The Voice Of A Generation

The Power of Sigfox: Pioneering the IoT Revolution


What if there was an easy way to connect the physical world around us with the digital world? What if we could connect the simplest of things to the Internet and garner invaluable data as a result? That’s what Sigfox sets out to do, to connect millions of sensors to one network that boasts resilience, efficiency and security. Founded in 2009 in France, Sigfox has swept across forty-five countries around the globe and covers close to one billion people with its industry-leading coverage. In Ireland, the Sigfox network is operated by VT IoT, connecting everything from our shopping trolleys to our smoke detectors.

VT IoT provides 97% outdoor population coverage with its IoT network in Ireland (86% indoor population coverage), an unparalleled footprint that Vodafone or other networks would only dream of having. The company is engaged in an infrastructure sharing agreement with RTÉ’s networking branch, 2RN, that has allowed it to roll out the Sigfox network in just a few short years without the need to invest hundreds of millions of euro like mobile networks are forced to do every time a new generation of networks is over the horizon.

Sigfox and VT IoT certainly aren’t unchallenged internationally or in Ireland, Vodafone has hastily launched its own network for the Internet of Things called Narrowband-IoT (NB-IoT), which features fundamentally different characteristics than Sigfox. It is clear that mobile networks such as Vodafone are being beaten in their own game. It must be disturbing for Vodafone to watch new competitors build out their own network at a fraction of the cost and hoover up customers. Hence the reason we see the network pushing NB-IoT throughout Europe. Vodafone and other telecom companies across Europe are finding it more difficult to produce a profit as prices continue to fall, and IoT appears to be a lucrative new revenue stream for them.

Sigfox aims to connect simple things with a simple network. Without question, this is the most important aspect to understanding the purpose of the Sigfox network in the first place. Why do simple things such as sensors that provide data about temperature require a traditional cellular network to communicate? It doesn’t make sense, especially with the battery technology available to us today. Traditional cellular networks, such as the ones that allow you to make a call or stream Netflix on your phone, are unsuitable for connecting the millions of sensors that will interact with the Internet. Cellular networks consume too much power, rely on a constant connection to a base station and are too expensive.


Low Cost Allows Us To Connect More Things

A key benefit of using Sigfox to connect sensors is the fact that the network is extremely cost-effective. Compared to NB-IoT, Sigfox providers such as VT IoT are able to provide access to the Sigfox network for just a few euro a year. With NB-IoT, a subscription to the network is much more expensive and typically works with a monthly pricing structure. The difference in price is so extreme in many cases that one year of connectivity to the Sigfox network is less expensive than just one month of connectivity to an NB-IoT network. For a business, imagine how much more costly it would be to choose NB-IoT over Sigfox if the use case was compatible with both networks. The very sensors that connect to the Sigfox network are less expensive to manufacture than their NB-IoT counterparts, due to cheaper radio modules, PCBs, antennas and the absence of a SIM card.

The benefits of good pricing stretch beyond this, Sigfox is a global network for the Internet of Things and this means there is a unified pricing structure across its network. Unlike with NB-IoT, which is operated by different networks in different countries, the cost of accessing the Sigfox network in different countries is much more transparent. This is a gigantic benefit for multinational companies that operate businesses such as shipping. For a better idea of this, look at your mobile phone which is similar to NB-IoT networks. When you travel abroad and roam on other networks, you never know exactly how much it will cost you to use your phone, but you know that the networks will punish you for your use with extra charges. Sigfox operates very differently, if you enter another country, you will be charged the price for accessing the Sigfox network in that country, and won’t be hit by any extra charges.

The cost-effective nature of Sigfox extends to the network provider, in Ireland’s case, VT IoT. As mentioned earlier, deploying and operating a Sigfox network requires significantly less capital and operating expenditure compared to traditional cellular networks. Virtually everything is less expensive, from the equipment required for base stations to the spectrum utilised for the Sigfox network. In fact, as Sigfox uses unlicensed spectrum (868-868.2MHz), VT IoT doesn’t have to pay a penny to Ireland’s telecom watchdog. Compare that to Vodafone, Three and Eir, all of whom collectively pay ComReg millions to obtain a license to use the spectrum for their mobile network. Likewise, NB-IoT uses expensive licensed spectrum, a major reason why networks such as Vodafone choose to pursue this technology.

The Internet of Things promises to connect everything and this is why a cost-effective method of connecting devices is vitally needed. The cost-effective nature of Sigfox means millions of sensors can be connected to the Internet, kickstarting the IoT Revolution. There is no other way to put it, an IoT Revolution will never happen if there isn’t a cost-effective method of connecting things to the Internet, at the moment, Sigfox is the best method.

Low Power Consumption is a Paramount

Sigfox is an extremely energy-efficient method of connecting our devices to the Internet. Tiny sensors are powered by tiny batteries, in many cases, replacing the battery every few weeks or months is just not possible. Sensors connected to the Sigfox network can last for years, the same cannot be said with devices communicating with today’s NB-IoT networks. Think about smart metres, do we want to have to change the battery after a few weeks?

The energy-efficiency associated with Sigfox comes as a direct result of the unique design of the network which is vastly different than traditional cellular networks. An important factor that contributes to the energy-efficiency of Sigfox is the lack of need for synchronisation messages between the sensor and base station. When a sensor on an NB-IoT network sends a message, it requires a synchronisation confirmation, thereby consuming more energy. Another reason for the low power consumption is the fact that sensors connected to the Sigfox network are idle for most of their lifetime, only activating when they need to send a message or receive a downlink message from a base station. Once again, this is in contrast to sensors that connect to an NB-IoT network, which consume more power in standby due to a constant connection to a cellular network.

The power consumption of sensors connected to an NB-IoT network increases as the strength of the signal decreases. This is similar to the phenomenon that causes your phone’s battery to drain quickly when you experience poor network signal, the device needs to work harder to maintain a connection to the nearest base station. The same isn’t an issue with a Sigfox sensor as the power consumption is the same regardless of the signal strength or quality. This makes it easier to predict power consumption on the Sigfox network, in contrast to NB-IoT where power consumption varies wildly depending on the signal conditions.

For an example of the startling difference in battery life between devices connected to an NB-IoT network and those connected to the Sigfox network, let’s look at a tracker which makes use of GPS and WiFi for geolocation. Vodafone provides a bag tracker, V-Bag, which claims a horrible battery life of up to four days and connects to their NB-IoT network. A similar tracker from a company called Invoxia can last for up to six months as it accesses the Sigfox network. The Invoxia tracker is also significantly less expensive over time, which would you buy?

Of course, as with any technology, it will improve with time. Without question, NB-IoT will become more energy-efficient over the coming years. But it is almost inconceivable that NB-IoT will ever become as power-efficient as Sigfox. This huge difference will dictate the use cases for the networks. For example, for sensors that can be operated using mains power, NB-IoT becomes more logical. However, for the majority of sensors, that is, the ones that use battery power, Sigfox will almost always be the best option.


Unparalleled Coverage, Capacity and Quality

Sigfox is the largest IoT network in the world, in terms of coverage, by quite a large margin. In Ireland, VT IoT operates over 150 sites and provides over 97% outdoor population coverage. Now, let’s take a step back and put this into perspective for you. Vodafone, Ireland’s largest mobile network, operates well over 1,000 cell sites and claims 96% 4G population coverage. Yes, you read that right, Vodafone easily has over ten times more sites than VT IoT. The company plans to add an additional 120 base stations to their existing network, bringing indoor population coverage to 97% and the total number of base stations to 270. VT IoT plans to expand its portfolio of base stations to achieve better indoor and underground coverage, which requires a greater densification of base stations. Shown below is a coverage map of VT IoT’s coverage in Ireland.

The reason VT IoT is able to provide such a large coverage footprint with so little base stations is the physics of ultra-narrowband modulation which can travel over exceptionally long distances. Not only does the Sigfox network travel over long distances, it will provide excellent indoor and underground coverage with improved densification, important for applications such as smart metres which are typically located underground. Each message is 100 Hz wide, Sigfox uses 192KHz of the available band.

Sigfox provides an excellent quality of service because of the way it is intrinsically designed. A sensor will produce three messages, all identical, on three different frequencies and at three different times (time and frequency diversity). Another feature of Sigfox which ensures a high quality of service is called spatial diversity. This essentially means that when a sensor emits a message, it will be received by at least one base station, usually three. NB-IoT works like traditional cellular networks, connecting to one base station at a time. This same feature means Sigfox is resilient to signal jammers, whereas NB-IoT would be rendered unusable if a jammer were to be present. This opens up more opportunities for using Sigfox, for example, an alarm system.

The IoT revolution will entail millions and billions of devices connecting to one network. Such a large number of independent connections will require a huge amount of capacity, the capacity that would simply be unimaginable to expect from today’s cellular networks. The huge capacity offered by the Sigfox network is a result of the ultra-narrowband modulation which is extremely spectrum efficient as the energy is concentrated into a very small bandwidth (several bytes). Something else to take into account, with Sigfox, capacity is not hindered by the quality of the available signal. So, the capacity does not deteriorate as the signal quality worsens, something that is not seen with traditional cellular networks.

As I’ve mentioned already, Sigfox is a global network for the Internet of Things. This means roaming is seamless, as the device will automatically detect and broadcast in the correct band when moving between continents. In fact, there are just four bands with Sigfox compared to eighteen with NB-IoT. This adds unnecessary complexity and fragmentation to NB-IoT.

Versatility Allows For More Use Cases

Like pretty much any other technology out there, Sigfox also has its limitations and drawbacks. These shortfalls will determine whether or not using the technology is viable on a case by case basis. Features such as a very low bitrate make providing OTA software updates to Sigfox sensors almost impossible. This is where versatility plays a major role in enhancing the core technology. Most Sigfox sensors utilise more than one means of connecting to the Internet, such as Bluetooth, WiFi, NFC or even NB-IoT.

Take for example a Sigfox smoke detector. Let’s pretend there is a major flaw that requires a software update to quash the bug. What do you do? It would be ridiculous to assume that the update could be deployed quickly over the air using Sigfox. It would be equally ridiculous for the manufacturer to have to visit the buildings where the smoke detectors are installed and update them on-site. In this scenario, WiFi, Bluetooth or NB-IoT would be excellent options to deliver the update. They are technologies proven to cater for high-bandwidth applications such as software updates. When the smoke detector receives a message from a Sigfox base station to temporarily activate WiFi, Bluetooth or NB-IoT to allow the update to be carried out, it saves time and energy.

This same versatility also applies to other applications such as the aforementioned bag trackers. Everyone knows that GPS is a very precise method for geolocation, however, that precision collapses when we move indoors. So what happens then, we can’t track anything when it is under a roof? Of course not. Again, we can make use of WiFi to bolster Sigfox. The device can activate WiFi indoors and passively “sniff” the SSID’s which are available without ever having to connect to them. This data can then be compared with a database of recorded WiFi SSID’s and their unique location to determine where exactly the device is. It won’t be as accurate as GPS, but it’s surely better than nothing. Even the base stations that provide coverage feature a form of versatility. If there is no fixed backhaul, 3G or 4G may be utilised instead.

The point that I’m trying to make when I explain the versatility available with Sigfox is that it drastically widens the applications of the technology. Technologies work best when they are complemented by one another, limiting the drawbacks of each individual solution.

Conclusion: Unlocking the Potential of the IoT Revolution

Sigfox is a global network built for the Internet of Things, built to connect millions of devices to one network. It is vastly different from traditional cellular networks, and that’s where its biggest advantages come from. As we connect more and more devices to the Internet, we will need a network that is able to meet the demands of all these devices. Whether the telecom juggernauts would like to admit it or not, Sigfox is a promising technology, a technology with the power to change the world.

By no means is this a puff piece about Sigfox, it serves a purpose to illustrate that there is a brighter future ahead of us when everything is connected to the Internet of Things, Sigfox is just one method of fulfilling this future. There will be cases where using Sigfox is simply not feasible, the features will determine the applications of the technology. Likewise, NB-IoT is an equally promising technology with its own set of benefits and use cases which I intend to explain further in a later article.

With over 97% outdoor population coverage on VT IoT’s network, Sigfox currently holds a major coverage advantage over any other IoT network in Ireland. That same advantage persists with cost and power consumption, both of which trump that of today’s NB-IoT networks. The global scale of the Sigfox network is a key benefit, along with the unparalleled coverage, capacity and quality that the network provides. The versatility and complementary nature of Sigfox allows the technology to cast a wider net over the number of applications.

The great news is that Sigfox and NB-IoT co-exist in Ireland, and both technologies push the IoT industry forward. Because at the end of the day, while these networks are similar in terms of their fundamental purpose, they were designed for different use cases.

1 Comment
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