Although the standard for the next generation of Wi-Fi technology hasn’t been officially finalized, that hasn’t stopped chipsets, reference designs and test equipment from making it to the market to support the transition to 802.11ax.
The 802.11ax ecosystem has begun picking up steam, with products from chipsets to access points — and the test equipment to make sure they work — making their debut this year.
Aerohive plans to deliver its first 802.11ax access points in mid-2018. PCTel said in January that it had developed a reference design for 802.11ax antennas for an unnamed “major 802.11ax Wi-Fi chipset manufacturer.” There’s a lot of chipset activity in particular, with Qualcomm already having launched its “802.11ax-ready” Atheros WCN3998 chipset in February and other companies like Intel laying out plans to begin offering chips this year. Chip company Skyworks is collaborating with Broadcom with modules integrated into Broadcom’s Max Wi-Fi 802.11ax solution and claims that its 2.4 and 5 GHz 802.11ax modules and Broadcom’s Max WiFi solutions “provide four times faster download speeds, six times faster upload speeds, enhanced coverage and up to seven times longer battery life when compared to 802.11ac Wi-Fi products available in the market today.” ABI Research has noted that in addition to those vendors, Marvell, Quantenna and Celeno have also made 802.11ax chipset announcements — mostly targeting the access point space — and that AP companies such as Asus, D-Link and Huawei have already put out 802.11ax-ready APs and gateways.
How is 802.11ax different?
802.11ax is expected to make improvements to Wi-Fi in a few areas, but it’s a bit different than previous new Wi-Fi standards — which often focused on delivering faster peak speeds. 802.11ax is also aimed at delivering greater Wi-Fi speed, but does it through making capacity improvements in congested network environments, by supporting more users in dense networks and making more efficient use of spectrum.
As Anritsu Product Manager Mike Barrick explained, the difference between 802.11ax and previous Wi-Fi generations may not be very noticeable for a residential Wi-Fi user, compared to the improvements in a dense network with many users.
“It won’t necessarily affect the performance of a single user on a single AP, like if you’re sitting in your house,” Barrick said. In developing the standard, he added, “they did a bunch of things to increase the capacity. The goal is to increase the data rate in a congested environment by 4x or more.”
802.11ax also offers significant power usage improvements. Qualcomm, for instance, claims that its WCN3998 chipset reduces Wi-Fi power consumption by up to 67% compared to 802.11ac Wave 2.
Adam Smith, director of product management for Litepoint, noted that the company has had a pre-standard 802.11ax testing solution available since late 2016 to enable early development, with software upgrades to stay current with work and enable compliance with the final standards whenever it’s released. Litepoint’s IQxel-MW for 802.11ax testing has been used by Broadcom to validate designs, and Litepoint has called 802.11ax “the most complex Wi-Fi standard in history.”
To this point in Wi-Fi evolution, Smith noted, the technology has been based on one-on-one device-to-access point conversations. 802.11ax changes that to multi-user simultaneous support. Smith said that the capacity increases will make for a better user experience, with 10x more users able to be supported. Multi-user MIMO in use in 802.11ac hasn’t achieved its full commercial deployment potential and “is not that granular — it’s really rough,” and based on beam-steering. In contrast, 802.11ax makes Wi-Fi more like cellular through the use of OFDM, scheduling and spatial re-use, according to Litepoint.
Barrick agreed.
“All those changes move it closer to what LTE is today,” Barrick said. “At the same time, cellular is moving to 5G, but I think it makes [802.11ax] a better standard.”
Testing and standardization of 802.11ax
Testing 802.11ax offers up some unique challenges that Wi-Fi testing hasn’t previously had to navigate. One of those is synchronization of devices in the uplink using the AP, in order to avoid interference. A trigger frame is sent from the AP to the devices and they must respond for coordination of timing, frequency and power levels. Rohde & Schwarz gives some of the basics of uplink accuracy testing here.
This trigger-based testing is entirely new and the measurement is very detailed and intensive, Barrick said.
Smith said that the client software side of 802.11ax is much more complex as well.
“The majority of client devices, they’re flat-out not calibrated,” Smith said. Companies may conduct functional testing or do the bare minimum of double-checking their reference designs, he said, but few go to the point of calibration although it improves the overall user experience. In addition, Smith said that the increased numbers of Wi-Fi radios to support, say, 802.11ax along with 802.11ac and previous generations, at both 2.4 and 5 GHz, means that test times “could go up dramatically.”
Meanwhile, the path to a final standard for 802.11ax has been a rocky one, and the work is still ongoing. As Intel’s Dan Artusi, vice president of its client computing group and GM of Intel’s connected home division, noted in a blog entry, the standards work continues and the draft which is ultimately adopted — and on which certification is based — may differ enough from earlier drafts that product interoperability could be an issue. The next draft is expected to be voted on mid-2018, but it’s possible that finalizing the standard could take until 2019.
“In early 2017, we saw the publication of Draft 1.0 of the 802.11ax standard. However, that early draft accrued more than 3,900 open technical comments,” Artusi wrote. “Infrastructure devices—routers, gateways, and extenders—with chipsets based on Draft 1.x (successive revisions of Draft 1.0) may not be interoperable with client devices that have chipsets based on Draft 2.0, and vice versa. The potential interoperability issues could result in degraded throughput, decreases in network efficiency and increased interference that could create a suboptimal user experience.”
That creates some uncertainty for OEMs, according to Andrew Zignani, senior analyst with ABI Research.
“The question for OEMs is whether they should wait until the standard is more stable before adopting an 802.11ax-ready solution,” he wrote. “A wait-and-see approach could arguably result in a longer lead time, and some OEMs may lose out to those who are proactive in getting their designs ready for the full version of the standard. Some in the industry believe that due to the additional complexity of the 802.11ax standard, it is important to get 802.11ax chipsets into the hands of engineers sooner rather than later to help them build devices around the new features. If an OEM does decide to hold back, their first devices integrating an 802.11ax chipset may come 6 to 18 months behind that of the competition. the question for OEMs is whether they should wait until the standard is more stable before adopting an 802.11ax-ready solution. A wait-and-see approach could arguably result in a longer lead time, and some OEMs may lose out to those who are proactive in getting their designs ready for the full version of the standard. Some in the industry believe that due to the additional complexity of the 802.11ax standard, it is important to get 802.11ax chipsets into the hands of engineers sooner rather than later to help them build devices around the new features. If an OEM does decide to hold back, their first devices integrating an 802.11ax chipset may come 6 to 18 months behind that of the competition.”
Editor’s note: This story has been updated to correct the spelling of Dan Artusi’s name. RCR regrets the error.
