IoT and 2G / 3G / 4G networks
When it comes to machine-to-machine (M2M) and IoT devices, all mentioned network types are technically available and modems easily accessible. However, there are many things to consider when choosing the proper cellular network modem for your next project.
The first question to ask is: in which regions your devices will be used? Is there a full coverage of 2G / 3G / 4G?
There are several open source options (along with telecom coverage maps) for finding out the coverage of mentioned network types in different regions. One example would be OpenSignal application, which is described more thoroughly in article OpenSignal now features crowdsourced mobile coverage maps.
LTE / 4G has relatively good coverage in most parts of world, though it still needs some improvements here and there. Nevertheless, global operators are going for high speed data services, so odds are in favour of global LTE coverage sooner or later. More detailed information of 4G coverage can be found on OpenSignal The State of LTE, general network information from spectrummonitoring.com and worldtimezone.com.
Example of coverage in Germany, measured with crowdsourcing mechanism
2G and 3G networks on the other hand are subject to be shut down in upcoming years, meaning that IoT devices using such network modems might end up disconnected. In most cases, countries and regions have picked either 2G or 3G to be shut down, not both of them. The procedure itself will take about 1-2 years, requiring careful examination and support by the local mobile operators. Region wise, Europe is considering shutting down 3G before 2G (e.g. Telenor in Norway) when telecoms in USA are doing the opposite - shutting down only 2G network. However, Australia's telecoms will probably start shutting down both 2G and 3G quite soon.
The next question to ask from yourself would be: which cellular frequencies your modem needs to support? In other words, you need to identify the sets of frequency ranges within the ultra high frequency band that have been or needs to be assigned to your cellular modem.
In general, one needs to verify with 3 cellular network bandwidth groups: GSM frequency bands, UMTS frequency bands and LTE frequency bands. Frequency bands differ by country and the device engineer must make sure that bigger regions have similar frequency bands and work with specific modems.
Every country or region have their specific bandwidths available for all different network types. For example in Germany:
900, 1800 MHz
900, 1800 MHz
800, 1800, 2600 MHz
|Vodafone||900, 1800 MHz||2100 MHz||800, 2600 MHz|
Think carefully how much data does your device/application use in longer period of time and in high peaks.
- The safe bet would be to choose 4G/LTE modem, which has fallback for both of the oldernetworks - 2G and 3G. However, 4G/LTE modems cost more than 2G or 2G/3G modems, though the price has had a strong downward trend lately.
For some cases 2G/3G modem is more than enough, especially when devices need connectivity rarely or don’t send and receive much data. If you have made sure, that 2G or 3G will not be shut down in your target areas, then price-wise 2G/3G is definitely the option to go for.
In summary, when planning to launch your next cellular-based IoT device or application you would need to take into account the coverage of different network types, supported frequency bands and fallbacks from disabled networks.
The problem we are facing today in IoT fields is that mobile networks are not precisely optimized for very large amount of devices per small area. There are huge number of devices which use very small amount of data per month, for example 10KB or 1MB. For such devices and cases the telecom world is moving towards alternative network solutions - NB-IoT and LTE-M. NB-IoT is currently available in few countries in Europe (launched by Vodafone) and LTE-M was launched in USA by AT&T.
For M2M/IoT devices and vehicles, which use tens of gigabytes data per month or need to be connected to mobile networks in real time and 24/7, 5G network is being designed. 5G is huge step forward from 4G and its new developments (4.5G, 4.75G). The 5G network is expected to be launched by 2020. Let's see how that turns out!