UNITY-6G partners have co-authored a paper titled “XR Streaming Performance with Wi-Fi 7 Multi-Link Operation,” recently published in the IEEE Open Journal of the Communications Society. The study explores how the latest advancements in Wi-Fi technology can meet the demanding requirements of Extended Reality (XR) applications, particularly Virtual Reality (VR).
Key highlights from the research
The paper investigates the performance of Wi-Fi 7’s Multi-Link Operation (MLO) in supporting real VR traffic traces. Key findings include:
- Enhanced robustness: MLO supports VR applications with lower bandwidth and lower Modulation and Coding Scheme (MCS) levels than Single Link Operation (SLO), maintaining performance across a wide range of propagation conditions.
- Reduced latency: By using multiple independent channel access instances, MLO lowers delays—critical for uplink traffic, which has stricter requirements.
- Higher user capacity: MLO enables up to 50% more users per network compared to SLO when using an equivalent number of links.
- Optimal configuration matters: Properly configuring the number of links and channel bandwidth is key. While spreading bandwidth over multiple links improves capacity for higher user counts, having excess links does not necessarily improve performance for smaller groups of users.
- OBSS scenarios: In networks with overlapping traffic (Overlapping Basic Service Sets, OBSS), MLO outperforms SLO by opportunistically using available links and applying intelligent channel allocation to mitigate worst-case latency—addressing the so-called ‘MLO Performance Anomaly’.
The study demonstrates that Wi-Fi 7 MLO is a promising solution to meet the stringent throughput and latency demands of XR applications, paving the way for more immersive, responsive VR experiences.
Abstract—Extended Reality (XR) has stringent throughput and delay requirements that are hard to meet with current wireless technologies. Missing these requirements can lead to worsened picture quality, perceived lag between user input and corresponding output, and even dizziness for the end user. In this paper, we study the capability of Wi-Fi 7, and its novel support for Multi-Link Operation (MLO), to cope with these tight requirements. Our study is based on simulation results extracted from an MLO-compliant simulator that realistically reproduces VR traffic. Results show that MLO can sustain VR applications. By jointly using multiple links with independent channel access procedures, MLO can reduce the overall delay, which is especially useful in the uplink, as it has more stringent requirements than the downlink, and is instrumental in delivering the expected performance. We show that using MLO can support more users per Access Point (AP) than an equivalent number of links using Single Link Operation (SLO). We also show that, while maintaining the same overall bandwidth, a higher number of MLO links with narrower channels leads to lower delays than a lower number of links with wider channels. We also study the impact of Overlapping Basic Service Sets (OBSS) on performance of XR applications, showing how SLO struggles to maintain a low delay when OBSS activity increases, and how MLO can cope with this interference by using MLO-aware channel assignment strategies. Finally, we consider random positioning for the users, showcasing that MLO can support 5× more users than SLO.
Index Terms: Multi-Link Operation, XR streaming, IEEE 802.11be, Wi-Fi 7
Read the full paper to explore the detailed results and technical insights.
