Last week the Wireless Broadband Alliance [WBA] brought out the latest updates from their Wi-Fi HaLow programme in a new white paper titled “Wi-Fi HaLow for IoT”.

HaLow (following the IEEE 802.11ah standard) intends to deliver a Wi-Fi version suitable for supporting IoT devices in a range of scenarios. The properties of HaLow allow it to support devices with some improved technical specifications, such as increased device density, better battery life and better penetration. These, the report points out, are all stumbling-blocks to the use of other Wi-Fi platforms to support IoT.

However, it is also designed with improved security features and with a focus on easy installation and management, which are critical for encouraging adoption with end-users.

As well as pointing out the specific features of the technology which will, in principle, allow it to function in a variety of use cases, the white paper sets out a range of real-world tests which WBA members are now going to undertake. These will use HaLow to support applications for smart homes, building automation, smart cities, retail, industrial IoT and agriculture.

The intention is to use the results of these tests to develop best practices for end users on how and where to deploy HaLow. As the white paper notes,

“Each scenario will highlight how Wi-Fi HaLow solves connectivity problems, which previously may have required non-standard RF radio technology, or incurred higher costs of ownership.”

While the latter point could be construed as a dig at cellular technologies, the report cites that, of the 10 billion IoT devices in operation during 2020, 7 billion of them were using close-range systems such as Bluetooth and Zigbee as well as various forms of Wi-Fi. In practice these are much more likely to be the primary targets of opportunity – in a perfect world for HaLow, later versions of those devices would concentrate around a single standard.

Band of Gold

One of the more striking things about HaLow is that it operates in a lower frequency than previous Wi-Fi standards, which enables it to deliver better penetration through walls, windows and other obstacles. It works in the sub-1GHz band reserved for “industrial, scientific and medical [ISM]” services according to the ITU. Exactly where that frequency band lies varies a little regionally, but within the range of 823 to 928MHz.

We have traditionally seen a trade-off between speed and penetration when it comes to coverage, so it would be easy to expect that HaLow would deliver less throughput than, for example, Wi-Fi at 2.4Ghz. While the report does not go into detail on this, it does point out that the 2.4GHz band today can be highly congested, with not only Wi-Fi but Zigbee, Bluetooth, Thread and other proprietary technologies compete for this spectrum band.

By offloading to a lower frequency but with less congestion the performance difference in practice may be less significant than the specifications alone would suggest… at least until there are enough HaLow devices out there to replicate that congestion.

Another element not mentioned in the report is quite how many devices out there are also operating in that ISM band. What are the risks of interference with, for example, glucose monitors or personally-worn devices, or industrial control systems?

Wi-Fi in a Near Field

While many of the scenarios outlined for the use of HaLow are fairly understandable extensions of existing use cases such as in the home, in retail or industrial environments, it is striking to see agriculture also on the list. This is a market already served by systems based on NB-IoT, sigfox, LoRaWAN and other standards.

The report authors make the case that the agriculture market may be a good opportunity based on the capabilities that HaLow offers, such as its scalability, range and penetration through vegetation. Soil or humidity sensors, actuators for irrigation and so on could use HaLow over the distances covered by typical crop farms, they explain.

However, all of this is already being addressed by other systems which have a headstart in terms of deployment on an increasingly wide scale. Arguably the most telling point in its favour may simply be compatibility with existing Wi-Fi systems and the familiarity that end users have with that (up to a point).

Can that familiarity overcome the existing economies of scale enjoyed by other systems? It will be interesting to see, but compared to other scenarios where Wi-Fi is already a contender this might be a stretch too far for the foreseeable future.

To access the WBA’s white paper visit their site here. While you may be asked to login to the site, the white paper is free to access.