Enlarge / Artist’s impression of 5G speeds in millimeter wave.
Aurich Lawson / Getty
The long-acclaimed fifth generation of wireless communication is not magic. We are sorry if you expect otherwise due to an endless hype about the world-changing possibilities of 5G. But the next generation in mobile broadband will still have to comply with the current generation of natural laws that determine how far a signal can travel when it is transmitted in certain wavelengths of the radio spectrum and how much data it can carry.
For some of us, the results will yield the billions of bits per second in transit that occur in many 5G sales pitch, going back to early specifications for this standard. For everyone else, 5G is likely to deliver a pleasant and valued upgrade rather than a renaissance of bandwidth.
That does not mean that 5G does not offer interesting possibilities in areas such as broadband and connectivity between machines. But in the form of wireless connectivity for mobile devices that we know best, 5G marketing controls have written that the actual 5G technology will cause many problems in cashing.
A furious family of frequencies
The first thing you should know about 5G is that it is a family affair – and sometimes dysfunctional.
Wireless providers can bet 5G on each of the three different ranges of wireless frequencies, and one of them does not work like the current 4G frequencies. That is also the reason behind the most mean 5G predictions.
Millimeter-wave 5G takes in bands that are much higher than those currently used for 4G LTE – 24 gigahertz and higher, far above the 2.5 GHz frequency of Sprint, the highest frequency band used by major US airlines to date is used.
At those frequencies, 5G can transmit data with fiber optic speeds and latency – 1.2 Gbps of bandwidth and latency of 9 to 12 milliseconds, to quote figures from an early AT&T test. But it can’t send them far. The same 2018 demonstration meant a direct line of sight and only 900 feet from the transmitter to the test location.
That distance and sightlines are still adhering to, although the American airlines have pioneered that millimeter-wave 5G, saying they are making progress in pushing out.
“Once you have sufficient density of mobile sites, this is a very strong value proposition,” said Ashish Sharma, executive vice president for IoT and mobile solutions at the wireless infrastructure company Inseego. He pointed in particular to recent progress in resolving long-term problems with multipath reception when building signals bounce off.
Enlarge / Many “5G” images are available. Some of them are more optimistic than others. This is one of the most optimistic.
Photographer is my life / Getty
However, reception in those buildings remains problematic. This also applies to intervening foliage. That is why fixed-wireless internet providers that use millimeter wave technology such as Starry have opted for externally placed antennas at customer locations. Verizon also sells home broadband through 5G in a handful of cities.
Under millimeter waves, wireless providers can also operate up to 5G on medium and low band frequencies that are not that fast or responsive, but extend much further. So far, 5G implementations outside of the US have largely adhered to those slower, lower frequency bands, although the industry expects the acceptance of millimeter waves abroad to accelerate in the coming years.
“5G is a little more spectrally efficient than 4G, but not dramatic,” emailed Phil Kendall, director of the service provider group at Strategy Analytics. He added that these limits will be the most profound on the existing LTE spectrum that has been converted to 5G usage: “You will not be able to suddenly give everyone 100 Mbps by re-growing that spectrum to 5G.”
And even the American airlines that today preach millimeter-wave 5G also say that they will rely on these lower bands to cover much of the states.
For example, T-Mobile and Verizon stated at the beginning of this year that millimeter waves do not work outside urban areas. And AT&T waited until the end of November to launch low-band 5G to start selling services to consumers at all; the low resolution maps that it placed show that connectivity extends to suburbs.
Sprint has meanwhile opted for the launch of its 5G service on the same 2.5 GHz frequencies as its LTE, with coverage that is much less diffuse than millimeter-wave 5G. Kendall suggested that this mid-band spectrum offers a better compromise between speed and coverage: “Not the 1Gbps millimeter-wave experience, but certainly something sustainable that is much higher than 100 Mbps.”
The Federal Communications Commission is working to make more mid-band spectrum available, but that won’t lighten American smartphones for the time being.
(Disclosure: I have written a lot for Yahoo Finance, a news site that owns Verizon.)