While 5G attracts most attention, operators had been making decisions on how to retire legacy 2G and 3G networks to free up spectrum for LTE networks and support higher capacity. Unlike earlier technology migrations where the path was clear, operators have to make tough decisions on which network to turn off first: 2G or 3G. In this, we find that operators are highly pragmatic focusing on revenue and service maximization. Understanding the practical implications sheds light on how the future could unfold.
The Drivers
The decision on which network to turn off could be complex. But in reality, two factors determine the outcome:
1- Coverage: Operators don’t want to lose coverage, so they turn off the network with the smaller footprint.
2- Devices: Machine-to-machine devices, such as point-of-sale devices, are harder to migrate to new technology than consumer devices. This involves clients obtaining new, often more expensive, devices; canceling or changing commercial agreements, and truck rolls for field upgrades. Operators opt to maintain the network where a large install base of M2M services is generating revenue. For example, Deutsch Telekom decided to maintain its GSM network to support existing M2M services. Many other operators in Europe favored a similar approach.
A third reason that influences operator’s strategy is the 2G and 3G technology. China Mobile is turning off its 3G network because it is based on TD-SCDMA which has no international footprint. China Unicom on the other hand is switching off its GSM network first. Verizon, Bell (Canada), and other North American and Japanese carriers took similar decisions in retiring their CDMA-based networks.
Operators often need to maintain legacy networks to support voice services. This makes VoLTE imperative to relax the constraints on network migration. VoLTE provides a more efficient solution for voice services than circuit-switched 2G and 3G technologies. With LTE at least 2x more efficient than 3G, it is compelling to turn off legacy networks at the earliest opportunity.
Lessons Learned
The migration to LTE took different paths. For the first time, the world has settled on a single technology after two decades of having multiple competing technologies. There are a few lessons to learn as the industry stands at the cusp of 5G deployments:
1- Enterprises and operators need to carefully consider the technology for wide-scale IoT/M2M deployments and how to partner on such services. Some IoT applications have a 10 – 20 year life span which could strand enterprises or prevent operators from upgrading to a new technology. Given the LTE technology specifications, the cost of migration is higher in the future, so this point requires special attention.
2- LTE will be around for many years to come and serve as the backbone of wireless technology. There are still many areas for LTE to reach, especially in rural communities.
3- Implementation of VoLTE will free operators from the need to roll out legacy technologies as is happening today in some rural markets to support voice services. I come across this often, where operators are compelled to extend 3G coverage to serve as voice fallback.
Forward View
I don’t think of 5G as a discontinuity in technology such as the case with prior technologies. Rather, 5G is a natural evolution of 4G designed to fix shortcoming of LTE and to implement new features. 5G will be rolled in phases and, over time, will converge to the vision that 5G promises. With this in mind, LTE will be the workhorse for wireless connectivity for many years to come. It will become useless to speak of generations as the definition dilutes and will be increasingly more difficult to distinguish one generation from another!