You see it mentioned in countless phone commercials, and your phone might use it. But do you know how it works?
You’ve likely heard a lot about 5G lately. But what is it, exactly?
5G is the latest standard for mobile internet networks.
Mobile telephone services have technically been around since the 1940s. But those systems involved dialing an operator on 80lb. car phones. And networks could only handle a few calls at once, since the Federal Communications Commission wouldn’t let them use much of the radio spectrum.
Over the next few decades, engineers at AT&T’s Bell Labs devised plans for a mobile network that could span across the country. They envisioned a dense network of hexagonal “cells” with transceivers at the center of each.
Each cell had a tower to receive radio waves from phones nearby and transmit them to a switchboard operator (soon replaced by electronic switches). The call was then routed through physical lines to whoever the caller was trying to reach. The responses on the other end are transferred back via the same route, in reverse, and transmitted from the cell tower to the mobile caller.
Different stations could operate over the same frequencies as long as they weren’t right next to each other.
In 1972, electrical engineer Amos E. Joel Jr. devised a system for callers to stay connected even as they moved from one cell to another: a “handoff” from one tower to the next.
A year later, Motorola developer Marty Cooper invented the first cell phone: the DynaTAC.
It came to market in 1983, the same year that Ameritech—a company broken off from the Bell System monopoly before it was acquired by AT&T—launched the nation’s first 1G network.
Subsequent generations of mobile networks added new capabilities, even as the general approach stayed the same. 2G switched from part-analog to fully digital radio systems, a change that enabled texting. Further increases in bandwidth meant 3G phones could access the internet, and 4G supported high-speed internet.
And now we have 5G. The latest evolution uses new technology to connect users to the network more reliably and achieves much faster speeds.
5G mobile networks can transfer data at more than a gigabit per second, vs. 4g networks that typically offer speeds closer to 50 megabits per second. And they do this with half the latency of 4G ones. That means it takes half as long for your web requests to come back. When you’re streaming a game, this translates to reduced lag.
Engineers hope 5G will eventually connect more than just phones. It could also link sensors embedded in everything from farm machinery to medical devices, forming the so-called “internet of things.” That’s been difficult with the lags of 4G.
5G has required a host of new technologies.
5G works much better in crowded areas because it carries data over a wider range of frequencies—for the first time, utilizing the super-fast millimeter-wave spectrum. mmWave wavelengths are a few millimeters long. They are much higher-frequency than the radio waves 4G has used. Faster waves can carry more data, which means incredibly fast data transfers.
Another innovation keeps 5G from killing your phone’s battery so that you get full use of that data speed. The feature, called “adaptive bandwidth,” lets your phone automatically switch to faster, more battery-guzzling internet speeds when you need them, and preserve power when you’re just doing low-data activities like checking email.
Lots of the advances associated with 5G involved the infrastructure of the network, like transitioning from a cell tower system to a denser grid of “small cells”: which are radio transceivers the size of pizza boxes that can be mounted onto street lights or buildings. Some could also be installed indoors to create private networks for homes or other businesses. Since 5G is likely faster than your home WiFi, it could end up being your only internet connection.
And through a feature called “sidelinking,” developers plan to make 5G devices communicate directly with each other, without necessarily routing the signal through transceivers. That means, for instance, 5G-equipped vehicles would be able to coordinate more efficiently, an important feature for self-driving cars.
The fastest 5G signals travel by mmWave, but those signals can only travel short distances. So bringing those speeds to the masses will require small cell infrastructure—which still has a long way to go.
5G isn’t replacing 4G—it’s simply being built on top of it. So phones that support 4G will continue to work for a while. Even 3G phones still work, though that’s likely to change soon—for the 17% of US subscribers currently using 3G, they should expect their phones to stop working sometime in 2022.
Lots of providers already offer “low band” 5G. Those signals travel incredibly far, but they’re about the same speed as 4G. “Mid band” is somewhere in the middle, offering faster speeds than 4G, but hardly the revolutionary upgrade that the technology will eventually support.
This is important, because it means people with 5G-capable devices can connect to 4G networks that are currently much more widely available. Though eventually, your 4G phone will be about as useful as an original iPhone that ran on 2G, or a Motorola DynaTac brick from the 80s, which supported 1G.The big questions with 5G, though, are when we’ll get it, and what we’ll do with it once it’s standard.
While the majority of the world will have access to 5G within several years, poor and rural areas may be left waiting: the infrastructure is very costly, and many people in developing countries are still using 2G devices. This has led some to worry that 5G could widen the gap of internet accessibility. Since wireless access is a huge driver of economic growth, that may only deepen economic division.
Regardless, 5G is coming. It’s just the next step in mobile networks. Soon, it may change the way we think about the internet: from a useful and entertaining tool, to a framework that connects everything around us. A technology that you thought of as merely helping your cell phone will soon have a greater impact on your digital life.