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How to maximise global coverage for IoT devices.

Reliable global connectivity is hugely important for many IoT use cases. Here are some tips on how to achieve it.
Maximising Global Cellular Coverage HEADER

We recently conducted a poll on LinkedIn asking our followers about the hottest IoT question they have right now.


The most popular topic was maximising global coverage.*


*by a slim margin and is not statistically significant with a population of 45 and being online. But you know that :)


So I’ve written this brief article to offer some tips on how to maximise global coverage from the perspective of cellular connectivity. 


I’ll cover what we know at Onomondo and steer well clear of the hard hardware stuff like antennas.


Let’s get into it!


Work with a partner who has many networks


This is a bit of a no-brainer. The more networks your SIM can access around the globe the better the coverage will generally be.


There are some points to consider here nevertheless as not all operators are created the same.




Depending on whether you go with an MNO, MVNO or Full MVNO, you will get different levels of coverage and insights into what's happening with your data.


  • MNO (Mobile Network Operator) - MNOs own the RAN infrastructure, such as the base stations. Vodafone, T-Mobile, Orange, TDC, and China Mobile are examples of MNOs.
  • MVNO (Mobile Virtual Network Operator) - MVNOs lease access to their infrastructure to MVNOs.
  • Full MVNO - Some MVNOs are just resellers of SIMs from MNOs. Others integrate their own core network into the MNOs radio access technology and have complete insights into data passing through the network.


MNO vs Full MVNO

The difference between a MVNO Reseller and Full MVNO is quite substantial.


True global connectivity


Although some MNOs are big (Vodafone operates in 21 countries for example), some MVNOs make agreements with multiple MNOs and have even better coverage.


There are a few Full MVNOs out there that have made deep integrations with one or more MNOs. But none have gone as far as Onomondo and created a truly global network.


At Onomondo, we’ve integrated our core with all 700+ networks in our global footprint.


This gives users real-time insights in every network their devices attach too. It lets users avoid the problem of permanent roaming restrictions, where devices get banned from the network after roaming in a network for over e.g. 45 days (Read more: IoT's struggle with Permanent Roaming and potential solutions). And it means we can give immediate and itemised billing information as we aren’t reliant on a third party to understand what's happening in the network.


Use multiple networks per country


You’ve probably experienced it on your cell phone. You’re travelling in the countryside and you’ve lost reception or you’re stuck on two bar 3G. But your partner, on the other hand, is happily streaming Netflix on 4G in the same location.


The issue of differing coverage quality in localised spaces is exactly the same for IoT devices as well. Operators place their antennas and technologies (3G, 4G etc.) in the places where they think it will have the most impact. The system works really well, until it doesn’t.


One of our devs created this nifty site which illustrates coverage and the available technologies throughout Denmark really well:


telemaster shows you where all of the cell towers in Denmark are.


The solution is quite clear, to maximize coverage you want your device/phone to be able to automatically access the network with the best coverage in a given location. So for IoT devices, you want to have access to all the networks in a country to be able to maximize coverage. 


Why just give your device access to TDC in Denmark when it can have more reliable coverage when it can access Telenor and 3 as well?


At Onomondo, we make it possible to select the networks your device can connect to via network whitelists. This means you can add or remove any of our 700+ networks to your SIMs personalised coverage map. It’s entirely up to you and all of this is available via our API as well, of course.


Network selection

Onomondo makes it easy for users to define which networks devices can connect to.


Network selection as described above is quite unique to Onomondo because of how we’ve set up our network. Others can’t offer this in the same way as they don’t have the breadth of RAN integration that we have achieved (we were the only ones with a CTO stubborn enough to do it).


This ties into a key factor in automatic network selection: you need to make sure your SIM doesn’t have a PLMN list on it.


Don’t use PLMN lists


SIM cards usually have a Public Land Mobile Network (PLMN) list on them. The PLMN list tells the SIM which networks it can attach to in a prioritised order.


The list is helpful for traveling with your phone. Your MNO will use the PLMN list to define the set of networks your phone can roam on while overseas.


But PLMN lists aren’t smart. Thanks to the PLMN list, your device could prioritise networks with weak signals over networks with strong signals.


Fortunately, it’s possible to leave them blank. In this scenario, the radio module will attach to a strong enough network (also called -85 dBm) and not continually try to connect to a prioritised weak network.


Not having a PLMN list also means that the strategy of having multiple networks per country is optimised. Now your device has multiple networks to choose from in a location and will choose the strongest (or first strong enough one it finds) by default.


You can read more about PLMN lists here: PLMN: Improve coverage with automatic network selection


eUICC isn’t ideal for maximising coverage


eUICC is a great way to avoid permanent roaming issues. Loading multiple operator profiles onto your SIM is one way to avoid permanent roaming bans.


But make sure you take a look at the settings. It’s likely you only have one operator added per country and will not benefit from having access to multiple operators in any given country.


Additionally, eUICC software comes with a form of vendor lock-in. If your eUICC vendor suddenly isn’t suitable for the coverage you need (e.g. due to technology limitations), you do not have the freedom to leave that would keep your devices future-proofed.


New IoT technologies


Traditional cellular technology wasn’t developed with IoT in mind. That means that IoT use cases like smart meters, indoor air-quality sensors, and leak detection sensors can struggle to get coverage indoors. 


Fortunately, new cellular technologies developed for IoT have been developed. NB-IoT and LTE-M are Low Power Wide Area Networks (LPWAN) that are available right now.


These new forms of connectivity are still in their early stages (NB-IoT still needs to have wholesale roaming agreements for example), but already provide massive benefits for devices that need to use a low amount of power, come in smaller form factors, need to be cheap, and require deep penetration.


There is debate on which of the two technologies is best. At the end of the day, it depends on your use case, but in general, we’d say that LTE-M has a lot more flexibility and has the same strengths as NB-IoT. You can read a full analysis here: NB-IoT vs LTE-M: A comparison of the two IoT technology standards.


If you can’t decide between technologies, why not use multiple?


Fallback technologies

Going back to our early discussion on having multiple networks in each country. It also makes sense to choose a modem with multiple technology options available.


You can see in, for example, that each base station has varying technologies available.  


telemaster shows you the specific cellular technologies available on each antenna.


So look for modems with e.g. 2G, 3G, or 4G fallback. You’ll lessen your chances of losing coverage and have the best possible chance of your devices not going dark.


Keep asking questions


There are no dumb questions in IoT. It’s quite a broad field with a lot of new ideas being added every month. That means it’s unfortunately quite common for IoT projects to fail. What works in PoC will often struggle or fall flat in production due to some considerations about global connectivity being missed.


All we can say is that it’s important to keep asking your potential connectivity provider challenging questions and to think big.


This podcast on scaling IoT globally is a good next step in researching coverage issues.


IFA Scaling Cellular Connectivity

Henrik, CTO at Onomondo, and Anders, CCO at Onomondo, talk about what it takes to build a global cellular network on the IoT For All podcast.


Otherwise, contact us with any questions you may have


We might even have some good questions for you to challenge other cellular connectivity providers to help your IoT solution scale seamlessly and enjoy maximum possible coverage.