Dense Wi-Fi Networks Optimization (SR, D-MIMO, PON)

Dense Wi-Fi networks, characterized by a high concentration of access points and user devices within a limited area, pose significant challenges for reliable and efficient wireless communication. In such environments, performance is often constrained not by peak physical-layer data rates but by increased co-channel and adjacent-channel interference, intensified contention for shared spectrum, and frequent collisions caused by overlapping transmissions. Recent and upcoming IEEE 802.11 amendments introduce mechanisms such as spatial reuse (SR), orthogonal frequency division multiple access (OFDMA), and coordinated access to improve efficiency in dense scenarios.

OFDMA is a key multi-user transmission mechanism introduced in IEEE 802.11ax (Wi-Fi 6). By partitioning the channel into smaller frequency-time resource units (RUs), OFDMA enables simultaneous transmissions to or from multiple users. This approach reduces contention overhead and improves spectrum efficiency, particularly for uplink traffic and for downlink scenarios with many active users carrying small or sporadic packets. It has been shown that OFDMA can achieve a significant increase in Wi-Fi performance compared to legacy operation. RU allocation algorithms demonstrate OFDMA advantages in scenarios with multiple access points. The use of OFDMA also reduces network delays, which is especially important for delay-sensitive applications such as virtual reality (VR) or extended reality (XR).

Coordinated OFDMA (Co-OFDMA) further generalizes multi-user scheduling across multiple APs by jointly managing RU allocations so that simultaneous transmissions occupy non-overlapping RUs, enabling concurrent downlink or uplink operation across BSSs. Coordinated usage of OFDMA and direct links improves the reliability of VR traffic transmission without degrading the quality of service of background traffic. Resource allocation algorithms for general Co-OFDMA systems with multiple BSS and users have shown that the number of satisfied VR users can increase to 90% compared to legacy Wi-Fi operation.

Statistics-based rate control algorithms that consider variations in interference due to SR substantially improve throughput and latency in dense scenarios. Coordinated interference management by jointly optimizing transmit power and channel time scheduling can boost overall throughput while preserving fairness among users. Centralized, cloud-based approaches using parameter tuning, such as transmit powers and sensitivity thresholds, achieve higher energy efficiency. Algorithms combining Co-OFDMA and SR features provide stable gains over separate usage of Co-OFDMA or SR.

List of relevant papers:


      2023
    1. Evgeny Khorov, Vyacheslav Loginov, Mary Mirzoian. M-TDLS: Enhancement of VR Quality of Service Using Coordinated OFDMA and Direct Links. //2023 IEEE Conference on Standards for Communications and Networking (CSCN). – IEEE, 2023. – С. 408-412. https://doi.org/10.1109/CSCN60443.2023.10453194.

      2. 2021
    2. Dmitry Bankov, Evgeny Khorov, Sergei Tutelian, Dmitri Shmelkin. IEEE 802.11ax OFDMA Resource Allocation with Frequency-Selective Fading. //Sensors. – 2021. – Т. 21. – №. 18. – С. 6099. https://doi.org/10.3390/s21186099.

      3. 2020
    3. Evgeny Khorov, Alexander Krotov, Ian F. Akyildiz, Anton Kiryanov. Enhancing the Energy Efficiency of Dense Wi-Fi Networks Using Cloud Technologies. Automation and Remote Control. 2020. Vol. 81, No. 1, pp. 82-95.

      4. 2018
    4. Evgeny Khorov, Aleksei Kureev, Andrey Lyakhov, Ilya Levitsky. Testbed to Study the Capture Effect: Can We Rely on This Effect in Modern Wi-Fi Networks. In proc. of IEEE International Black Sea Conference on Communications and Networking, Batumi, Georgia, 2018 .
    5. Evgeny Khorov, Alexander Krotov, Anton Kiryanov. Joint Power Control and Time Division to Improve Spectral Efficiency in Dense Wi-Fi Networks. In proc. of IEEE International Black Sea Conference on Communications and Networking, Batumi, Georgia, 2018 .
    6. Dmitry Bankov, Evgeny Khorov, Andrey Lyakhov, Andre Didenko. OFDMA Uplink Scheduling in IEEE 802.11ax Networks. In Proc. of IEEE International Conference on Communications (ICC), Kansas City, USA, 2018 .

      7. 2017
    7. Dmitry Bankov, Evgeny Khorov, Vyacheslav Loginov, Andrey Lyakhov, Andre Didenko. IEEE 802.11ax Uplink Scheduler to Minimize Delay: a Classic Problem with New Constraints. In Proc. of IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC\\\\\\\'17), Montreal, Canada, 2017.