WiFi 6 – the Ultimate IoT Solution?
Globally, the number of Internet of Things (IoT) devices is forecast to nearly triple from 9.7 billion in 2020 to more than 29 billion in 2030, according to Statista. Companies across markets, in particular the automotive, logistics and it industries, are investing in IoT solutions for the measurable advantages they bring, including improved operational efficiency, reduced costs and real-time, remote monitoring capabilities. But what’s driving IoT innovation and empowering it to deliver real-world value? Read on to find out.
WiFi and low-power devices
WiFi is not the first-choice protocol when you think about low-power embedded devices – it is rather associated with high-throughput media devices like smartphones or TVs. However, it may change in the near future, as vendors are releasing chips that have the WiFi 6 power-save features enabled. But why are we talking about WiFi 6, when WiFi 7 has already been announced? And what about earlier versions of WiFi? What actually makes us think it may be a gamechanger, when a lot of wireless protocols like BLE, Thread, or Zigbee are already commonly used? Let’s take a look.
802.11ax or WiFi 6?
The first WiFi protocol was announced in 1997 and was called 802.11. From there, we walked a long way – for about 20 years the naming of next generations of WiFi were indicated by small letters appended to the original 802.11 – a,b,g,n,ac. Finally in 2018 somebody from the IEEE (Institute of Electrical and Electronics Engineers, who are the designers of the protocol) was apparently fed up with technical nomenclature and made the name easier for non-technical users. That’s how WiFi 6 was born. It was definitely a good move, as it is now easier to distinguish between WiFi versions, no need to remember that 802.11a is actually newer than 802.11b, which is not intuitive. Also, the naming was introduced backwards, but nobody is using the term WiFi 1 or WiFi 2 now.
What is so special about WiFi 6 for IoT?
IoT devices are often battery-powered and hence use low power protocols to communicate. The most popular ones now are Bluetooth Low Energy, Thread, NB-IoT, Zigbee, Sigfox or LoRa. An edge device is needed to use most of the above-mentioned protocols – you cannot connect your BLE or Thread device directly to your home router – some protocol translation is necessary. Also, if you ask your friend who is not interested in new technologies about the list above, he will probably only have heard about Bluetooth, and only because he uses wireless headphones or audio streaming in a car. And WiFi? Everybody knows WiFi; everybody uses it on a daily basis. Infrastructure for WiFi devices is ready and it is only matter of time when all routers will support WiFi 6 or higher.
There have already been 39 billion device shipments over WiFi’s lifetime, with more than 4.4 billion WiFi devices expected to ship in 2022 alone. More than 50% of them would be WiFi 6 products – and it’s predicted WiFi 6’s share of devices will continue to grow in the coming years.
Of course – it doesn’t mean that WiFi is the magic solution for every use case you can think of – it’s just the most popular one. It’s in a similar situation to the MP3 format, whose popularity results in a market monopoly, though you can find many file formats with better quality. WiFi will still have a single point of failure, as with all star topology protocols. Nevertheless, it is nice to have a wider choice of technologies when designing a solution.
What new features of WiFi 6 are the most important for the IoT world?
Lower energy consumption
Target Wake Time (TWT) is a feature originally introduced in WiFi HaLow (802.11.ah) and adopted in WiFi 6. Without going too deep into technical details, TWT enables WiFi clients to avoid staying active for long periods of time (which is power-consuming) by scheduling the windows of active time for each client. In plain words, TWT eliminates collisions and chaos in the air – each device has its own window when only it communicates with the access point.
Lower collision rate
Basic Service Set (BSS) coloring is yet another feature adopted from WiFi HaLow. BSS is just a set of devices and an access point in one network. With WiFi however, you have limited channels available, so it may happen that several access points are communicating on the same channel and thus overlapping. If a client is just on the border of one BSS and another (shown in the figure) then every transmission by any device in both service sets will cause huge interference and noise on the channel. In dense environments, this is really a serious problem. BSS coloring is just a field in the frame preamble that adds ‘color’ information to a BSS, which enables devices (when detecting noise on their channel) to recognize whether ongoing traffic is inside their or another BSS operating on the same channel. What is the value of such information when still operating on the same channel? To put it briefly, WiFi uses a CSMA/CD protocol to handle collisions, and some predefined thresholds of signal strength decide whether the channel is busy or not. Having information about the ’color’ of the BSS empowers a device to manipulate those thresholds and not wait forever until a BSS in range will transmit. This can be huge improvement, especially if you imagine that most routers use channels 1,6 or 11. And what about you? When was the last time you changed the channel on your router?
The last improvement that matters for IoT is orthogonal frequency-division multiple access (OFDMA). So far, this feature has been implemented in LTE networks for downlink transmissions. In WiFi 6 it is used for both uplink and downlink transmissions. How does it work? In legacy WiFi versions, in order to communicate, the client engages with the entire channel frequency spectrum, as uses several subcarriers. In WiFi 6 you only need a part of a spectrum for a single device to communicate. In this way a lot of congestions and collisions can be avoided and, as a consequence, latency is lower. It is crucial for time-sensitive use cases and this improvement is also important for more dense environments.
Security in IoT was neglected for a long time, probably because the market was growing so quick and it was more important to have a working device over a secure one. But now everyone is aware that IoT devices have to be as secured as the rest of a digital infrastructure, otherwise they are an easy entrypoint for attackers. WiFi 6 introduces a long awaited WPA3 which replaces a vulnerable, 12-year-old WPA2. It is a massive security upgrade that enhances cryptography, blocks brute-force attacks and shores up a lot of vulnerable points.
WiFi 6 enables new quality for IoT devices. It introduces improved security, longer battery life, higher throughput and lower latency. The biggest benefit in applying WiFi 6 solutions can be seen in dense environments, where you can observe performance issues and poor quality of service. However, it is not perfect for every use case – there are still use cases where Thread (using mesh instead of star topology) would fit better. However, the popularity of WiFi protocol is increasing in comparison to other protocols, and in the near future we will see whether it also conquers the IoT world. The numbers leave no doubt – between 2016-2021 the number of WiFi devices in the world almost tripled, reaching about 23 billion. For comparison, the number of BLE devices between 2013-2020 increased from 1.7 million to just over 8 million. This is truly a different scale.
WiFi 6 is just one of many important IoT innovations that businesses implement to gain advantage over their competitors and reshape their markets. To create evolutive devices and solutions, organizations reach out to reliable software partners like Software Mind, which offers wide embedded services expertise and skilled, international talent. Get in touch via the form to talk with our experts about boosting your development capacity.