LPWAN - 5 letters in the heart of the IOT revolution

Explanations & Status of deployments in Belgium (2018).

If the Internet of Things revolution is still in its infancy, it is an undeniable fact. LPWAN technology will be, in history, a major turning point in the networking of all objects, whether used by the consumer and citizen (Smart Home, Smart Cities …), or by the companies (Smart Metering, Smart Industries …).

Until now, when it comes to connecting an object (a machine, a vehicle …) to know its status, its location, or interact with it, the only global solution – a global geographical coverage, national, even international – consisted of equipping it with a SIM card, and using the GPRS / 3G network of a telecom operator. The problems of this technology, commonly called M2M (Machine to Machine), are known:

  • Expensive equipment: difficult to find a 3G modem less than 20-30 Euro …
  • Very high energy consumption, requiring either a permanent power source (and therefore a wiring) or a powerful battery, making the size of the sensor incompatible with many use cases
  • Large footprint
  • A subscription cost, for connectivity, not insignificant, related to the need for a radio network (antennas operators) dense and expensive.

It is therefore difficult, with the M2M, to connect small objects, or not having an electric source. Or to accept that the sensor costs more than the connected object itself … Not to mention that it is undesirable for health, given the power of emissions, to carry a connected object in 3G, 24 hours a day …

LPWAN - Low Power Wide Area Network

It is in this context that LPWAN – Low Power Wide Area Network – technologies have emerged. The objectives of this technology are to propose sensors

  • Cheap – in the end only a few euros …
  • Small sizes – a few centimeters away, or less …
  • Can operate on battery, with great autonomy (5-10 years!)
  • Optimized to communicate for very small data rates, for a few Euro cents a month

If the LPWAN technology is not recent, with already implemented in the 90’s (for example the AlarmNet network in the United States), it will be necessary to wait for the creation of SIGFOX (2009) and the launch of its first network in 2012, in France, so that it begins to be structured and to become popularized.

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LPWAN's "historic" actors: SIGFOX and LORA

2 main players share the market today. On the one hand the historical actor, SIGFOX, French company of Toulouse. And on the other hand, LORA, an open protocol based on the chipset of the American company SEMTECH (whose technology was also initially developed in France). The French origin of these two options explains the presence of a strong ecosystem in France and in neighboring countries, including Belgium.

While the market approaches of SIGFOX and LORA are different, they are, on the other hand, very similar from a technical point of view. Both operate on the same ISM 868 Mhz frequency band (in Europe), unregulated frequency. Data transmission can be done over long distances, up to 15-20 km!, While the GSM network is based on a network of antennas separated by a few kilometers at the most … This allows to deploy a network more quickly, and cheaply! The principle is that the sensor (SIGFOX or LORA) broadcasts data packets, which are received by all antennas in view. A consolidation is performed by the network, which then communicates the unique message to any platform dedicated to data processing via a “callback” mechanism.

The fact that this frequency band is free imposes restrictions on its use. No more than 1% use of the frequency band for a sensor. This translates to a maximum of 140 useful 12-byte messages (“payload”) that can be sent via the SIGFOX or LORA network from the sensor (uplink). Sending data to the sensor (downlink) is very limited, however. 4 messages of 8 bytes (“payload” useful) per day maximum for SIGFOX.

Also to know … As the frequency is not regulated, it means that interferences between users can exist, which poses a problem as to the guarantee of Quality of Service (QOS). This is one of the arguments put forward by the promoters of the competing NB-IOT technology (see below), which operates on a regulated frequency, so without interference …

The new entrant: NB-IOT

The traditional Telecom Operators offering data communication (GPRS, 3G, 4G …) took a long time, before realizing the interest of proposing an LPWAN solution. For 15 years, they have been fighting to increase communication speeds, from GPRS – which was equivalent to our good old telephone modems – to 3G and 4G, now allowing you to watch television on your mobile. This race for performance has had a direct impact on the price of sensors, and on power consumption, which is only increasing. 15 years ago, we had to charge our Nokia phone every 2-3 days. Today, a last generation iPhone does not take a day … 4G is partly responsible. Supporters of all at 4G (and soon 5G) will tell you that the energy cost, per kilobyte, decreases. But for many cases of IOT application – consuming very little data – (for example a measurement per day in a case of telemetry), this argument does not hold water …

Studies have shown that LPWAN technology is ideal for more than 50% of the IOT (50-100 Billion) sensors that will be deployed in the years to come!

In June 2016, the 3GPP (standardization body of the GSM standard) announced the arrival of NB-IOT, in a statement

“It took us only 9 months to standardize the new technology after the study phase. Once again 3GPP demonstrated the ability to quickly respond to the emerging market needs” Dino Flore, the Chairman of 3GPP RAN, said.

NB-IOT is the response of traditional Telecom Operators to new entrants such as SIGFOX and LORA. It was time because operators could not afford to miss the IOT wave carried by LPWAN technology.

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NB-IOT, for Narrow-Band IOT, is based on the same objectives. Offer a connectivity solution with lower throughput, and very low power consumption. NB-IOT offers a bitrate of 20 kbits / second, so less constraining than SIGFOX or LORA. But probably at the cost of greater power consumption despite everything.

The content of this article is taken from a report “The LPWAN Networks for Internet of Things”, which can be downloaded free of charge here below. This report includes the contents of a module of the training “IOT Business Training” intended for Companies that plan – strategically or operationally – to deploy solutions related to the Internet of Things. This training covers all aspects of the Internet of Things: use cases, business models, IOT networks, security, sensors, project management .

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Free LPWAN Report

  • LPWAN - Low Power Wide Area Network
  • SigFox, LoRa, NB-IOT
  • Strengths and Weaknesses of SigFox, LoRa and NB-IOT?
  • State of IOT networks in Belgium?