NB-IoT vs Sigfox — Licensed vs unlicensed frequency spectrums
Sigfox
Sigfox currently provides a comprehensive broadcast and reception infrastructure in around 60 countries. Coverage varies, as some countries such as France or Denmark are almost completely covered, while in the USA, for example, it is still mainly limited to the metropolitan areas. Germany currently has coverage of around 85 percent. In addition, Sigfox covers almost all major airports worldwide, creating an advantage for logistics and tourism projects.
The French company’s technology limits the sensor device to 140 data transmissions per day and 12 bytes per message. This solution enables self-sufficient transmitters that can be used for several years on one battery. To do this, Sigfox uses an open standard that operates on sub-GHz frequency bands and can be used by any radio provider. The data is then sent to the Sigfox cloud, where the customer can collect it via an API. This makes Sigfox particularly suitable for logistics or smart city projects.
NB-IoT
The requirements for Narrowband IoT (NB-IoT) were defined at the beginning of 2016. This new narrowband radio technology provides a suitable LTE category for low-bandwidth IoT devices. NB-IoT leverages the existing infrastructure of LTE and GSM network providers to enable low-bandwidth communications for IoT devices.
As with Sigfox, the customer here can tap into existing infrastructure and does not have to build and maintain it cost-intensively itself. In exchange, the data is temporarily out of the customer’s control. LTE-M is part of Release 13 of the 3GPP standard, which is designed to reduce power consumption, lower equipment costs and enable deeper coverage. This is to reach challenging locations, such as deep inside buildings. This standard will improve NB-IoT in terms of bandwidth. In addition, this solution offers probably the highest level of security of the LPWAN technologies presented here.
Above all, the outlook for 5G promises interesting areas of application for NB-IoT in the IoT world, such as as a key technology for self-driving cars, thanks to its high potential in terms of range and data volume. The big question, however, is when 5G will become widespread and where NB-IoT will then be positioned in terms of price.
Key Features of NB-IoT
● It requires much less energy than conventional mobile devices such as smartphones or even cell phones. Battery runtimes of up to 10 years are possible.
● The overall costs are much lower than those of GSM, UMTS or LTE. An NB-IoT module currently costs less than $5.
● The data rate is limited, with a maximum of 250 kilobits per second (download and upload). NB-IoT is designed for the transmission of data and not for voice or SMS.
● About 100 times more devices can be networked per radio cell compared to GSM.
● The latency of NB-IoT is low: mobile technology is less suitable for transmitting real-time data or time-critical alarm messages.
● Compared to GSM, UMTS or even LTE, NB-IoT has much better building penetration and is still available in basements.
Licensed vs unlicensed frequency spectrums
In many other IoT applications, four properties are particularly important: low deployment and maintenance costs, low power consumption, reliable network coverage, and the ability to interconnect a large number of devices. So-called Low Power Wide Area Networks (LPWAN) fulfil these criteria very well. There are now a whole host of different LPWAN standards, some of which differ greatly from one another. The four most important at present are NB-IoT, LTE-M, Sigfox and LoRa. These technologies can be roughly divided into two groups: the licensed spectrum (LTE-M and NB-IoT) the unlicensed spectrum (LoRa and Sigfox).
Advantages of licensed mobile communication frequencies:
● Both NB-IoT and LTE-M can be built on top of the existing infrastructure and use the existing resources of the mobile network operators.
● Both mobile technologies are based on standards from the global standards body 3rd Generation Partnership Project (3GPP). 3GPP has introduced the standards for existing mobile communications technologies such as GSM, UMTS and LTE, as well as the new 5G. These standards, which are constantly being developed further, ensure that mobile communications technologies meet customer needs for international operation, stability, reliability, security, cost efficiency and high scalability.
● For NB-IoT and LTE-M, 3GPP standardization means that they will be available in the long term and that investments in these technologies are thus secured and not lost. NB-IoT and LTE-M are therefore fit for 5G.
● Another advantage of mobile networks is their interoperability: NB-IoT and LTE-M multimode radio modules can be switched to other carriers, including 2G and 3G. This means that these components also work in countries where mobile IoT networks are not yet available.
● NB-IoT and LTE-M benefit not only from the extensive support of mobile operators but also from a large ecosystem of chipset and device manufacturers. This ultimately reduces the risk of vendor lock-in.
Advantages of unlicensed frequency spectrums
The main advantage of Sigfox and LoRa is that they use free frequency bands for which no license fees are charged. SIM cards and contracts with mobile network providers are also not required, and roaming charges do not apply. The costs for operation are therefore lower overall. However, Sigfox and LoRa have other significant differences to NB-IoT and LTE-M, which may be beneficial or detrimental depending on your use case:
Sigfox in particular, but also LoRa, are designed to network very simple devices with each other. Therefore, they are often referred to as 0G networks Sigfox and LoRa require very little energy. However: for some IoT use cases, the data volumes may be too small, the transmission speed too slow, and the latency too high.
Both SigFox and LoRa have already been on the market for several years and are therefore field-proven. Nevertheless, the infrastructure at SigFox still has shortcomings. With LoRa, the user must take care of the network himself. However, companies in some countries are offering nationwide coverage with LoRaWAN networks. Setting up your own network can have its advantages. You can use it to cover an area that is not covered by mobile network providers. And: Within your own delimited network, the data remains in your own hands.
Unlicensed, proprietary spectrums require a large commitment:
SigFox is a proprietary technology developed by the French company of the same name and launched on the market in 2009. A non-profit organization called the LoRa Alliance is behind LoRa. But the technology is just as patented and proprietary because it only works with chips from the Chinese manufacturer Semtech. The users are therefore, dependent on the two companies as suppliers. If they want to switch to a different transmission technology, they also have to change their hardware.
