State of Mobile Networks: USA (February 2016)

The U.S. is a bit of a 4G enigma. It was one of the first countries to launch LTE back in 2010, and in the intervening five years it’s built one of the most extensive mobile broadband infrastructures in the world. U.S. 4G subscribers can expect to connect to an LTE network 81% of the time. According to our upcoming State of LTE report, the U.S. ranks among the top 10 countries in the world in terms of availability, which is all the more impressive considering its broad geography. Most of its peers in the top 10 tend to be small and densely packed countries like Singapore and South Korea. (Though T-Mobile and AT&T refer to their HSPA networks as 4G, we use the term 4G solely to describe LTE networks.)

But that same network robustness doesn’t apply to 4G capacity. The U.S. is falling far behind globally in LTE speed. As many other countries start providing consistent 20 Mbps or greater connections, the U.S. average is 9.9 Mbps. That puts it in the same league as Argentina, a country that launched its first LTE network a year ago. That’s not to say that U.S. operators are delivering a poor LTE experience to their customers — 10 Mbps is more than enough to power any app on a smartphone — but the U.S. clearly is no longer pushing mobile technology boundaries like it used to. Before we delve deeper into the reasons why, let’s take a closer look at the dynamics of the U.S. market.

T-Mobile begins to deliver on coverage promise

In a year-end blog post, CEO John Legere predicted that T-Mobile would surprise the world with the gains it made in coverage in 2015. Last year it started a nationwide rollout of LTE on the 700 MHz airwaves — low frequency spectrum intended to boost its coverage both outside of cities and into the hard-to-reach interiors of buildings. According to our measurements, T-Mobile is delivering on Legere's boasts. In the fourth quarter, T-Mobile had an LTE availability (*) of 81%, which means its 4G customers were able to see an LTE signal 81% of the time in our tests (for more information on availability see our methodology page). T-Mobile's recent improvements now put it a little more than a percentage point away from matching AT&T in LTE network availability and helped it close the bigger gap between itself and Verizon. Sprint brought up the rear with an availability of 70%.

In past reports, T-Mobile has bested all operators in speed, but in the fourth quarter T-Mobile and Verizon were almost evenly matched. T-Mobile's 12.3 Mbps LTE average just barely edged out Verizon’s average of 12 Mbps, making it a statistical tie (AT&T and Sprint didn’t even come close). We delved deeper into our data to compare LTE speeds in the eleven biggest metro areas and found Verizon and T-Mobile battling out just as intensely on the local level. T-Mobile won the contest in four markets and Verizon won it in three, while three cities were statistical draws between the two (the 11th market, Houston, was a statistical tie between all four nationwide operators). Verizon still has the advantage in availability. It's king when it comes to reliability, scoring an availability metric of 87%.

Latency: Often overlooked, but critical to VoLTE

One final metric we would like to explore is latency, which measures the time it takes for data to make a round trip through the network. Low latency is important to overall quality of experience on a smartphone — webpages start loading faster — but it's critical to voice over LTE (VoLTE) as a lower network reaction time means a better quality call. Verizon, AT&T and T-Mobile have all begun moving their voice traffic from 2G to LTE networks. Surprisingly, though, the operator with the lowest latency is the one major provider that currently has no VoLTE services, Sprint.

That transition to VoLTE could help U.S. operators solve their 4G capacity problems. The majority of voice calls still go over 2G networks, but as U.S. operators move that traffic over to LTE they can start shutting down 2G networks and use that spectrum for 4G. T-Mobile recently stated that 40% of all its voice calls are now VoLTE calls. One of the reasons T-Mobile has made such big speed gains in recent years is it has been gradually turning off its 2G networks and putting that spectrum to work in its LTE network.

LTE Advanced boost hampered by spectrum

The U.S. won't catch up with the rest of the world solely through cannibalizing its 2G networks though. Its problems are a bit deeper, and they're both political and technological. One of the main reasons why countries in Europe and Asia have been able to deploy such ultrafast networks is that they're tapping into new and larger blocks of spectrum that can support much more 4G capacity and much faster connections. Furthermore, many of these international operators have been quite aggressive in their pursuit of new technology. They're using LTE-Advanced techniques to tie multiple spectrum bands together, allowing them to boost individual device speeds even higher.

The last major 4G spectrum auction in the U.S. was in 2008, and in the last few years most U.S. operators have been adding to their holdings through acquisitions and trades. As for LTE-Advanced, its use in the U.S. has been fairly limited, in part because U.S. operators don't have big blocks of spectrum to tie together. Another problem is the success of U.S. operators in signing up 4G subscribers over the last five years. So many customers competing for limited capacity means that average connection speeds are driven down.

There's still hope that the U.S. can get back in the global LTE speed race. This year the Federal Communications Commission plans to auction off a major chunk of the broadcast TV airwaves for mobile broadband use. Depending on how much spectrum is released and when it becomes available (it may very well be reserved for future 5G networks), U.S. operators could use those frequencies to reach parity with the world's LTE speed demons. But until then, the U.S. may well have to be content with being the tortoise of the 4G world: slow but reliable.

(*) Editor’s note: When this report was originally published OpenSignal used the term time coverage for what is now our availability metric. We changed the name to avoid confusion of this metric with geographic and population coverage metrics, and we have reflected that change in our old reports. The new terminology, however, does not reflect a new methodology. Time coverage and availability represent the same measurement: the proportion of time OpenSignal users can connect to a particular network.