Where 5G Works, And Where It Doesn’t

Just because millimeter wave technology is built into a handset doesn’t mean it will be useful.


The rollout of 5G hype has begun. Companies are building 5G chipsets for mobile devices, and they are working on the infrastructure that will allow massive amounts of data to move freely between devices.

There is little doubt that more bandwidth is required everywhere. Files are growing in size, particularly with streaming video and images and various flavors of AI and machine learning. This is evident in architectures that are being developed to reduce latency and improve throughput. But there are two very distinct sides of 5G, and both of them will not be useful everywhere.

One involves millimeter wave, which tends to get lumped into almost everything as the metric for massive data throughput. When companies talk about 5G technology to guide autonomous vehicles, robots, drones, or any other device that needs instantaneous communication capabilities and large amounts of bandwidth, they are implying that it will be all about millimeter wave. The reality, however, is beginning to look rather different.

To begin with, cars will not be able to rely on 5G connections everywhere without flooding the roadways with high-frequency radio waves. That alone will cause interference. And even in the best of situations—consistent connections, empty airwaves, no traffic—it would take far too long to send signals to the cloud and respond in time to avoid an object at 70 mph. Add in another car on a collision path at the same speed, and those systems would have to send signals and receive instructions back in half the time. And that’s on a highway, where at least in theory there could be sufficient millimeter-wave infrastructure to make this work.

Now consider a handset, which will be constantly searching for a signal because millimeter wave technology is interrupted by objects, dust, heat, precipitation, leaves, or just about anything else that might blow in from any direction. Millimeter wave signals work great point-to-point, but they don’t penetrate walls, go around corners, or even go through glass. While beamforming is an interesting approach, the number of small cells and cell towers required to replace 4G is mind-boggling, and the amount of power it will require to both send and find signals will be huge.

And this disregards any possible impact mmWave technology could have on health. Studies on that are just beginning, and they will take years to make a determination.

What does seem to make sense, particularly in handsets, is sub-6GHz 5G, which behaves roughly the same way as 4G. Signals will continue around corners and improve performance of 4G LTE systems, although not anywhere near the speeds advertised with millimeter wave technology.

Where 5G mmWave technology appears to make sense, at least so far, is with fixed infrastructure. A building with a millimeter wave connect can send and receive enormous amounts of data quickly, and because it’s not moving 5G signals can be directed in a line of sight. Think about the Internet speed in a hotel that promises high-speed Internet, and then think about that in exponential terms. For office buildings, one connection could boost all wireless speed from a central hub, and in farming regions it could be used to automate farming at a level never before possible.

5G will happen, and it will bring greatly improve what can be done wirelessly. Still, the biggest benefits may show up in new applications, rather than existing applications using what appears to be much more of the same. 5G is a market-changing technology, but it’s too early to say which markets.

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