Low Power WAN

Low Power WAN – The Need

In my time as a Wi-Fi professional I have come across several customers who have attempted to formulate what can only be described as “Promethean” IoT (Internet of Things) solutions .   These customers typically have a requirement to measure some kind of data and transmit it back to a server somewhere where it can be processed.  The data gets measured infrequently, and it is small.  Perhaps a heartbeat, a status message, or a simple numeric value sent several times an hour.  The measurement locations are typically quite far apart or dispersed over a large area.

The customers had often looked at using GSM/UMTS/CDMA networks with sim-cards in the hardware, but getting a contract with a mobile operator ain’t cheap, the hardware gets expensive and it’s a recurring monthly cost!  Plus people break into your gear and steal your sim cards… or whatever other useful hardware might be in there!

After this experience, the customers would often come to me to discuss the possibility of using Wi-Fi as a potential solution to their problems.  To them it looked like the ideal solution!  This was a license free radio technology that got them away from the exorbitant monthly prices of mobile contracts, and besides, Wi-Fi radios are cheap, right?!  Looks like a possibility to me!

One such customer had gone out to tender for monitoring of an electrical grid.  Some spoke to me about smart electricity and water metering.  Others spoke about automation for agricultural applications.  Others wanted smart parking meters, smart street lights and air quality measurements.  Another even spoke to me about monitoring the location of livestock.

It was fun to engage with these customers to learn about what they wanted to do and to come up with creative solutions to their problems.  Sadly, there are often just too many problems associated with using Wi-Fi for these kinds of use cases.  The biggest issue (as with many things of a technical nature) ultimately boiled down to cost.   It simply isn’t cost effective to deploy a Wi-Fi network over an enormous area to gather small amounts of data.  The other issues include logistics, infrastructure, power, maintenance, security and internet or network connectivity.  All of these things would drive up the total cost and complexity of maintaining the solution.

Wi-Fi connected sensors themselves are usually power hungry, requiring a mains power or a solar panel, inverter, regulator, charging circuits and deep cycle batteries.  A decent regulator circuit alone can cost in excess of US $30 if you buy it in volume.  The devices also require a technical resource to configure and install them and make sure they associate to the network.  The total cost of deploying your “smart sensors” can quickly dwarf  the cost of the access network which itself already costs into the hundreds of thousands of dollars for an area as small as 10 square kilometres with contiguous coverage.

You want to track your livestock?  Yes! Could that make your operation more effective and help prevent livestock theft?  Yes!  Is it worth building a network across several thousand square kilometres, whose scale would rival that of a small ISP and cost you a small fortune to run?  No, it would bankrupt you almost instantly.

We always got to this point.  Don’t get me wrong, Wi-Fi is a fantastic technology, I have built my career on its myriad applications  and it is a very useful ally when building an IoT solution.  But even applications of the almighty Wi-Fi  have their (technical and financial) limits!

What the world needed was a set of protocols and radio technologies that enabled the use cases described above, in a simple, secure, effective way.  We needed something that could cover large rural areas (± 7500 km2) using a single tower, that could gather data from thousands or even millions of sensors in a dense urban environment, both indoors and outdoors.  And it needed to do this without making much of a dent in the bank balance.

The protocols and technologies that address this growing need today are collectively referred to as LPWAN (Low Power WAN) and its range of applications are growing extraordinarily fast!

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