Despite 5G Hype, still a Compelling Roadmap for 4GReading Time: 3 minutes
5G was the dominant topic of conversation at this year’s Mobile World Congress. While this might be the sexiest topic in telecom right now, there’s still a compelling 4G LTE roadmap, incorporating many of the capabilities promised for 5G – especially the earlier, ‘pre-5G’ versions that have been discussed. What’s clear about 5G is it will roll out in stages, it will be messy, and there will be multiple “versions” of 5G.
Meanwhile, what about 4G, the LTE workhorse we all know and love? Well, there’s still a lot of gas left in the LTE tank. First, even though the US, Japan, South Korea, and a handful of other countries have 80% or more of their subscribers on 4G, that number is still less than a third of total subscriptions globally. So there is still substantial investment going into 4G. Second, even as 5G is deployed, LTE is going to provide the primary coverage layer for the foreseeable future – likely out to 2025 – even among the ‘early adopter’ 5G countries. That’s because 5G is likely to be deployed in islands or pockets until the business case is truly proven. And it will require a massive number of small cells which, as we’ve learned with the early stages of the small cell market, are difficult to deploy at scale.
Most importantly, there is still a compelling roadmap for LTE, promising significant improvements in speed, latency, and spectral efficiency. Much of what is promised for 5G — especially the pre-standard or early stages of 5G — can be accomplished within the LTE roadmap.
LTE Advanced, which was introduced a couple of years ago, has already delivered speeds exceeding 100 Mbps and a 2x or greater boost in capacity per MHz, using carrier aggregation, 4×4 multiple input (MIMO) antennas 256 quadrature amplitude modulation (QAM), and an assorted soup of technologies with even less user-friendly acronyms.
The roadmap for the next two to three years is equally compelling. The next stage is called LTE Advanced-Pro, which some call 4.5G. Some of the capabilities include:
• An even higher number of potential ‘carrier aggregation’ channels (from 5 to 32)
• Support of much wider spectrum bands
• Peak data rates up to 3x that of LTE advanced
• Latency improvements of 50% or more
• Further MIMO enhancements, for better coverage
• Support for unlicensed spectrum, such as 5 GHz
• A host of enhancements for IoT, to support lower speed, narrow band access for low power devices
All this added together promises significant increases in throughput, improved latency, greater spectral efficiency, and other improvements. If you thought we needed to wait for 5G for gigabit services, think again: last year, Qualcomm introduced the X16 modem, which is the first commercial modem to support Gigabit LTE up to 1 Gbps—that’s LTE Cat 16—by using four antennas to simultaneously receive 10 LTE data streams boosted to around 100 Mbps each through advanced signal processing. In reality, the operators won’t offer gigabit LTE, just as peak 5G speeds of 10 Gbps represent more of a theoretical than a practical number.
Another key aspect of LTE Advanced Pro will be using carrier aggregation in the unlicensed bands, such as 5 GHz (used by WiFi). Contentions around this issue were ironed out late last year and we should see services such as LTE Unlicensed (LTE-U) rolled out as soon as this summer, delivering business case-driven speed boosts and capacity increases. This, plus additional bands of 700 MHz, AWS, and eventually 600 MHz spectrum being deployed or becoming available soon, provide a lot more ‘real estate’ to increase channels. That translates into faster speeds and more capacity. The fact the operators are now all offering some flavor of an ‘unlimited’ plan, even with asterisks, reflects their increased optimism with respect to the capacity picture.
The significance of all this is many of the improvements and attributes touted for 5G, especially in its early stages, will be delivered within the LTE roadmap. Now, how exactly LTE Advanced Pro will be marketed is an interesting question. Remember when Metro PCS and Verizon were the first operators to deploy LTE in 2010? Within a few months, AT&T and T-Mobile branded their HSPA+ services, which technically were still 3G under the 3GPP framework, as ‘4G’. Some cried foul although, in reality, HSPA+ in some markets outperformed LTE (it was very situational). Still further, what was originally promised for LTE really wasn’t delivered until some of the first LTE Advanced Services started to be incorporated, circa 2013.
This playbook is likely to be (already is being?) replayed with respect to 5G. I would not be surprised if some operators branded aspects of their 4.5G services as 5G. They might call it ‘Pre-5G’. But ‘4G Plus’ and ‘5G Minus’ are likely to be much the same thing, from the standpoint of the user experience.
The bottom line is we don’t have to wait until 2020 or later for some of the significant improvements promised with 5G. There will be material increases in speed, latency, and capacity along the LTE path and those capabilities are already part of the 12 to 18-month roadmap of the major device vendors. So, while 5G might grab all the headlines, there’s still lots of reasons to get excited about 4G.