Bluetooth Low Energy, WiFi 6 and the future of IOT

Bluetooth Low Energy is arguably the technology that “launched” the Internet of Things. The issue with “classic” Bluetooth was that it needed a continuous connection, which in turn meant it had rather limited battery life, and thus battery powered devices required frequent recharging. It also limited the use cases for which it could be easily deployed.

Bluetooth Low Energy fixed these issues by putting devices to sleep between transmissions whilst maintaining their connection. It also allows easy ad-hoc pairing. Alongside various other technical enhancements, this enabled the deployment of a large number of low power devices, sharing relatively modest amounts of data, but in the process vastly enhancing widespread connectivity.

The trend of WiFi has been in a different direction up till now – mainly focused on ever faster data rates to allow for high-definition content streaming and serving the needs of “cloud” based computing. Power consumption hasn’t been a major consideration and issues around spectrum not the main concern either. The target market was a relatively small number of big powerful devices sending a lot of data around.


See the original article in CIE Online here

You could say that WiFi was like the Sledgehammer and Bluetooth Low Energy the Scalpel – different tools for different jobs

New Bluetooth developments

However, new developments in both technologies are starting to take them in converging directions. On the Bluetooth side, the data rate increased with the version 4.2 and version 5.2 introduced streaming capabilities for Audio, alongside a new CODEC. This isn’t quite High Definition videobut it takes Bluetooth Low Energy away from its IOT data-based roots.

WiFi 6 brings new capabilities

On the WiFi side, WiFi 6 is a development aimed squarely at improving WiFi’s capabilities for IOT solutions. As mentioned above, previous iterations of WiFi were all about speed. This has been achieved by wide band channels. The flip side of this is that there can’t be very many of them in the limited spectrum allocated for free-to-air use. This doesn’t matter so much if one or two users are streaming from a home router, but as anyone who has used a public WiFi service in a busy area will know, networks can easily get saturated.

WiFi6 therefore borrows a few tricks from the cellular world and splits up the spectrum into sub-carriers, that allows for a larger number of users to transmit simultaneously, albeit at a lower data rate. These can be quite flexibly used, so different users can use be allocated different numbers of resource units across the same time period, depending on need.

A further enhancement is the implementation of “Target Wake Time” – whereby devices can request to wake up again after a defined time interval and drop into sleep mode in between. This is very much aimed at reducing the minimum level of power consumption required for a WiFi device.

How ODFMA splits up subcarriers to optimise spectrum use

To further enhance the capabilities of WiFi in dense environments, MiMo antennas are included at both ends of a connection, to allow spatial network sharing. Additional features enable overlapping networks with weak signals to be ignored.


All of this pushes WiFi firmly into the IOT domain – dense networks, flexible data usage, allowing battery powered devices using limited amounts of data – all of this sounds pretty much like the pitch that Bluetooth Low Energy made 10 years ago.

Bluetooth Low Energy & WiFi 6 – competitors?

So what does it add up to? Are these technologies now “competitors” where one will “win” and the other “lose”.

Not quite I think. There is clearly some moving together.  Both are more firmly than ever aimed at diverse IOT applications. There remain significant differences however – Bluetooth Low Energy still offers far better low power characteristics than WiFi 6 and the data rate capabilities of WiFi still far outstrip Bluetooth. Bluetooth frequency hopping technology will still prove more resilient in noisy environments and ad-hoc connectivity is still going to be easier using Bluetooth.

A convergence would perhaps be a better way of putting it. IOT applications are becoming more sophisticated and often one radio technology is not enough. One flip side of the advances in WiFi 6 is that the router must become an even more complex device than ever, managing more connections with differing demands. The MATTER home automation standard is a good example of trying to manage different radio standards under one umbrella. This standard might envisage using WiFi for large volume data exchange and Bluetooth for local device configuration.

It is notable that Nordic Semiconductor, the market leader in Bluetooth Low energy, has recently launched its first WiFi device. So one can expect that there will be a few dual radio devices coming out soon supporting the latest generation of both technologies.

Choices for system designers

For system designers, it is likely to be less a question of choosing one or the other, but in many cases, more what system functions should use which wireless technology.

One could make an analogy with the evolution of mobile phones – initially, they only had a connection to the cellular network, and over time, they turned into the multi-radio devices we carry around today. IOT applications are going the same way, having started with typically a simple point to point connection from the device to something acting as a gateway. We now have many different solution architectures including multi-radio, mesh networks, long and short distance, and various other permutations.

The bottom line is both technologies are adding capabilities, and this simply makes more things possible. Neither seems likely to disappear in the foreseeable future.


By: Dr Nick Wood, Director, Sales & Marketing, Insight SiP


Insight SiP
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