Wi-Fi Alliance 802.11ax

0
252
Wi-Fi Alliance 802.11ax

IEEE & Wi-Fi Alliance 802.11ax 

With around 18 billion Wi-Fi devices shipped, 8 billion still in use and 3 billion new ones added every year, it is difficult to find anywhere without a Wi-Fi signal.

Even cellphone networks, which have been improving speeds and capacities with the LTE build-out, small cells and flat-rate data plans, rely on Wi-Fi to meet the traffic requirements of their subscribers. A cellphone today without integrated Wi-Fi would be unthinkable.

Wi-Fi standards originate in the Institute of Electrical and Electronics Engineers (IEEE), where the 802.11 working group meets 6 times a year, with many interim conference calls for specialist task groups, to update and extend the technical standards that underpin Wi-Fi.

Once the IEEE has completed the standard, the focus shifts to the Wi-Fi Alliance, the industry trade forum that owns the ‘Wi-Fi’ trademark, where a series of plugfests support the drafting of a test plan and interoperability certification program. This is how the industry ensures that Wi-Fi clients work with Wi-Fi access points, across all the different vendors in the ecosystem.

The last major ‘PHY’ or physical-layer certification was 802.11ac, with ‘wave 1’ commercial shipments commencing in 2014 and ‘wave 2’ shipments in 2016. But the work on 802.11ac goes all the way back to 2008: the gestation period for this work can be long.

So it was that, even before 802.11ac wave 2 equipment started shipping, the IEEE started work on the next ‘PHY’ standard, designated ‘802.11ax’. The project formally kicked‑off in March 2014, and as of early 2018 is progressing through a series of ‘letter ballots’: the scope of the standard is now set, and with each revision the details become increasingly solid.

Final approval in the IEEE is expected late in 2019, but the standard will be effectively frozen many months before that.

Earlier physical-layer amendments to 802.11 set a precedent where the Wi-Fi Alliance started its work in parallel with the IEEE, accelerating time-to-market, and 802.11ax follows this timeline: work on a ‘Wi-Fi CERTIFIED AXTM’ certification program is already underway; the first plugfest was in early 2018 and the certification is expected to launch some time in 2019.

This overlap of the certification path with the standardization effort is important to shrink time-to-market, and as the standards organizations and equipment vendors have experience with prior physical-layer amendments, the risks are understood and can be minimized.

Design Goals of 802.11ax

When deciding how to improve Wi-Fi beyond the current release, 802.11ac, the IEEE and Wi-Fi Alliance surveyed Wi-Fi deployments and usage, to identify impediments to wider use and causes of dissatisfaction among user communities.

The conclusion was to depart from previous upgrade paths, which advanced peak data-rates under ‘good’ field conditions, and to focus more on ‘actual’ field conditions, and how to improve not just peak performance, but average and worst-case performance in real-world conditions.

These real-world conditions have changed over the years, due in no small part to the success of Wi-Fi. Access points are everywhere, even covering many outdoor spaces. In many areas, congestion has become a serious problem.

Examples include busy airports and train stations, multi-dwelling apartment buildings and even school and university settings. All are characterized by overlapping coverage from many access points, whether managed in the same network or uncoordinated, all serving many data hungry client devices.

So the IEEE and Wi-Fi Alliance set out to improve performance for everyone, especially in areas of overlapping coverage. In some places, interfering signals can be reduced by coordinating between access points, while in others, protocol enhancements make the Wi-Fi signal more resistant to interference.

But Internet service for cellphones and PCs is not the only use for Wi-Fi. The growing market for Internet-of-Things (IoT) sensors is using Wi-Fi for connectivity in many places, but a few limitations have restricted its adoption.

So new features in 802.11ax allow efficient allocation of low data-rate connections, improve the battery life of IoT sensors, and extend the range of Wi-Fi signals.

Wi-Fi is also used by wireless Internet service providers (WISPs) and for outdoor point-to-point links, and here 802.11ax includes features to extend range, increase data‑rates and reduce the effects of interference