The Internet of Things (IoT) will only flourish if the right communications standards are in place to enable devices to talk to each other. Wi-Fi has a bigger role to play here than many realise, and the new 802.11ax standard will be important in supporting devices that need to run on low power.
Internet of Business spoke to Blaz Vavpetic, CTO at iPass, to find out more about 802.11ax and what it brings to the world of device-to-device communications.
Internet of Business: Can you explain in a nutshell what 802.11ax offers over 802.11ac, which it is likely to replace in most cases?
Blaz Vavpetic: “Where 802.11ac operates only in the 5Ghz range, 802.11ax operates in both the 2.4Ghz and 5Ghz ranges, creating more available channels.
“Having more channels makes it easier for endpoints such as IoT devices or smartphones to find a clear path to the access point.
“802.11ax supports full duplex multi-user, multiple input, multiple output (MU-MIMO) connections, allowing an access point to transmit to multiple devices concurrently, and endpoints to simultaneously receive from multiple transmitters.
“By contrast, 802.11ac supports MU-MIMO connections in downlink transmissions only. Having a full duplex capability makes the connection significantly faster.
“802.11ax has a range of other important features that are all aimed at improving efficiency. For example, OFDMA [Orthogonal Frequency-Division Multiple Access] helps divide up the spectrum to allocate bandwidth to different user requirements simultaneously.
“Other efficient access features include trigger-based random access, dynamic fragmentation, and spatial frequency re-use.
“Of particular interest to the IoT, 802.11ax also introduces a feature called Target Wake Time, which allows devices to operate on a schedule. If the device does not need to send or receive data, it can ‘sleep’ and conserve power. This capability will have significant implications for IoT devices such as industrial sensors that are low-power and low-complexity.”
802.11ax can cope with up to eight channels at a time, doubling the capability of 802.11ac. How does this benefit the IoT?
“The standard can support eight MU-MIMO transmissions at a time, up from four with 802.11ac. Supporting eight simultaneous channels and flexible, narrow, dedicated channel sizes, can give more IoT devices the opportunity to establish a clear path to the access point, and it avoids the bandwidth problems that existed in earlier versions of Wi-Fi, including 802.11ac. In the IoT, this will support more devices in high-density environments, especially in use cases that only require lower data rates.”
One of the benefits of 802.11ax will be its support for ‘subchannels’. Can you explain what these are, and how the IoT will benefit?
“802.11ax divides the existing 802.11 channels (20, 40, 80 and 160 MHz) into smaller sub-channels, with a predefined number of subcarriers. Based on multi-user traffic needs, the access point decides how to allocate the channel, always assigning all available resource units (the smallest allocation of bandwidth) on the downlink. It may allocate the whole channel to only one user at a time – just as 802.11ac currently does – or it may partition it to serve multiple users or devices simultaneously.”
How does 802.11ax manage to be more power efficient than 802.11ac, and how does this benefit the IoT?
Narrower channels and the introduction of Target Wake Time to improve wake and sleep efficiency, allow small, power-constrained devices with low bandwidth requirements to communicate very efficiently.
“Therefore, with 802.11ax, companies will be able to deploy a device with a Wi-Fi radio and keep it connected for far longer between charges, enabling Wi-Fi to become a cheaper alternative to GPS or cellular/SIM location data, and it doesn’t require a huge investment in hardware or software to work.
“This new Wi-Fi capability is leading to the emergence of complementary technologies that enable new IoT use cases. One such example is IoT location tracking, whereby a low-power, processor-constrained device can ‘report’ its location when it is connected to a nearby access point.”
Can you give three or four examples of how 802.11ax is likely to be used in real world scenarios?
“Location-based services in a shopping mall is one. 802.11ax will enable service providers to sell location-based services to retailers and those running shopping malls.
“For example, 802.11ax will make it possible to gather more reliable information about customer densities, the flow of customers through an establishment, and queue times, while also tracking assets such as trolleys. As an additional service, retailers would then be able to target advertisements based on people flow, as well as delivering appropriate content to users once they’ve been profiled.
Intermittently locating a shipping container is another. The power efficiency improvements in 802.11ax make it economically viable to use the global network of Wi-Fi hotspots to track low-power devices.
“For example, if a shipping company were to deploy a Wi-Fi radio within its container, they could use Wi-Fi hotspots to track its location. The Wi-Fi radio attached to the container would not need to log into the network or be an authenticated user, it would simply need to be in the presence of the access point.
“802.11ax makes Wi-Fi a more suitable option for this kind of use case. For example, if the container were to move indoors, it may not be able to get a GPS signal, but Wi-Fi location tracking would still work.
“Improved connectivity in high-density transportation settings is another example. In locations such as airports and train stations, where there is a very high demand for Wi-Fi from lots of users or devices, the 802.11ax will make it possible to greatly improve connectivity.
“For example, onboard an aircraft 802.11ax will be able to support multiple, separate services for different targets. It will be able to handle the connectivity needs of IoT devices and services in addition to passenger requirements, such as Web browsing or using the entertainment systems. The same is true for other vehicle scenarios, with multiple end users able to enjoy an enhanced throughput and experience.”
Internet of Business says
Pre-standard 802.11ax access points will begin showing up en masse in late 2018 or early 2019, although some are already on sale. Consumer devices supporting the standard will emerge in the second half of 2019, following IEEE ratification.