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What awaits us in Wi-Fi 7, IEEE 802.11be?

Recently, devices supporting Wi-Fi 6 technology (IEEE 802.11ax), about which there is much talk, have entered the market. But few people know that a new generation of Wi-Fi technology is already being developed - Wi-Fi 7 (IEEE 802.11be). About what Wi-Fi 7 will be in this article.

The main features of Wi-Fi 7 (picture from the article https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9090146)

Background


In September 2020, we will celebrate the 30th anniversary of the IEEE 802.11 project, which has significantly affected our lives. Currently, Wi-Fi technology, defined by the IEEE 802.11 family of standards, is the most popular wireless technology used to connect to the Internet: Wi-Fi transmits more than half of user traffic. While cellular technologies are rebranding every decade, for example, replacing the name 4G with 5G, for Wi-Fi users, the increase in data transfer speed, as well as the introduction of new services and new functions, are almost imperceptible. Only a few customers care about the letters "n", "ac" or "ax" that follow "802.11" on the equipment boxes. But this does not mean that Wi-Fi is not developing.

One of the evidence for the development of Wi-Fi is a sharp increase in the nominal data transfer speeds: from 2 Mbps in the 1997 version to almost 10 Gbps in the latest 802.11ax standard, also known as Wi-Fi 6. Modern Wi-Fi reaches such performance gains thanks to faster signal and code designs, wider channels and the use of MIMO technologies .

In addition to the main focus of high-speed wireless LANs, the evolution of Wi-Fi includes several niche projects. For example, Wi-Fi HaLow (802.11ah) was an attempt to bring Wi-Fi to the wireless Internet of things market. Millimeter-range Wi-Fi (802.11ad / ay) supports nominal data transfer speeds of up to 275 Gb / s, although for very short distances.

New applications and services related to high-resolution video streams, virtual and augmented reality, games, remote office and cloud computing, as well as the need to support a large number of users with intensive traffic in wireless networks, require high performance.

Wi-Fi Goals 7


In May 2019, the BE subgroup (TGbe) of the 802.11 working group of the Committee for Standardization of Local and Urban Networks began work on a new addition to the Wi-Fi standard, which will increase the nominal bandwidth to more than 40 Gb / s in one “typical” frequency channel for Wi-Fi band <= 7 GHz. Although many documents feature “maximum bandwidth of at least 30 Gbit / s,” the new physical layer protocol will provide a nominal speed of over 40 Gbit / s.

Another important development area for Wi-Fi 7 is support for real-time applications.(games, virtual and augmented reality, robot control). It is noteworthy that although Wi-Fi specializes in audio and video traffic, for a long time it was believed that providing standard guaranteed low latencies (units of milliseconds), also known as Time-Sensitive Networking, is fundamentally impossible in Wi-Fi networks. In November 2017, our team from the IPPI RAS and the Higher School of Economics (do not count it as PR) made a corresponding proposal in the IEEE 802.11 group. The proposal aroused great interest, and in July 2018, a special subgroup was launched to further study this issue. Since real-time applications require both high nominal data rates and an extension of the link layer functionality, workgroup 802.11 decided to develop methods for supporting real-time applications within Wi-Fi 7.

An important issue related to Wi-Fi 7 is its coexistence with cellular network technologies (4G / 5G), developed by 3GPP and operating in the same unlicensed frequency bands. It's about LTE-LAA / NR-U. To study the problems associated with the coexistence of Wi-Fi and cellular networks, IEEE 802.11 launched the Coexisting Standing Committee (Coex SC). Despite numerous meetings and even a joint workshop of 3GPP and IEEE 802.11 participants in July 2019 in Vienna, technical solutions have not yet been approved. A possible explanation for such a fruitless activity is that both IEEE 802 and 3GPP do not want to change their own technologies to bring them into line with another. Thus, at the moment it is not clear whether discussions within the framework of Coex SC will affect the Wi-Fi 7 standard .

Development process


Although the Wi-Fi 7 development process is in its infancy, about 500 new features have been submitted to the future of Wi-Fi 7, also known as IEEE 802.11be. Most of the ideas are only discussed in the be subgroup and a decision on them has not yet been made. Other ideas have been recently approved. It will be clearly indicated below which proposals are approved and which are only under discussion.

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It was originally planned that the development of the main new mechanisms will be completed by March 2021. The final version of the standard is expected by early 2024. In January 2020, subgroup 11be expressed concern over whether the development would be on schedule at the current pace. To speed up the development of the standard, the subgroup agreed to select a small set of high-priority functions that can be released by 2021 (Release 1), and leave the rest to Release 2. High-priority functions should provide the main performance boost and include support for 320 MHz, 4K- QAM, obvious OFDMA improvements from Wi-Fi 6, MU-MIMO with 16 streams.

Because of the coronavirus, the group is now not going to attend in person, but regularly holds newsgroups. Thus, the development slowed down somewhat, but did not stop.

Technology details


Consider the main innovations of Wi-Fi 7.

  1. Wi-Fi 6 c 320 , MU-MIMO, 2x2 = 4 . Wi-Fi 7 4K-QAM, 20% . , Wi-Fi 7 2x2x1,2 = 4,8 Wi-Fi 6: Wi-Fi 7 9,6 / 4,8 = 46 /. , , Wi-Fi, .
  2. IEEE 802 TSN . , , , , .
  3. Wi-Fi 6 (802.11ax) OFDMA – ( , 4G 5G) – . 11ax OFDMA . -, . -, . . , Wi-Fi 6 OFDMA , . 11be OFDMA.
  4. Wi-Fi 7 , , . , , 2.4 5 , , . 11be , .
  5. , , MIMO OFDMA. . , .
  6. Wi-Fi 7 «» . , . (HARQ), , full-duplex (NOMA). , , , , , .
    • HARQ . Wi-Fi . Wi-Fi , , . HARQ , , , . HARQ Wi-Fi.
    • Full-Duplex, , Wi-Fi ( ), . . , , Wi-Fi , , , - , ( « » ). .
    • MIMO , . 5G. NOMA Wi-Fi 2018 . ( ). 30-40%. : , Wi-Fi 7. , Wi-Fi . NOMA MU-MIMO, . : IEEE INFOCOM 2020 .
  7. , , , . Wi-Fi, , , . , , beamforming ( ) MIMO. ( , NOMA). 11be , , , . , , (, MU-MIMO), , Release 2. . , . Wi-Fi c , HCCA (11e) HCCA TXOP Negotiation (11be).

In summary, it seems that most of the proposals related to the first five groups will become part of Wi-Fi 7, while the proposals related to the last two groups require significant additional research to prove their effectiveness.

More technical details


Technical details about Wi-Fi 7 can be read here (in English)

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