FOSTER CITY, Calif. — Given all the time that most of us have spent at home recently, it’s easy to lose sight of advances in technologies like 5G that are generally more useful when we’re out and about.
However, just as municipalities around the country have used reductions in traffic to speed up road improvement projects and other infrastructure enhancements, so too have several of the U.S.-based telco carriers been working to bring 5G to life sooner than originally anticipated.
Just last week, AT&T announced that it had achieved nationwide coverage for its 5G network, joining T-Mobile, who reached that important goal last December. In both cases, the companies are using what’s called “low-band” frequencies to achieve these nationwide networks. The reason this matters is that cellular signals which are transmitted at these lower frequencies (600 MHz for T-Mobile and 850 MHz for AT&T) are able to travel long distances. This means you can create a bigger network with fewer cell towers.
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The problem is that the width of the “lanes” used to transmit data at those frequencies are very narrow, which means that the speeds you can get while using them are not much different from 4G. Needless to say, that’s certainly not what we were led to believe 5G was going to be able to do.
You can get significantly faster 5G download speeds using a technology called millimeter wave (mmWave), which transmits data at much higher frequencies (such as 39 GHz) and, most importantly, offers significantly wider “lanes” for data traffic. The problem with mmWave is that the signals don’t travel far (think, roughly a city block), and they’re highly susceptible to interference, including things like windows, walls, and even other people.
If you can get mmWave 5G service (which all three major US carriers have enabled, but only in a few cities around the country), it can deliver download speeds that are 50x faster than 4G. The huge caveat, however, is that you have to be outside, not moving, with few people around and located in the right section of the cities where the service is turned on.
In real-world tests of Verizon’s 5G network, which only uses mmWave, a measurement company called Open Signal found that people were actually only getting 5G service 0.4% of the time. If you’ve spent a lot of money on a 5G phone, that’s probably not going to make you very happy.
The most interesting near-term options for 5G are around what’s called “mid-band” spectrum, which means radio frequencies in the roughly 2.5-3.5 GHz range. Thanks to its acquisition of Sprint, right now T-Mobile is the only U.S. carrier that is using these frequencies, although both AT&T and Verizon have talked about using them at some point in the future.
The quality of 5G service when using these mid-band frequencies turns out to be a very solid compromise of good coverage (although not quite as wide as the low-band frequencies) with traffic lane sizes that should accommodate a very respectable 10x speed increase over 4G.
In addition to basic frequency developments, the carriers have also been working on other enhancements to their 5G networks. AT&T, for example, announced about a month ago that they have turned on a technology called DSS (Dynamic Spectrum Sharing), which allows 4G and 5G phones to use the same frequencies. Practically speaking, that means AT&T can use some of its huge range of 4G coverage to also carry 5G signals, which can lead to both better coverage and faster download speeds.