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IEEE 802.11be Extremely High Throughput: The Next Generation of Wi-Fi Technology Beyond 802.11ax
David López-Pérez, Adrian Garcia-Rodriguez, Lorenzo Galati-Giordano, Mika Kasslin, Klaus Doppler
TL;DR
Growing demand for high-throughput and low-latency wireless services motivates Wi-Fi beyond 802.11ax. The article surveys 802.11be objectives, candidate features, coexistence, and system-level simulations, finding substantial throughput gains over 802.11ax in an enterprise scenario. It also notes that reaching the theoretical gain requires further coordination and coexistence study.
Problem
Growing video and application demands require wireless systems with higher throughput and lower latency than Wi-Fi 6 can provide.
Method
The article surveys 802.11be objectives, candidate features, coexistence issues, and system-level simulation results.
Results
802.11be provides median throughput gains of 3.2× downlink and 2.7× uplink, plus 5%-tile gains of 4.6× downlink and 2.2× uplink, relative to 802.11ax.
Takeaways & Limitations
The results indicate that larger transmission bandwidths and enhanced spatial multiplexing can provide substantial 802.11be throughput gains over 802.11ax.
Takeaways & Limitations
Further studies are needed to assess 802.11be gains with coordinated AP techniques and coexisting legacy 802.11 devices using contention-based access.
Abstract
from arXiv · showhide
Wi-Fi technology is continuously innovating to cater to the growing customer demands, driven by the digitalisation of everything, both in the home as well as the enterprise and hotspot spaces. In this article, we introduce to the wireless community the next generation Wi-Fi$-$based on IEEE 802.11be Extremely High Throughput (EHT)$-$, present the main objectives and timelines of this new 802.11be amendment, thoroughly describe its main candidate features and enhancements, and cover the important issue of coexistence with other wireless technologies. We also provide simulation results to assess the potential throughput gains brought by 802.11be with respect to 802.11ax.
I. INTRODUCTION
Rising demands for high-throughput, low-latency, and reliable wireless services are motivating Wi-Fi beyond 802.11ax. The article introduces 802.11be, its candidate technologies, coexistence issues, and simulated throughput gains.
- I. INTRODUCTION: Video and emerging applications are increasing wireless throughput and latency demands in homes, enterprises, and hotspots.4K/8K video may require tens of Gbps, while applications such as augmented reality, virtual reality, gaming, remote office, and cloud computing require stringent performance.
- I. INTRODUCTION: Remote office and cloud applications may require sub-5 ms latency and 99.99% deadline-constrained packet delivery reliability.
- I. INTRODUCTION: The IEEE 802.11 working group initiated new work across 1–7.125 GHz through a topic interest group, study group, and task group formed between May 2018 and May 2019.
- I. INTRODUCTION: The article surveys 802.11be objectives and timelines, candidate features, coexistence, and system-level simulation results.It is intended as an accessible guide for researchers and the broader Wi-Fi community.
II. OBJECTIVES AND TIMELINE
802.11be targets a major throughput increase while preserving coexistence with legacy Wi-Fi and shortening the amendment timeline. It also includes an intended mode for improved worst-case latency and jitter, although specific latency and reliability objectives had not yet been defined.
- II. OBJECTIVES AND TIMELINE: 802.11be targets at least 30 Gbps at the MAC data service access point, or 4× 802.11ax, across 1–7.125 GHz.
- II. OBJECTIVES AND TIMELINE: 802.11be must ensure backward compatibility and coexistence with legacy 802.11 devices in the 2.4, 5, and 6 GHz unlicensed bands.
- II. OBJECTIVES AND TIMELINE: At least one operating mode is intended to improve worst-case latency and jitter.The task group had not defined specific latency or reliability objectives at the time described.
- II. OBJECTIVES AND TIMELINE: The amendment is expected to span 5 years and deliver massive enhancements across many Wi-Fi use cases.
- II. OBJECTIVES AND TIMELINE: The approved development timeline is at least 6 months faster than 802.11ax.
III. CANDIDATE TECHNICAL FEATURES
802.11be considers a broad set of candidate technical features proposed by industrial and academic experts. The article focuses on the features attracting the most attention.
- III. CANDIDATE TECHNICAL FEATURES: Numerous industrial and academic experts have proposed candidate technical features for 802.11be.
A. 320 MHz bandwidth and more efficient utilisation of noncontiguous spectrum
802.11be seeks higher throughput through 6 GHz spectrum, wider channels, multi-band operation, full duplex, and multi-access point coordination. These approaches offer throughput, latency, coverage, and spatial-reuse benefits while introducing coexistence and coordination considerations.
- A. 320 MHz bandwidth and more efficient utilisation of noncontiguous spectrum: Up to 1.2 GHz of potentially accessible unlicensed spectrum between 5.925 and 7.125 GHz could more than double the 5 GHz band’s available bandwidth.
- A. 320 MHz bandwidth and more efficient utilisation of noncontiguous spectrum: 802.11be considers mandatory 160 MHz and optional 320 MHz communication bandwidth per AP in 6 GHz.A minimum 40 or 80 MHz channel size is also considered for 6 GHz, compared with 20 MHz in the 2.4 and 5 GHz bands.
- B. Multi-band/multi-channel aggregation and operation: Multi-band/multi-channel full duplex could reduce latency and increase throughput through asynchronous simultaneous uplink and downlink in separate bands or channels.A minimum separation between downlink and uplink channels may be needed to prevent mutual interference.
- B. Multi-band/multi-channel aggregation and operation: 802.11be considers separating data and management planes to reduce feedback delays and overheads that can impair scheduling and throughput.
C. 16 spatial streams and multiple-input multiple-output (MIMO) protocol enhancements
802.11be considers increasing AP spatial multiplexing to up to sixteen streams, potentially doubling spectral efficiency relative to 802.11ax. These gains may be constrained by channel-sounding overhead and hardware calibration requirements.
- 16 spatial streams: 16 spatial streams could double 802.11be spectral efficiency relative to 802.11ax by exploiting fiber backhaul and indoor rich scattering.
- MIMO protocol enhancements: Channel-sounding overhead may hinder spatial-multiplexing gains because doubling streams with 802.11ax’s explicit CSI procedure may not scale.Channel sounding is needed to acquire accurate channel state information.
- MIMO protocol enhancements: 802.11be is considering implicit sounding based on STA-transmitted pilots and uplink/downlink channel reciprocity.Implicit sounding would likely require AP calibration to prevent hardware mismatches from breaking reciprocity.
D. Multi-access point coordination
802.11be considers coordinated multi-AP techniques that share time, frequency, and spatial resources to improve utilization, reduce collisions, and strengthen spatial reuse and coverage. Coordination ranges from synchronized orthogonal resource assignment to tightly collaborative distributed MIMO.
- Coordination overview: Multi-AP collaboration can improve utilization of limited time, frequency, and spatial resources, with alternatives ordered by increasing coordination complexity.
- Coordinated OFDMA: Coordinated OFDMA synchronizes collaborative AP transmissions over orthogonal time/frequency resources, reducing collision probability versus independent contention-based access.It is attractive for short packets because it enables efficient band sharing without repeated contention processes.
- Coordinated beamforming: Coordinated null steering places spatial radiation nulls toward non-associated devices, enabling simultaneous same-resource transmissions and boosting spatial reuse.
- Distributed MIMO: Distributed MIMO jointly transmits or receives through non-collocated APs and multiple STAs using the same time/frequency resources.
- Distributed MIMO: D-MIMO can extend coverage and improve spatial multiplexing by turning neighboring APs from interferers into servers through tight inter-AP collaboration.
E. Enhanced link adaptation and retransmission protocol
802.11be considers enhanced retransmission mechanisms to meet higher reliability and lower latency requirements, but HARQ’s throughput benefits and implementation costs remain uncertain in realistic Wi-Fi conditions.
- Retransmission protocol: Current Wi-Fi ARQ retransmits unsuccessfully decoded MPDUs but discards failed versions, preventing soft-combining.
- Enhanced retransmission: HARQ could provide gains in ideal additive white Gaussian noise channels, but stakeholders question its throughput benefits under bursty collision interference.
- Enhanced retransmission: HARQ requires additional computation and memory to soft-combine and store past transmissions, so further studies must assess Wi-Fi performance and complexity.
IV. COEXISTENCE IN THE 6 GHZ BAND
802.11be aims to use potentially available 6 GHz spectrum, but access requires coexistence with incumbent services and newcomer technologies. Regulatory coexistence requirements and technical mechanisms remained under discussion, with listen-before-talk likely governing newcomer interactions.
- 6 GHz spectrum: 802.11be seeks to use up to 1.2 GHz of 6 GHz spectrum, which must be shared with other technologies.
- Coexisting technologies: The 6 GHz band may contain incumbent fixed and mobile services alongside newcomer IEEE and 3GPP technologies such as 802.11be and NR-U.
- Regulatory coexistence: Regulators are likely to define coexistence requirements preventing newcomers from generating harmful interference to incumbent 6 GHz services.
- Regulatory coexistence: The entire 6 GHz band may not be dedicated to unlicensed use, and allocation decisions may vary by country.
- Coexistence mechanisms: Coexistence mechanisms for incumbents remained under regulatory discussion, including geolocation and database methods with interference detection and mitigation.
- Newcomer coexistence: Listen-before-talk is likely to govern coexistence among newcomers such as 802.11ax/be and NR-U, potentially without 5 GHz-style incumbent energy-detection advantages.
V. 802.11BE PERFORMANCE EVALUATION
The paper evaluates 802.11be throughput gains over 802.11ax through detailed system-level simulations in a realistic enterprise scenario.
- V. 802.11BE PERFORMANCE EVALUATION: The simulations model a 40 m ×40 m, 3 m-high company building upgrading 16 grid-deployed 802.11ax APs using four reused channels.The scenario replaces the existing APs with newer APs implementing a key subset of 802.11be features.
1) More bandwidth:
The evaluation compares aggregate per-AP downlink and uplink throughput distributions for 802.11ax and 802.11be, under stated system assumptions and averaging procedures. 802.11be achieves substantial gains, although realistic conditions limit them below the approximately 4× theoretical maximum.
- 1) More bandwidth:: The evaluation assumes 802.11be APs use 160 MHz transmissions in 6 GHz, while 802.11ax APs use 80 MHz transmissions.The comparison also assumes no CSI acquisition errors in either system.
- 1) More bandwidth:: Fig. 4 presents CDFs of aggregate downlink and uplink throughput per AP at the MAC data service access point for both deployments.Results are averaged over 100 random simulation drops, each representing 10 s of operation.
- 1) More bandwidth:: 802.11be improves median throughput by 3.2× downlink and 2.7× uplink, while 5%-tile throughput improves by 4.6× downlink and 2.2× uplink.These gains are attributed to larger transmission bandwidths and enhanced spatial multiplexing capabilities.
- 1) More bandwidth:: The gains remain below the approximately 4× theoretical maximum because cell-edge SINRs can decline, 16-STA multiplexing is not always achieved, and spatial correlation can increase.Larger bandwidth raises noise power, while multiplexing more STAs can degrade their per-STA SINRs.
- 1) More bandwidth:: The approximately 4× theoretical gain requires doubling bandwidth and spatial streams, but some AP coordination would be needed to reach it.The paper calls for further study of coordination and coexistence with legacy devices using contention-based access.
VI. CONCLUSION
The paper surveys the initial creation and standardisation of 802.11be beyond 802.11ax, covering objectives, timelines, stakeholder views, candidate features, coexistence, and enterprise simulation results.
- VI. CONCLUSION: The article presents 802.11be objectives and expected timelines, stakeholder viewpoints, candidate features with their benefits and challenges, and system-level results in a typical enterprise scenario.The authors describe the standardisation process as having just started, with its future still open.