As the IEEE 802.11 project, forebearer of Wi-Fi, marks its 30th anniversary next month, Wi-Fi 6 (802.11ax) gear is just beginning to appear in the market, even as the spec awaits final ratification later this year.
But wireless networking boffins are already salivating at the prospect of Wi-Fi 7 (802.11be), the specification that's currently being developed. Its 1.0 draft spec is due in May 2021, to be followed by 2.0 in March 2022, 3.0 in November 2022, and 4.0 in November 2023, punctuated by a final version in 2024.
Still, it's not too early to be excited if Wi-Fi is your livelihood, which in a way it has become for everyone who relies on wireless connectivity amid the ongoing coronavirus pandemic.
In a paper [PDF] distributed through ArXiv, a quartet of boffins from Nokia Bell Labs in Dublin, Ireland, and Universitat Pompeu Fabra, in Barcelona, Spain – Adrian Garcia-Rodriguez, David Lopez-Perez, Lorenzo Galati-Giordano, and Giovanni Geraci – revisit the Wi-Fi spec planning process for technology that they cheekily rank as an essential, right after food, shelter, and clean water in Maslow's hierarchy of needs.
"While we would argue that humans do not need [the] internet more than breathable air, the importance of Wi-Fi is unquestionable," they write in "IEEE 802.11be: Wi-Fi 7 Strikes Back." "During forced confinement, many of us resorted to Wi-Fi to be in touch with our loved ones, to place online orders that kept small businesses afloat, and to keep fit by taking live streaming yoga classes."
Wi-Fi 7, they claim, will not only live up to its name – 802.11be Extremely High Throughput – but will offer a number of features that will help the technology address the growing demands being placed on wireless networks.
Bits and bytes
In terms of speed, Wi-Fi 7 was initially planned to support data rates of at least 30 Gbps per access point, compared to Wi-Fi 6 which can manage about 10 Gbps with eight antennas, 160-MHz bandwidth, and 1024 QAM (quadrature amplitude modulation).
A paper published in May, "Current Status and Directions of IEEE 802.11be, the Future of Wi-Fi 7," suggests it could be faster still, about four times faster than Wi-Fi 6, thanks to improvements in the physical networking layer. The plan is to double both the bandwidth (to 320 MHz) and the number of spatial streams in MI-MIMO, which multiplies the nominal throughput by a factor of four.
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With the addition of higher rate modulation and coding schemes that come from 4K-QAM (up from 1024-QAM), another 20 per cent improvement in nominal throughput is expected, meaning Wi-Fi 7 could muster a maximum nominal throughput of 46 Gbps. Bear in mind these are theoretical maximums.
"802.11be will focus on increasing capacity and link throughput in WLANs, and will also improve their latency and jitter," said Giovanni Geraci, assistant professor at UPF Barcelona and one of the paper's co-authors, in an email to The Register. "In other words, peak throughput improvements are the main target, as the name says, 'Extremely High Throughput.'"
Geraci said these goals will bring other benefits. "One example could be multi-link operations, where one could potentially use more bandwidth at once, but also could have more flexibility in how to use it, which may lead to a better end-user experience," he said.
If the spec can deliver lower latency and higher reliability, Geraci and his colleagues expect to see applications emerge that take advantage of the improved networking environment.
"The former is seen as an enabler for real-time applications including augmented and virtual reality, gaming, and cloud computing, demanding delay times reduced to below 5 ms," explain the networking boffins in their paper.
"The latter is critical for next generation factories and enterprises, where Wi-Fi may need to guarantee three or more 'nines' of reliability to aim at replacing some wired communications."
Wild West of spectrum
Coincidentally, there will be a larger playing field to achieve those goals at least in the US: The FCC decided [PDF] in April to approve the unlicensed use of the 6 GHz band. The Wi-Fi Alliance is expected to certify Wi-Fi 6E devices using the newly freed spectrum next year.
The first draft of 802.11be, Release 1, is expected to include support for multi-link operation, which should help realize both speed and latency ambitions. The spec will make the ability of modern chip sets to support multiple independent links more coordinated, more efficient, and less subject to interference amid dense deployments.
Under the new regime, multi-link devices will sport features like multi-link discovery and setup, traffic-link mapping, and more efficient power management capabilities. Wi-Fi 7 may also include coordinated spatial reuse (CSR), an improvement on the spatial reuse system introduced in 802.11ax.
"In CSR, a sharing AP [access point] that has acquired a transmission opportunity (TXOP) can trigger one or more other shared APs to perform simultaneous transmission with appropriate power control and link adaptation," the Wi-Fi 7 Strikes Back paper explains.
"This coordination will create more spatial reuse opportunities and reduce the number of collisions when compared with the spatial reuse schemes available in 802.11ax."
Release 2 is likely to gild the lily by doubling the maximum number of supported single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO) spatial streams to 16. It's also expected to see the introduction of Hybrid Automatic Repeat Request (HARQ), a scheme for devices to pass on (rather than drop) decoding errors to increase the chance of successful decoding, and to support various techniques for reducing latency and enhancing AP coordination.
Garcia-Rodriguez, Lopez-Perez, Galati-Giordano, and Geraci anticipate that demand for Wi-Fi and better wireless connectivity will continue to grow as more devices integrate networking capability, as more data gets collected and transmitted, and as more people rely on live video to work, learn, and interact remotely.
All this should mean Wi-Fi 7 is likely to get a warm welcome when it arrives. ®