The Internet of Things (IoT) is a growing paradigm that connects various devices or things – including sensors, software, electronics and other physical objects – in order to collect, exchange and process data.
New innovative networking solutions are emerging which would make IoT a reachable reality, but which one to choose?
IoT is finally starting to get the traction that has long been foretold; the famous 20 Billion connected devices number by 2020 is slowly starting to become reality. However, most of these devices will not be connected to a home WIFI nor to a smartphone; they will mostly exist on a parallel plane, mostly invisible to end-users.
When the average person thinks of IoT, they usually think of home appliances with dumb connectivity, or wearable devices that rely on a smartphone to deliver any usable functionality. The IoT ecosystem has so much to offer once it escapes the WIFI and mobile connectivity restrictions.
Transportation, manufacturing, asset-management and infrastructure-monitoring are only a few verticals that will see massive enhancement due to the pervasive nature of IoT.
The innovation in this field does not originate solely from new technology but mostly from adapting old technologies to the requirements of IoT and making old innovations cheap, available and reliable.
LPWAN: And old paradigm put to good use
Low-Power Wide-Area Network (LPWAN) is a type of wireless communication network that is designed for wide-range communications but can only handle a very low data rates. These networks suit perfectly the IoT use case, where connected objects send small amounts of sensor-generated data and operate on battery power.
SigFox
SigFox is a French company that aims at becoming the first global IoT networking provider. It positions itself as an IoT network provider. Devices send their data through the network, SigFox handles the transfer of the messages through a HTTP callback to a pre-configured backend.
SigFox: Radio properties SigFox is an ultra-narrowband technology that runs on sub-GHz frequencies on industrial, scientific, and medical (ISM) radio bands: 868MHz in Europe/ETSI and 902MHz in the US/FCC.
SigFox: Coverage and infrastructure
As of 2016, the SigFox network covers 23 countries and over 1.3 million km². The company deploys its antennas with the help of local telcos around the world. This means that you don’t have to worry about setting-up the infrastructure.
SigFox: Constraints and API
SigFox enforces a number of constraints on the messages transferred over the network where each device can send only 140 messages per day with a limit of 7 messages every hour. Each message can be up to 12 bytes long.
The radio modules are also able to receive 4 incoming transmissions per day.
The network is subject to these constraints because endpoints are designed to be transmitters and their reception sensitivity is not optimal.
SigFox fully manages the communication between the IoT device and the application backend, which makes the integration of the radio module a fairly simple process for developers. To interact with the radio module one single API is provided, no configuration is required.
Device <---> Antennas <---> SigFox Cloud <---> Your backendThe SigFox approach is to give you one straightforward way to integrate the network into your product with known constraints, which makes the design process of the product as simple as it can be.
To start integrating SigFox you will need to buy a compatible radio module as well as a renewable subscription plan for your device.
LoRa / LoRaWAN
LoRa is a proprietary long-range wireless technology standard that operates on the Industrial, Scientific and Medical (ISM) band radio frequency spectrum (863 to 870 MHz in EU / 902 to 928 MHz in US). It is a PHYsical layer (OSI Layer 1) protocol that offers a long range and low-power communication medium for machine-to-machine (M2M) and IoT applications [source].
LoRa technology was originally developed by Semtech , but it is now managed by the “LoRa Alliance”. Any hardware manufacturer can build LoRa modules but has to get a certification of compliance from the alliance.
However, (as far as I can tell) radio modules are exclusively produced by Semtech for the time being.
LoRaWAN has been defined as a data-link (MAC) layer (OSI Layer 2), with some elements of a network layer (OSI Layer 3) on top of LoRa (What is LoRaWAN).
LoRa vs. LoRaWAN
LoRaWAN is an open protocol built on top of LoRa.
While LoRa offers simple point-to-point message delivery, LoRaWAN protocol manages devices’ communication with the application’s backend and provides an end-to-end encryption and authentication scheme.
As they are more complex and offer considerably more functionalities, LoRaWAN chips are more expensive than LoRa chips.
LoRa / LoRaWAN: Coverage and infrastructure
Contrary to SigFox, the LoRa Alliance does not wish to position itself as a network provider. Its goal is to develop a standard and sell chips. This means that there is no single monopole on the LoRa network.
If you want to use LoRa for your product, you have two options:
1- Deploy your own network
You can buy chips and create your own network of devices, gateways and backends.
Also, you will have to deploy and maintain both the gateways and the devices, but you will have full control over your network and you can adapt, tweak and modify it as your product grows and its needs change.
2- Use a network operator
Several operators are starting to offer LoRaWAN networks (Orange) in certain areas. You can buy connectivity plans from them. This will relieve you from the burden of managing and maintaining an infrastructure but will put you at a risk of an operator terminating its LoRa offering after a few years.
LoRa: Constraints and API
Unlike SigFox, LoRa modules allow for granular configuration and set-up. This means that if two devices are not configured exactly the same, they will have a hard time talking to each other. This makes the setup process more prone to errors but gives you more control over your device’s energy consumption.
SigFox vs. LoRa : Side-by-side
Even though both networks position themselves similarly in the IoT market, they have significant technological and marketing differences. While SigFox aims to become a global IoT operator, LoRa alliance wants to provide a technology that allows other companies to enable a global IoT.
SIGFOX LORA Frequency band 868/902 MHz (ISM) 433/868/780/915 MHz (ISM) Urban range 3-10km 2-5km Rural range 30-50km 15-20km Packet size 12 bytes Defined by user Devices per access point 1M 100k Status In deployment Spec released June 2015
| SIGFOX | LORA | |
|---|---|---|
| Frequency band | 868/902 MHz (ISM) | 433/868/780/915 MHz (ISM) |
| Urban range | 3-10km | 2-5km |
| Rural range | 30-50km | 15-20km |
| Packet size | 12 bytes | Defined by user |
| Devices / access point | 1M | 100k |
| Status | In deployment | Spec released June 2015 |
| Topology | Star | Star |
Unlike SigFox, standard LoRa modules can operate in a bidirectional way. Using the same radio module, a receiver can be transformed into a transmitter at any given moment and vice versa.
Therefore, LoRa is more adapted to command-and-control scenarios.
On one hand, SigFox offers a very simple API to integrate the radio module. On the other hand, LoRa offers a highly configurable low-level API, which makes different optimizations possible. The tradeoff is that this makes the integration of the LoRa radio module more complicated than SigFox.
SigFox messages are limited by design to 12 bytes. For LoRa, message length is defined by the user. To ensure compliance with regulations, developers must ensure that radio messages would not last longer than five seconds over the air.
Both technologies offer some security functions. However, only SigFox identifies and authenticates devices.
Both networks provide high resistance to communication jamming because transmissions are achieved through one-sided communications without any network authorization.
Neither SigFox nor LoRa offer encrypted communications [source]. LoRaWAN offers end-to-end encryption and authentication, but it still has many problems with moving devices and complicated scenarios.
Specific scenarios
Q: I am building a connected city infrastructure (e.g. SmartGrid, water-management, pollution sensors), what network should I use?
A: LoRa / LoRaWAN : If your deployment is limited to a geographic location and your IoT sensors won’t be moving that much, LoRa makes more sense for you.
Q: I make bikes. Now I want to make connected bikes, what network should I use?
A: SigFox : Tell your users that their connected bikes will only work in certain countries and put SigFox modules in your bikes. SigFox offers more ubiquitous connectivity.
Q: I sell connected home appliances, what network should I use?
A: You should stick to WIFI for now, if you’re selling a connected door lock take advantage of the fact that it will be installed in house. You can always offer an option that has SigFox/LoRa as a fallback solution when the WIFI is down.
Q: What if I have a LoRaWAN contract with provider A, but my device has moved to a location covered only by provider B.
A: For now, too bad for you. Your device can’t connect if provider B, does not allow it. However, the LoRa Alliance is already thinking about roaming and the possibility to route your device transmissions through another provider.
SigFox and LoRa are both good steps towards a more mature and ubiquitous IoT. Both offer a networking solution that fits certain use-cases and it is up to you to figure out which one suits you best.
Other alternatives are on the market all fighting for a growing market share. We can list Neul, 6LowPAN, Thread, NB-IoT, etc. But during my Master’s internship in SAP Labs, I have worked extensively with the SigFox and LoRa protocols especially their (lack-of) security features, where I have worked on IoT-specific end-to-end encryption.