For many of us, LTE TDD is a bit like an albino squirrel.
We've all seen, maybe even played with, squirrels. We might have heard that albino versions exist in the wild. Yet, we've never actually seen them first hand. Get the analogy? As much as we might take LTE services for granted and understand the broader industry dynamics around LTE TDD, most of us have never actually used LTE TDD services. This makes LTE TDD something of an abstract concept.
In reality, there's nothing abstract about LTE TDD. We can go back to the beginning to LTE standards development to look at the hopes and expectations for a grand, unified ecosystem but deployments (and services) in the here and now tell a concrete story.
There's no denying China Mobile…or is there? A few years back, as people first began talking LTE TDD, it was difficult to (almost impossible, really) to have an LTE TDD discussion without China Mobile (CMCC) being a part of it. This was completely understandable. As the world's largest mobile operator in the largest single telecom market, CMCC's commitment to LTE TDD promised to help move the ecosystem forward. What's more, think about Chinese vendors who previously built TDD know-how via TD-SCDMA product development. Where that expertise supports LTE TDD development, Chinese vendors should benefit from larger market opportunities, at home and abroad. There is a reason, after all, why Bands 39, 40, and 41 are so well-represented in the TDD devices that have been launched to date. Yet, as much as it may have been tough to separate CMCC from initial LTE TDD discussion, there was no difficulty separating CMCC from initial LTE TDD deployments. Those same bands are available in many markets outside China, and LTE TDD's scale supports operator economics no matter where they are. Per the Global mobile Suppliers Association, 39 LTE TDD networks have been launched in 26 countries. Yep, that's China plus 25 other countries. China Mobile plus 38 other carriers. And, in many ways, those other carriers have led the charge. Think back to 2011. As China Mobile was kicking off a trial of 1,000 LTE TDD base stations, the technology was getting attention everywhere from Australia to Denmark, France to Taiwan…with India in between. Where LTE TDD was developed on a global stage, deployments speak to its global nature and interest.
There's no denying the ecosystem…really. Like LTE, WiMAX was also going to be a "global" technology and it amassed enough deployments across the globe in order to claim success on that front. What it didn't manage to do was build enough ecosystem scale to enjoy sustained, mass market success. How does LTE TDD compare circa 2014? Let's start by going back to that GSA data from August 2014: 530 devices supporting LTE TDD, or about 28 percent of the LTE total; solid growth (more than 2x) in LTE device totals; solid growth (more than 3x in share) in the smartphone category; solid supplier diversity with 85 vendors making LTE TDD devices, or about half the LTE total. Yet, there's another, less abstract, way to look at the question. It looks a lot like the iPhone 6. As one of the Sprint Spark devices, it sits in the carrier's portfolio of LTE TDD devices alongside flagships like the HCT One M8, Samsung Galaxy S5, and LG G3. Sure, it's nice to point to a deep portfolio of devices helping to move the LTE TDD ecosystem forward, but it's just as important to have compelling devices people want to buy, developed by vendors who know there will be a big enough market (markets, actually) to sell these into.
- One happy LTE family. The Sprint example raises another interesting consideration: carrier deployments of LTE where TDD and FDD implementations live alongside one another. In Sprint's case, we're talking FDD at 800 MHz and 1900 MHz with TDD coming in at 2.5 GHz. Billed as a solution for supporting coverage and capacity demands (not just a way to make use of available spectrum), Sprint's not alone in this type of co-deployment. Remember that GSA report? It points to 13 operators deploying LTE in both TDD and FDD, across paired and unpaired spectrum. And outside commercial activity, Ed Gubbins here at Current Analysis recently pointed to a handful of TDD-FDD carrier aggregation trials as a way in which vendors are looking to differentiate in the LTE Advanced space. The interest in carrier aggregation across TDD and FDD bands isn't surprising; in order to support usage demands, carriers will--naturally --want to use all of the spectrum assets available to them, including the TDD spectrum many carriers around the world have been sitting on. The other message here, however, is that the reality around LTE TDD is matching initial hopes around it. Namely, a harmonized LTE standard has made co-deployment of TDD and FDD a reality from a technical standpoint (how to get services deployed) as well as a commercial standpoint (how to actually make those services a success).
This last point is particularly important. If we're talking about a coherent standard--one harmonized ecosystem, supporting LTE TDD alongside FDD--operators and vendors both benefit. Operators get to deploy (are deploying) services in the spectrum they have. Vendors get to develop TDD products (network and client) with global opportunities. Where so many telecom "hopes" fall flat, it's nice to see this one materialize. It's no albino squirrel, but it is pretty cool.
Peter Jarich is the VP of Consumer and Infrastructure at Current Analysis. Follow him on Twitter: @pnjarich.