Nov 16, 2020

Why 2G fallback is still beneficial for LPWA 4G/5G based devices

Byline Igor Tovberg, Director, Product Marketing

In the past few years, there has been considerable mention of 5G and its ongoing deployment around the world. There is no doubt that 5G will deliver ground-breaking data communication speeds and low latencies that will allow many more applications to use wireless communications, whether they are fixed or mobile. It is easy to forget that much of the geographical deployment of 5G is initially focused on cities and densely populated urban areas. Even 4G, now in a relatively mature phase of operation throughout most European countries, Asia and North America, saw the infrastructure build-out from the densely populated areas. Travel through rural areas well away from the major cities, and you’ll most likely see 3G or HSDPA pops-up on your smartphone. While 2G is not often seen on our smartphone screen, in practice it has similar or better coverage than 3G in most remote location and most M2M devices are still riding the 2G network. It is believed that even when 3G is phased out, carriers will keep the legacy 2G network to keep supporting 2G M2M communication devices installed a long time ago.

The evolution and state of 2G networks

When the cellular infrastructure was in its infancy, delivering reliable voice communication was the priority. However, as wireless and embedded systems technologies have advanced, so has the potential to utilize the cellular network for data delivery in addition to its initial goal of voice communication. Technology revolutions such as the internet of things (IoT) have seen a significant rise from a diverse set of use cases, from utility metering through to logistics consignment tracking. For these and many other cellular-based applications, access to the network needs to be reliable and omnipresent.

Globally, the availability of a 2G network is mixed. For example, achieving this requirement within Europe still requires cellular wireless device to fallback for 2G.  In the United States of America, Japan and Korea, the 2G network has already been switched off. Across Europe, the deadline for switching off 2G services will be spread over a few years, although there has been an industry-wide belief that it may remain beyond 2025 in some countries.

2G network

2G delivers critical backup connectivity

The use of 2G networks is not disappearing as fast as initially thought, which assists in maintaining a network connection when 4G coverage is not available. This is the case in India, for example, where in some locations there is no reliable 4G coverage outside urban areas. The same is true for most of South America, and in Africa, the coverage situation is more acute, so 2G support is even more critical.

There are, perhaps, two different, yet key, scenarios that illustrate just how important maintaining cellular connectivity has become.

  1. The first one is that of a device such as a utility cellular-connected smart meter. Compared to 4G, 2G requires relatively more energy during operation, but that isn’t a concern for an electricity meter, where 2G is a viable fallback option. Delivering a short-term 2G fallback capability for a gas and water meter is still a viable option subject to the energy capabilities of the meter’s battery.
  2. The other scenario is when a vehicle is equipped with a cellular tracking device for fleet management. Vehicles need to be tracked along cross-continental journeys from the point of departure to the destination. The ability to track vehicles and goods continuously, in terms of route management, fuel consumption optimization, goods condition, including temperature, humidity, and extreme mechanical shock, may be a contractual obligation. This is particularly the case for raw or processed food, certain liquids, and medicines. As an example, in locations where 4G is not available 2G provides an essential and reliable fallback alternative.

Both of the above scenarios fall into the Cellular IoT category, and typically the amount of data transmitted each time is relatively small. For developers of IoT devices such as smart meters and vehicle telematics, 2G can provide a viable fallback from 4G/5G infrastructure. While 2G fallback is essential for tracker applications where 4G coverage is unreliable, 2G is unfortunately less power efficient, so should only be considered an alternative option.

Complementary 2G fallback for reliable 4G/5G communication

As already mentioned, the infrastructure is not disappearing as rapidly as initially thought, something that will probably only happen once 4G coverage has achieved that of 2G and is priced accordingly.

Also, if a device is only to be used within a city, or requires only infrequent or occasion network access, the need for a 2G fallback capability is not necessary. However, for those many applications where securing 100% coverage is crucial, or where the device manufacturer does not know the likely end-use cases, implementing a 2G fallback capability is prudent.

There is no doubt that the 2G network will be discontinued in a few years. From a tracker product perspective, particularly for use in those countries where the 2G network is still needed, the only way to guarantee a long-term operation is to deploy dual or triple mode devices. A 2G network capability should be provided to ensure complete coverage with LTE CAT-M1 and NB-IoT promising to fulfil reliable connectivity for the future.

For the smart meter or tracker developer, the selection of a cellular transceiver or wireless module needs to consider the inclusion of a 2G capability. Selecting a single chip with a 2G capability in addition to dual mode CAT-M1/NB-IoT or single mode NB-IoT support, greatly simplifies the bill of materials cost and inventory management challenges. For the meter or tracker manufacturer, procuring, stocking, and managing only one wireless component that meets all the protocols required, from 2G to 5G, rather than multiple devices, can save money, logistics effort, and purchasing time.

Achieving 100% network coverage capability requires a reliable and robust fallback option, and 2G can fulfill this crucial role for applications that need it. Many of the regions of the world still rely on an aging yet essential 2G infrastructure, which at some stage will be replaced. However, until that day comes, 2G continues to prove its worth as a reliable back-up solution.