging applications demand lower latency and higher reliability, the limitations of EDCA such as overhead due to contention and collisions have become more pronounced. To address these challenges, Orthogonal Frequency Division Multiple Access (OFDMA) has been introduced in Wi-Fi, enabling more efficient channel utilization through scheduled resource allocation. Furthermore, Wi-Fi 6 defines Uplink Orthogonal Frequency Division Multiple Random Access (UORA), a hybrid mechanism that combines both scheduled and random access, balancing efficiency and responsiveness in resource allocation. Despite significant research on UORA, most studies rely on custom simulators that are not publicly available, limiting reproducibility and preventing validation of the presented results. The only known open-source UORA implementation in the ns-3 simulator exhibits key limitations, such as usage of the same trigger frame (TF) to schedule resources for buffer status reports and data transmissions, and lack of signaling for UORA configuration. In this paper, we present a fully standard-compliant and open source UORA implementation that is compatible with ns-3 version 3.38, addressing these limitations to improve resource allocation efficiency and adaptability. This implementation enables more accurate and flexible evaluation of UORA, fostering future research on Wi-Fi resource allocation strategies.

Problem

• Improves IEEE 802.11ax UORA efficiency in dense Wi-Fi networks
• Addresses limitations of open-source UORA in ns-3 simulator
• Enables accurate evaluation of hybrid scheduled-random access

Innovation

• Standard-compliant UORA implementation in ns-3
• Hybrid OFDMA and random access mechanism
• Improved resource allocation efficiency and adaptability