Which wireless technology will win the lightweight WAN battle? - Embedded.com

Which wireless technology will win the lightweight WAN battle?

There are several alternative technologies being promoted as lightweight wide area networks (WANs). These include LoRa, Sigfox, Ingenu and Weightless along with some other radio standards that, to a greater or lesser degree, cover the same technical ground. It seems unlikely all of these will survive. Which will emerge as the winner?

I take the term “lightweight WAN” to mean those using open spectrum, which in practice is the ISM bands around 400MHz, 900MHz and 2.4GHz. Precise bands and rules vary by region across the world.

The advantage of these networks is that they do not require users to pay for expensive licensed spectrum. They typically target applications where the data rate needed is low and often with a low power requirement, meaning potentially battery powered. This is a segment that, at least for a long time, was not well catered for by traditional cellular solutions, with the focus of cellular development being firmly on ever higher data rates. The lightweight WANs are also mostly targeted at “uplink” communication – end nodes sending data to a server – although some downlink can be achieved.

From a technical perspective, the different technologies are variations rather than radically different solutions. There is an inescapable trade-off between range, power consumption and data rate. If you increase range, you will either increase power consumption or have to dial down the data rate or a mixture of the two. Nobody has yet defied the laws of physics.

Sigfox sits at the long range/low power/ultra-low data rate end of the scale with Ingenu at the other end. LoRa and Weightless are positioned between them. LoRa gives some degree of flexibility within the standard as its radio can adapt data rate dynamically to trade data rate for range.

Strengths of LoRa vs. cellular data for IoT. Also included for reference is Bluetooth (Image: Insight SiP)

Despite these limitations, a wide range of applications are well aligned to these technologies. Remote reading of sensors, meters or other measurement devices often require only sending a few bytes of data at infrequent intervals. Yet they can bring real value-add.

What is perhaps more interesting than technical differences are the different business models adopted around the differing standards, who owns what and what your options are for deploying a solution. It is here that I believe LoRa has found the right mix to succeed.

SigFox is aiming to provide it all, more or less. It runs the networks or licences others to do so and owns the patents on the radio technology. It would be the equivalent of a single monopoly mobile operator that also owned the relevant 3GPP standard.

This one stop shop approach is both a strength and a weakness. The strength is that you just have to buy an end device and Sigfox will look after the network side for you. The weakness is that you are totally dependent on Sigfox as a company. There is no competitor to move to. And Sigfox is not a big company. Whilst it has raised some $300M, it has struggled to meet its own targets and arguably is simply trying to cover too much ground with a global service. Whilst I am in no position to present in-depth financial analysis nor as a private company is there much data available, it would seem fair comment that Sigfox has yet to reach a position of strength and stability.

Ingenu is taking much the same approach, although it is even smaller and really only operates in the United States. It therefore shares the same pros and cons.

Weightless sits at the other extreme here, being an “open-source” project. There is a Weightless SIG, and an open standard, but it is less clear who is really driving this technology. There also seems to be a limited number of devices available on the market.

LoRa is located somewhere between these extremes. Originally developed by French company Cycleo, the LoRa radio modulation is now owned by Semtech. Hence, while Semtech supplies LoRa radio transceivers, more recently it has also licensed the technology to other vendors. So at the physical layer, the technology is proprietary.

However, for the network side, it is effectively completely open. The LoRa Alliance is an open industry body that defines LoRaWAN, a network protocol. Anyone can operate a LoRa network.

Traditional network operators, startup operators and some open networks run by local government promote the technology. In addition, it is possible to create your own network. There are several vendors selling low cost LoRa gateways. So for a large industrial site, for example, this might be an ideal solution. This also removes dependence on operator coverage if the site is in a remote location.

The practical outcome has been that a wide range of vendors have chosen to support the technology with modules, devices and gateways. So the end user has choice. Semtech remains the owner of the core radio technology. However, the company isn’t built around this nor does it show any sign of wanting to do any more than offer transceiver chips.

Clearly predicting winners and losers in technology is never easy. But in my opinion LoRa has the right balance, an established technology company driving the core technology and a diverse open ecosystem growing around it. Customers benefit from a lot of flexibility and choice, things that never really go out of fashion.

The bigger question is perhaps if any of these technologies can survive the oncoming juggernaut of cellular IoT. After years of neglecting the M2M market, the cellular world has woken up. With NB-IoT and LTE-M, it has launched a new generation of IoT focused technologies. Mobile operators have the size and power to heavily promote their technologies. However, even here, LoRa has the advantage of not directly competing with operators who can adopt LoRa and propose it themselves. Mobile operators also have the option of building private networks independently of others in the market.

A disadvantage of NB-IoT and LTE-M is that they both, to some extent, have a stronger emphasis on data rate than power consumption compared to the “lightweight” alternatives.

So whilst few things are certain in a fast moving and uncertain world, the flexibility of LoRa gives it the best chance of carving out a niche in the world of long range wireless IoT solutions, even if it is not clear what exactly that niche will be.

>> This article was originally published on our sister site, EE Times Europe.


Nick Wood is sales and marketing director at Insight SiP, an ultra-miniature RF module specialist. With a thirty year track record in the electronics industry, he previously researched fundamental physics at CERN and obtained a PhD in particle physics from University College London.

 

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