Reliable M2M connectivity for the Internet of Things: National roaming for IoT devices

Always on the move with the best local network, no matter where. This is not wishful thinking, which is precisely why our M2M SIM cards exist. Our SIMs use the mobile networks of different network operators in one country via national roaming. So they offer stable and secure M2M connectivity for IoT devices almost everywhere.

The Internet of Things: Devices networked everywhere via mobile communications

The Internet of Things (IoT) is growing. Every day, more IoT devices and objects are connected to each other and the information associated with them is made available in a network as part of M2M communication. But in order for the data collected by IoT devices to be processed in a network in the first place, it has to get into that network.

This is where mobile communications and our M2M SIM cards come into play. Because: collected data can be transmitted quickly and securely from any IoT device via mobile radio. Mobile radio is established and standardised as a technology, and the infrastructure is available almost everywhere. And not only in Germany, but worldwide. That's why mobile radio is very often used for M2M communication. The sticking point here is that nationwide availability, especially in Germany, is not achieved by a single network operator, but only by the mobile networks of all network operators together.

No network provider offers nationwide network coverage

According to the Federal Network Agency (post retrieved on 28.10.2021), there is a lot of catching up to do in terms of network coverage by individual network operators: about 7.2 per cent of Germany as a whole is considered a "grey area". There, only one of the mobile phone networks of the major network operators is available in the 4G standard, which increases the risk of connection interruptions and failures. In individual federal states, such as Bavaria, the situation is even worse: There, the network of one mobile network operator at most is available on 15.5 percent of the total area.

This patchy coverage shows the relevance of using appropriate M2M SIM cards for IoT and M2M projects.

National roaming for maximum network coverage

An M2M SIM card - unlike the SIM card from a private smartphone - can also use the networks of different network operators within a country. This is called national roaming. M2M SIM cards are therefore also called roaming SIM cards or multi-network SIMs. National roaming is possible because we, as providers of M2M SIM cards, have concluded roaming agreements with different network operators. These agreements allow our M2M SIMs to connect to the networks of our contractual partners.


Steered vs. non-steered roaming

Not all national roaming is the same. There is a small but subtle distinction here that is very important for IoT and M2M projects. We are talking about steered roaming and non-steered roaming.

With our SIM cards, it is not the network operator that counts, but exclusively the strength of the available mobile network at a location. This is important because the availability of a mobile network varies depending on the location: sometimes the network of one provider is strongest, sometimes that of another provider. If a provider issues M2M SIM cards itself, these are usually based on the network provider, not on the network strength. In concrete terms, this means that if provider V issues a SIM, it will always try to connect to provider V's network first - regardless of how poor the connection in its network is at the moment. Only when V no longer offers a network may the IoT device log on to another mobile network.

Since only the strength of the available mobile network at the respective location counts for our SIM, devices are allowed to switch networks as soon as another provider offers a better connection than V. The ability to choose or use the network completely independently of the provider is called non-steered roaming or network independence.

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