French M2M and IoT network provider Sigfox has partnered with Securitas Direct and Abertis Telecom in Spain to link millions of home and premises security alarms. The group says is one of the largest deployments of devices on the IoT. The deal will see the Securitas alarms connected to and monitored by the Sigfox cloud platform, with connectivity provided by Abertis’ network of dedicated Sigfox cell towers.
The Sigfox network has been built to carry two-way communications consisting of small messages i.e. the archetypal IoT transmission, which Sigfox says eliminates the cost and energy-usage barriers to IoT implementation – key to achieving mass deployments of low-power devices. We spoke to Sigfox’s Head of Communication, Thomas Nicholls, to learn more about the technology behind the Sigfox platform.
The global Sigfox network has been deployed on the back of the Sigfox Network Operator partnership program, and covers 1 million km2 so far. Abertis itself has also begun deploying a smart city network in Spain, which will carry communications between deployed devices and centralized management systems, in a very similar vein as the Arqiva network that has begun construction in the UK.
Arqiva already manages and owns much of the infrastructure behind the UK’s terrestrial television broadcasts and a network of WiFi hotspots, so the process of adding Sigfox compatibility would have been fairly straightforward. The deal will see Arqiva to connect 10 million smart meters to its own network, as part of a government program to improve energy efficiency, with the potential to convert the meters to the Sigfox protocol in later phases. The Arqiva network will initially cover 10 cities before expanding to reach 100% coverage, as Sigfox has managed to secure in Spain, France and the Netherlands.
The Securitas alarms will not be using the Sigfox network as their primary method of communication, but as a backup instead, should a physical phone line be cut or a cellular connection fail. The company claims to be the leading supplier of home and business alarms in both Spain and Europe, and uses a monitoring center in Norway to handle its network of alarms. Operating in 13 countries (Belgium, Brazil, Chile, Denmark, Finland, France, Italy, the Netherlands, Norway, Peru, Portugal, Spain, Sweden), the company has 1.6 million clients globally, and 700,000 in Spain alone. It managed to add Sigfox compatibility to its deployed alarms with a firmware update – hinting at the massive potential for retrofitting existing products with Sigfox connectivity.
Sigfox uses a set of patented ultra-narrowband (UNB) technologies for its network. In Europe, Sigfox uses the 868MHz ISM band, and in the US it uses the 902-928MHz ISM band – which is a reserved portion of the RF spectrum that is available worldwide.
The major benefit of these signal frequencies is their long attenuation, meaning that the radio waves will travel much further and through more barriers than radio waves from further up the spectrum – such as those used in WiFi (2.4GHz – 5GHz). This is key to the mass deployments that the IoT envisions, with devices needing the same level of connectivity in underground installation as they do when outside. Given that many devices are not mobile and are installed in one place for the duration of their lives, it is vital that they can connect to the wider internet without fault. Lower attenuation gives you a longer range and better penetration, at lower power levels.
Sigfox’s maximum data rates are currently 100 bits/second in Europe (ETSI) and 600 bits/second in the US (FCC) – thousands of times slower than WiFi. But the power savings are hugely significant. Sending data at a higher rate requires more power. So the lower data rate inherently allows devices to get more out of their battery capacities.
The Sigfox chips use around 25 milliwatts for one-way communication, with two-way requiring slightly more. So while you won’t be able to hold a voice conversation or stream video on a network like Sigfox’s, that very low data-rate means you can install devices that can report status updates and reports for years on a single coin-cell battery, or longer thanks to energy harvesting technology or wireless power.
Sigfox doesn’t require dedicated hardware for devices to communicate on its network. Nicholls said that the same chips that are currently installed in devices like garage door openers are perfectly capable of talking to the Sigfox base stations. All that is requires is the Sigfox software protocol, which the company gives to developers royalty-free. Sigfox is simply a software protocol at the device-level, compatible with any sub-1GHz device.
The network architecture itself is a collaborative network system, which means that each cell has no knowledge of other cells that may be nearby. This allows quick rollouts, as adding a new cell to an area does not require you to reconfigure all the other nearby cells.
Nicholls added that if the network became congested in a specific area, the upgrade would be a simple matter of adding more cells where needed and shortening the range of the existing cells. Each cell can handle around 1 million devices, and is comprised of an off the shelf antenna and a small server. Nicholls said the architecture was scalable, and able to handle billions of devices.
All the complexity is in the network, which helps Sigfox and its partners keep the hardware costs down. The software defined network (SDN) is configured by a centralized cloud, whose main task is to de-duplicate the multiple copies of data that might be collected by the independent cells in the collaborative network architecture.
But Nicholls stressed that the network’s main advantage arises from its simplicity. Unique ID numbers in each device mean that you don’t have to provision the devices as you would in a cellular network – activation is straightforward. The other main benefit is keeping the hardware and subscription costs down.
Avoiding cellular connectivity modules, which can range from around $15 for a 2G SIM module and up to $40 for an LTE equivalent, also avoids the expense associated with a cellular M2M subscription. Instead, Sigfox’s compatibility with cheaper chips means that it is several times cheap to ship at volume and keep online.
Sigfox is a company of around 60 employees, with plans to double that number within a year. As the network partners like Abertis and Sigfox handle the physical installation, the majority of Sigfox’s staff are tasked with monitoring its cloud platform and planning new installations. Nicholls said business was growing rapidly, with 70 leads in the previous month that would cater for over a million connected devices – with bookings to handle 5 million devices already on the cards.
The company hopes to go public, and has so far attracted $35 million in venture funding, largely from Intel and French venture funds. The platform appears to be much more flexible than a comparable cellular network, given that it managed to achieve 100% coverage in Spain using 1,500 base stations with a budget of $12.9 million. Its next targets are the US and Asia.