Author(s): Kester Mann
A few weeks ago we wrote about Verizon's claim that it was the first carrier to launch commercial mobile 5G services (see Verizon Claims 5G Gold Medal). Some people in the industry are asserting, and with some legitimacy, that the US carrier only won the race on a technicality. Verizon switched on its 5G network with very selective coverage, just a single supporting smartphone and providing 5G services to a few small areas of Chicago and Minneapolis only hours before its South Korean counterparts offered relatively wide 5G coverage in South Korea.
In reality, 5G is still in the press-release phase of its evolution and technical historians can debate all the claims of being first to launch a 5G network. The question is no longer about who, but how. Operators and regulators are still developing strategies for rolling out 5G to the masses, assessing in particular the optimal spectrum for the next generation of wireless services.
This really is a topic for careful evaluation, given the expense and long-term implications involved. There's no such thing as "5G spectrum", nor perfect spectrum. Higher frequencies offer greater throughput but poor propagation, limited by distance and challenged by objects that happen to be in the way; foliage and even the weather can be hurdles. 3GPP has officially defined about 40 frequency bands for 5G New Radio, but this is a matter of nomenclature, not selection. Despite the unabated media coverage of 5G, only a few dozen operators around the globe have deployed 5G networks of any sort, with hundreds of other operators still in the evaluation stage.
Millimetre wave is a term being used somewhat loosely in the cellular world to describe spectrum above 24 GHz. Verizon's decision to introduce 5G services using 28 GHz spectrum is being watched closely by network planners worldwide and by rival T-Mobile, whose executives have questioned the roll-out strategies of Verizon and AT&T. Although T-Mobile initially planned to concentrate first on its 600 MHz spectrum for the launch of its 5G network, a lack of devices prompted a shift in its launch strategy, announced at MWC Barcelona 2019: the carrier has started to switch on millimetre-wave networks before it rolls out 600 MHz later in 2019. However, we believe that the order of deployment of different frequency bands will be largely irrelevant within 12 months, as a broad range of low, mid- and high bands will be necessary to provide an effective combination of capacity and coverage.
On a call for analysts about Verizon's financial results for the first quarter of 2019, CEO Hans Vestberg was forced to defend his company's deployment of millimetre-wave spectrum, following recent concerns about performance and reliability. He said that although the band is not optimized for coverage, it enables "enormous" throughput speeds and is suitable for dense urban areas, which account for most of the carrier's data traffic. Mr Vestberg added that early performance is meeting expectations but reinforced that the carrier is just at the start of a long journey and expects most handsets launched in 2019 to support millimetre-wave spectrum.
T-Mobile, like most international operators, is opting to launch 5G using spectrum below 6 GHz. The speeds aren't as impressive, but the broader coverage makes it useful in less-densely populated areas. This is a criterion that regulators in many countries are considering while designating 5G spectrum, as they auction off available spectrum bands that they believe bring some sort of balance between reach and performance.
In most countries, there will be a variety of 5G implementations, with the goal of optimizing the spectrum choice for the landscape. In addition, operators will repurpose 2G, 3G and eventually 4G spectrum for 5G services. Although there's wide interest in millimetre wave, most 5G roll-outs will be on sub-6 GHz bands.
This carries implications for the whole ecosystem, including devices. Operators jumping into millimetre wave, such as AT&T and Verizon, will encourage component suppliers and device makers to develop products that support high-frequency bands despite the limited global applicability. It's a case of the tail wagging the dog. Devices supporting 5G in millimetre wave will be more complex and expensive, which could delay rather than accelerate smartphone upgrade rates and limit other new designs for 5G.
With a limited number of users, new consumer applications for 5G could appear slower. This isn't a comfortable cycle to be in, considering the billions of dollars that are being invested. Operators that have been eager to be first with 5G could be giving others a second-mover advantage, providing free lessons and breaking ground for a wider industry entrance. Some operators will wait and see.
Many industry players are still actively evaluating the choice of spectrum, hunting high and low for what might be the optimal solution given limited availability. For now, players that have chosen millimetre wave may find that it can be lonely at the top.