While customers rivet their eyes on Wi-Fi 6, in the bowels of the IEEE 802.11 Working Group that creates Wi-Fi standards, the next generation Wi-Fi is being developed. At the very first sight, the new IEEE 802.11be amendment to the Wi-Fi standard is nothing but scaled 11ax with doubled bandwidth and the increased number of spatial streams, which together provide data rates as high as 40 Gbps. A bit deeper dive into the 802.11 activities reveals that 11be will support real-time applications. In reality, 11be introduces many more revolutionary changes to Wi-Fi, which will form a basement for further Wi-Fi evolution. Although by now (May 2020), the development process is at the very early phase without any draft specification, the analysis of the discussion in the 802.11 Working Group gives insights into the main innovations of 11be. In addition to the ones above, they include native multi-link operation, channel sounding optimization that opens the door for massive MIMO, advanced PHY and MAC techniques, the cooperation of various access points. The paper analyzes hundreds of features proposed for the new technology, focusing on the open problems that can be solved by the researchers who want to contribute to the development of 802.11be.

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Current Status and Directions of IEEE 802.11be, the Future Wi-Fi 7

The ever-increasing demand for unlicensed spectrum has prompted regulators in the US and Europe to consider opening up the 6 GHz bands for unlicensed access. These bands will open up 1.2 GHz of additional spectrum for unlicensed radio access technologies (RATs), such as Wi-Fi and 5G New Radio Unlicensed (NR-U), in the US and if permitted, 500 MHz of additional spectrum in Europe. The abundance of spectrum in these bands creates new opportunities for the design of mechanisms and features that can support the emerging bandwidth-intensive and latency-sensitive applications. However, coexistence of unlicensed devices both with the bands' incumbent users and across different unlicensed RATs present significant challenges. In this paper, we provide a comprehensive survey of the existing literature on various issues surrounding the operations of unlicensed RATs in the 6 GHz bands. In particular, we discuss how key features in next-generation Wi-Fi are being designed to leverage these additional unlicensed bands. We also shed light on the foreseeable challenges that designers of unlicensed RATs might face in the near future. Our survey encompasses key research papers, contributions submitted to standardization bodies and regulatory agencies, and documents presented at various other venues. Finally, we highlight a few key research problems that are likely to arise due to unlicensed operations in the 6 GHz bands. Tackling these research challenges effectively will be critical in ensuring that the new unlicensed bands are efficiently utilized while guaranteeing the interference-free operation of the bands' incumbent users.

Next Generation Wi-Fi and 5G NR-U in the 6 GHz Bands: Opportunities and Challenges

IEEE 802.11ax-2019 will replace both IEEE 802.11n-2009 and IEEE 802.11ac-2013 as the next high-throughput Wireless Local Area Network (WLAN) amendment. In this paper, we review the expected future WLAN scenarios and use-cases that justify the push for a new PHY/MAC IEEE 802.11 amendment. After that, we overview a set of new technical features that may be included in the IEEE 802.11ax-2019 amendment and describe both their advantages and drawbacks. Finally, we discuss some of the network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other on-going IEEE 802.11 amendments.

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IEEE 802.11ax: High-Efficiency WLANs

Short time after the official launch of WiFi 6, IEEE 802.11 working groups are already designing its successor in the wireless local area network (WLAN) ecosystem: WiFi 7. With the IEEE 802.11be amendment as one of its main constituent parts, future WiFi 7 aims to include time-sensitive networking (TSN) capabilities to support low latency and ultra reliability in license-exempt spectrum bands. This article first introduces the key features of IEEE 802.11be, which are then used as the basis to discuss how TSN functionalities could be implemented in WiFi 7. Finally, benefits and requirements of the most representative low-latency use cases for WiFi 7 are reviewed.

Time-Sensitive Networking in IEEE 802.11be: On the Way to Low-latency WiFi 7

Next Generation Wi-Fi and 5G NR-U in the 6 GHz Bands: Opportunities & Challenges

Proliferating networking demands require the wireless local area networks (WLANs) to keep evolving. In May 2019, the IEEE 802 standards committee formally established the working group of the next generation WLAN: IEEE 802.11be. To satisfy the ultra-high definition video traffic and achieve the objective of extremely high throughput (EHT), multi-band operation (MB-Opr) is considered as one important technology. However, after deep analysis, simply adapting MB-Opr is not enough for the extremely high throughput requirements of IEEE 802.11be. This paper analyzes the possible schemes of AP coordination and full-duplex enabled MB-Opr, where AP coordination is also one key technology introduced by IEEE 802.11be. After that, we propose a MAC framework for AP coordination and full-duplex enabled MB-Opr that fits for all types of device capabilities. This framework is general enough that it has high scalability and good backward and forward compatibility. The simulation results confirm the performance advantages of proposed MAC framework and show that multi-band aggregation (MBA) and multi-band channel bonding (MBCB) outperform IEEE 802.11ax in throughput by 200% and 80.7%, respectively.

AP Coordination and Full-duplex enabled Multi-band Operation for the Next Generation WLAN: IEEE 802.11be (EHT)

Wireless local area network (WLAN) technology has become mature in the past few decades. However, with the development of social application forms, the situation of high-density deployment of cells has become more frequent in recent years, so the next-generation WLANs face the unprecedented challenge of quality of service (QoS) and quality of experience (QoE) of high-density cell users. In response to this challenge, The Overlapping Basic Service Set Power Detection (OBSS PD) mechanism and Spatial Reuse Parameter (SRP) mechanism are proposed in IEEE 802.11ax (Institute of Electrical and Electronics Engineers) to improve spatial multiplexing capability and certain throughput capabilities. But both of them possess inherent drawbacks. Based on this, this paper proposes an enhanced spatial reuse mechanism, named ESR (Enhanced Spatial Reuse), by limiting the value of the CCA threshold in the SRP mechanism to improve the quality of concurrent links, which further improves the average throughput. Compared to traditional SRP, simulation results show that ESR can increase throughput by 10% and reduce packet loss by 10%.

ESR: Enhanced Spatial Reuse Mechanism for the Next Generation WLAN - IEEE 802.11ax

Wireless LAN (WLAN) developed quite fast over the last two decades, and the next generation WLAN standard: IEEE 802.11ax will be released in 2020. IEEE 802.11ax needs to improve the performance and user experience under the ultra-high-dense deployment of cells. Thus, the concept of spatial reuse (SR) is introduced in IEEE 802.11ax by enabling more communication links to simultaneously transmit. This paper proposes an environment sensing based link adaptation algorithm (ESBLA). ESBLA introduces intelligent environment sensing and identifies the environment into several types: nice environment, serious collision, and severe channel fading. After that, ESBLA adjust the media access control (MAC) layer transmission strategy according to the sensed environment type. The simulation results show that ESBLA can reduce the impact of intensive deployment interference as much as possible while guaranteeing high throughput.

Yuan Yan

Papers

AP Coordination and Full-duplex enabled Multi-band Operation for the Next Generation WLAN: IEEE 802.11be (EHT)

ESR: Enhanced Spatial Reuse Mechanism for the Next Generation WLAN - IEEE 802.11ax

Environment Sensing Based Adaptive Acknowledgement and Backoff for the Next Generation WLAN