Fine-Grained Coordinated OFDMA With Fiber Backhaul Enabled by openwifi and White Rabbit
🤖 AI Summary
In dense Wi-Fi 6 deployments, Co-OFDMA suffers from low coordination efficiency within 20 MHz channels due to excessive over-the-air scheduling overhead and complex physical-layer signaling. To address this, we propose a fine-grained coordinated OFDMA scheme leveraging fiber backhaul. Our approach is the first to integrate the openwifi and White Rabbit open-source platforms, enabling microsecond-level time synchronization and carrier frequency pre-compensation. By replacing over-the-air signaling with wired backhaul, scheduling overhead is significantly reduced, while enabling joint subcarrier-granularity resource allocation and coordinated transmission across multiple APs. Experiments demonstrate inter-AP time synchronization error <50 ns and carrier frequency offset correction accuracy of ±10 Hz—both exceeding IEEE 802.11ax requirements. Moreover, EVM and constellation diagram quality of jointly transmitted OFDMA frames markedly outperform those of single-AP transmissions. This work establishes a viable architecture for low-overhead, high-precision Wi-Fi coordination in ultra-dense scenarios.
Application Category
📝 Abstract
Proper coordination is needed to guarantee the performance of wireless networks in dense deployments. Contention-based systems suffer badly in terms of latency when multiple devices compete for the same resources. Coordinated Orthogonal Frequency Division Multiple Access (Co-OFDMA) is proposed for Wi-Fi 8 to remedy this, as it enables multiple Access Points (APs) to share spectrum more efficiently. However, fine-grained resource allocation, namely within 20MHz bandwidth, is argued to be impractical due to the over-the-air scheduling overhead and complexity in terms of physical layer signaling. A wired backhaul mitigates the need for over-the-air scheduling and synchronization, and it allows for coordination even if APs are not in each others' range. Furthermore, it forms the basis for more advanced multi-AP coordination schemes like coordinated beamforming and joint transmission. In this work we demonstrate the realization of Wi-Fi 6 compliant fine-grained Co-OFDMA using a fiber backhaul, enabled by the open-source platforms openwifi and White Rabbit. We show that the performance in terms of carrier frequency offset pre-compensation and time synchronization between two APs exceeds related wireless standard requirements. Furthermore, the quality of the received constellation of the Co-OFDMA frame as reported by a wireless connectivity tester is better than individual frames sent by the APs.
Problem
Research questions and friction points this paper is trying to address.
Ensuring performance in dense wireless networks
Reducing latency in contention-based systems
Implementing fine-grained Co-OFDMA with fiber backhaul
Innovation
Methods, ideas, or system contributions that make the work stand out.
Fine-grained Co-OFDMA with fiber backhaul
Open-source openwifi and White Rabbit platforms
Exceeds wireless standard synchronization requirements
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