Understand the main differences between LPWAN technologies used in IoT. This article investigates three main networks, namely LoRa, Sigfox, and NB-IoT.
The Internet of Things is a network of interconnected digital endpoints such as connected devices, networks, servers, IoT applications, etc., all communicating. As stated in our article about what is IoT, the 'things' that makeup IoT systems all share a common trait - they are IoT devices with the ability to transfer sensor data over a network to the internet.
Sigfox, LoRa, and NB-IoT (Narrowband IoT) are low-power, wide-area network (LPWAN) technologies. LoRa and Sigfox fall under non-cellular IoT technologies, while NB-IoT falls under the cellular IoT category. Articles often pit them against one another in a race to the top. They have their strengths and weaknesses but play a role in the IoT space depending on the use case. Understanding the features and differences of each is critical.
The main challenge within the IoT world remains that of connectivity, particularly for industrial and commercial enterprises located within complex or remote locations, where traditional connectivity is not a feasible solution in terms of cost, coverage, and power requirements necessary for IoT applications. Bluetooth is designed for short-range applications, while cellular mobile connectivity and WiFi are prohibitive in charge and power demand for large battery-powered IoT sensors.
What is LPWAN, we hear you asking.
Low-power WAN (LPWAN) is a wireless wide area network technology that interconnects low-bandwidth, battery-powered devices with low bit rates over long ranges. LPWAN does not consist of one single technology but a group of low-power, wide-area network technologies in many shapes and forms. LPWANs can use licensed or unlicensed frequencies and include proprietary or open standard options. LPWAN is for sensors and applications required to send small amounts of data over long distances, from varying environments, and only a few times a day.
Created for machine-to-machine (M2M) and internet of things (IoT) networks, LPWANs operate at a lower cost with greater power efficiency than traditional mobile networks. LPWANs can also support a more significant number of devices over a wide-ranging area. The catch here is that the data sent from devices using LPWANs is less complex than that, necessitating high-speed cellular networks used by our mobile devices (think images and videos shared on your smart device).
LPWANs are best suited for applications that require infrequent up-link delivery of small messages (think a small text SMS on your old Nokia 3310). This technology also means cheaper IoT device components, resulting in a lower overall price. It also means a longer battery life, sometimes running into years. Sigfox or LoRa networks have separate base stations from cellular base stations and also from each other.
That is why choosing an LPWAN depends on the type of application that requires it. The choice must consider the desired speed, data amounts, and area covered. We use LPWANs in smart meters, smart lighting, asset tracking, precision agriculture, energy management, and industrial IoT enterprise.
The way LPWAN varies from high-speed cellular connectivity is simple - data rates are much lower, the devices consume much less energy to communicate over a network, and the pricing to communicate is mostly cheaper. For example, you pay a 20 euro connection fee per month for a sim card. With NB-IoT, you might pay 2 euros per year. With LPWAN, there isn't much information passing through, just small messages, hence the reduced price.
Energy is also an issue. Mobile phone batteries will run down on standby mode within a few days as the network communication technology consumes substantial battery life even when your mobile is not doing heavy tasks. Devices communicating on LPWAN and running on battery will stay alive for five years or more. If less communication is used, a device would survive on battery even longer.
Sigfox LoRa NbioT - what are they?
There are various networks globally, like WiFi, Bluetooth, wired Ethernet, 4G, 5G, etc. These networks send a lot of data over the internet, consuming considerable amounts of current and necessitating constant connectivity to a power source. The difference with WiFi is that this is limited in transmitting distance, whereas LPWAN can transmit up to long distances. High speed cellular networks are wider area networks, but not low power. LPWAN networks are wider area networks and low energy.
Sigfox, LoRa, and NB-IoT, along with others such as Mioty and Wirepas, are networks that transmit information from the devices to the internet but do not have a high data rate, and so do not consume much energy. They are networks by which a device 'speaks' to the internet and devices located at distances, some up to five kilometres away. In addition, often, the networks do not need a power source. Instead, a simple battery is sufficient and will last for several years.
These technologies all have one thing in common - they require their connectivity system, separate base stations, and network antennas. There are cellular and non-cellular technologies for transmissions. NB-IoT and LTE-M (a low power wide area LPWA technology standard), for example, are cellular technologies – they use the network used for mobile communication which is typically already deployed. Existing networks typically require only a software update.
Cellular technologies transmit on frequencies against a charge, and persons cannot randomly decide to transmit on these frequencies. To communicate on, say, 810Mhz, for example, you need to pay (service providers need to buy licenses to be able to use specific frequencies). With cellular technology come higher prices, by which you will expect a better quality of service, such as control signals sent at the same time. This quality is not necessarily available on frequencies that are free of charge.
Non-cellular technologies are networks constructed separately from cellular technologies. Sigfox and LoRa fall into this category. LoRa was the first to provide services in 2009, with Sigfox following in 2010. We at IoT Solutions Ltd brought Sigfox to Malta in 2016/17, ensuring it was one of the first countries that provided a nationwide Sigfox network. With Sigfox and LoRa, each country has frequencies where everyone can transmit, subject to limits per hour but free of charge.
The interesting thing about NB-IoT is that it uses the same antennae and base stations used by 4G and 5G to transmit both slow and fast data rates. So basically, it uses the same antenna mobile phones use. In contrast, Sigfox and LoRa can only transmit slow data rates; however, their base stations are significantly cheaper than NB-IoT and 4g, although not commonly found.
Here in Malta, we have the Malta Communications Authority (MCA), which is the entity that regulates the use of frequencies, and operators pay for licenses. We already had around 500 base stations for 4G for mobile phones. With a software update, some of these base stations would be ready to communicate with NB-IoT.
Here is an easy guide on the advantages and disadvantages of all three:
Sigfox can be considered the most basic one of the networks mentioned in this article. It has the lowest cost radio devices.
The radio protocol does not require two way-communication to communicate with the network, which makes the technology more effective and efficient for applications that are not safety-critical.
Sigfox technology bases its reliability on the repetition of signals from multiple base stations, which, if designed correctly, professionals argue may be more reliable than the two-way communication required in cellular networks but more efficient.
Sigfox boasts the most extended signal range of all three technologies.
Sigfox is one company that has a common network service, therefore roaming between countries is much more straightforward.
Sigfox requires the network constructed from the ground up, unlike cellular technology, which is a firmware upgrade for some of the base stations that have the hardware capability.
The radio protocol is also operating in an unlicensed spectrum which might not make it ideal for specific applications which require to have control over the radio spectrum used.
There is no two-way communication, meaning that messages are not acknowledged.
Sigfox is the definite winner for logistical applications and remarkably price-sensitive applications. Sigfox topology also offers seamless worldwide connectivity, making it the clear winner for logistics applications.
LoRa is the best when it comes to low power consumption when compared to competing technologies. LoRa enables smaller devices which are sometimes critical for specific IoT applications.
LoRa also allows anyone to set up their Private Network.
Nationwide networks, if available, are not necessarily covered by the quality of service SLA, possibly limiting nationwide applications of the LoRa technology.
Roaming between different LoRa networks may be complex due to different network server providers, limiting mostly logistics applications or similar.
LoRa has the weakest signal range when compared to the other technologies.
The LoRa ecosystem is arguably the richest. LoRa (Long Range) is a patented digital wireless data communication IoT technology developed by Cycleo of Grenoble, France. Semtech acquired it in 2012, which holds the IP for LoRa transmission methodology.
LoRa doesn't have a nationwide network in Malta yet, whereas countries such as France and Spain have a LoRa nationwide network. In Malta, LoRa networks are still sporadic, according to projects that need LoRa connectivity.
NB-IoT (Narrowband IoT)
NB-IoT makes use of existing infrastructure, which makes it easiest to deploy and maintain
NB-IoT is governed by companies that have all been in the telecommunication industry for a very long time.
NB-IoT allows for two-way communication, which makes it ideal for certain applications that cannot afford to miss a message, even later ones.
NB-IoT does not yet allow for worldwide mobility, limiting the applications that can use NB-IoT.
Rather than roaming assets, NB-IoT best suits primarily static assets, like meters and sensors in a fixed location.
NB-IoT if you want to increase the density of the network it is much more complicated and costly since the base station is more expensive.
NB-IoT is for simple devices that need to connect to an operator network via a licensed spectrum. The key acronym here is NB - Narrow-Band. Typically, Narrow-Band is implemented in telecommunication technologies to transmit data on some frequency sets. NB-IoT is the "clean sheet" initiative by the Third Generation Partnership Project (3GPP), the organization behind the standardization of cellular systems, to address the needs of low data rate devices that need to connect to mobile networks often powered by batteries.
Because NB-IoT is a cellular-grade wireless technology that uses OFDM modulation, the chips are more complex. NB-IoT is not an IP-based communication protocol. It is for simple IoT applications, meant to send and receive small amounts of data, and designed for more infrequent communication purposes.
It is message-based, similar to Sigfox and LoRa, but with a much faster modulation rate that can handle more data than those technologies. You can't connect to an IP network and expect to use it as you would with a smartphone.
Which one fits your needs?
As in everything in life, all these options have advantages and disadvantages. The first thing you need is a clear understanding of what you need from the application, and what type of information you need to get through. It would be best to consider a few things when choosing which network best suits your needs.
First and foremost, you need to ask if either one of these providers already has a network in the area you are / or wish to operate. A successful network deployment depends on the operator and whether that particular network is available in your country.
LoRa is the most flexible. Either an operator gives you the network in that country, or you can buy your base station from the internet. Follow some guidelines, mount it, and create your own LoRa network, just like you would purchase and mount your WiFi router (although the latter is more expensive). With LoRa, you can add more information, and the data rate is faster.
Although they all have low data rates, some are lower than others. Sigfox is the network with the least data rate, with each message topping at 24 bytes. NB-IoT can get through much more information averaging 512 bytes. That is 20 times as much as Sigfox.
A safety button that requires that each message is acknowledged and confirmed would be well catered for by both LoRa and LTE-M but not for Sigfox, since with the latter you won't know if the message has arrived (lacks two-way communication). In the case of water meter measurements, though, or anything sending less information and less frequently, Sigfox is a good solution.
In terms of distance, Sigfox has more extended range capabilities. Suppose a device needs to transmit as well as receive data. In that case, Sigfox is not the solution for you because Sigfox can send but not receive back much information while the rest allow for a substantial amount of to and fro data.
Consideration also needs to be given budget-wise. NB-IoT prices have dropped considerably, while others can offer services as low as 1 euro per year. As for Sigfox, prices vary between 1-2 up to 7-8 euros per year, depending on how many devices you have.
Anyone considering this service needs to understand that every application has its strengths and weaknesses. It is essential to evaluate what the client wants to achieve and then decide on the best solution according to those considerations. It is in these cases that consultation with companies with years of experience, as in our case, helps a client make the right decision for its business needs.