Joe Madden

Two years in the past, speaking about 6G was a joke. Not anymore. Now that 5G base stations are rolling out in manufacturing, the superior R&D groups of 100 firms are turning their collective consideration to “what comes subsequent.”

In each technology up to now, the engineers have led the method, driving towards sooner information charges and better spectral effectivity with every step. Extrapolating the development of the previous 30 years, college professors now are testing ever-higher frequency bands, and dreaming about cellular hyperlinks at speeds within the Tbps vary. It is a mistake.

From 1990 to 2020, the speed-driven strategy matched up with market necessities fairly nicely as a result of we had spectrum that was capable of propagate nicely and penetrate indoors. Now issues are totally different.    

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Terabit hyperlinks are a terrific thought, however there’s an issue if you happen to suppose that that is the following “G.” The economics of the market won’t assist widespread deployment of networks at 100 GHz, as a result of a number of issues:

  • Radio alerts above 90 GHz don’t penetrate any obstacles, together with partitions, home windows, or the windshield of your automobile. An entry level in a single room gained’t even work for the adjoining room.
  • Reflections aren’t predictable with the small wavelength of alerts at 90+ GHz. Operators are attempting to make use of reflections for NLOS 28 GHz and discovering that the connection is just not secure, as a result of tiny modifications as a result of temperature or moisture can change the angles of a slender beam’s reflection.
  • Propagation within the excessive frequency bands doesn’t enable radio alerts to journey very far. The air itself absorbs vitality, leaving us with very brief vary for the envisioned 6G networks.

The above record of issues aren’t merely engineering challenges to beat… they’re fundamental physics. Don’t struggle towards God.

If you’re confronted by a roadblock, it may be helpful to cease and suppose: What’s my vacation spot anyway? On this case, it’s more and more clear that pure pace is just not the purpose anymore. No person actually wants terabit pace to their cell phone. We now have cellular networks that may run as excessive as 2 Gbps in the present day, however nearly no one makes use of an app that requires greater than 50 Mbps. 

Four years ago, I began to say that pace doesn’t matter anymore. Individuals instructed me that “apps that use gigabit information will come alongside.” However hey, right here we’re with nationwide 5G networks and no app is even near utilizing the height pace. When nationwide 4G networks have been deployed, Uber and Google Maps had already been available on the market for 3 years or extra. Instances change.

So, chasing sooner pace is just not an ideal match with the market want. The unsolved downside within the cellular market is about methods to ship cellular information capability the place the individuals are, not methods to ship sooner information to some line-of-sight places.  

As an alternative, I suggest a distinct route for the thrust of 6G. We should always focus our 6G consideration on TV white areas, land-mobile radio bands, radionavigation bands, navy bands, and different spectrum beneath 6 GHz. We now have already demonstrated that shared spectrum can work nice. Cognitive radios for LAA and CBRS can sense the presence of different radio transmitters and alter their parameters. Let’s apply these cognitive radio methods in areas the place the spectrum is simply flippantly utilized, and reap the benefits of spare channels, protection holes, and slack time on present radio providers.

Our calculations point out that beneath 6 GHz, as a lot as 3.5 GHz of spectrum is utilized in ways in which depart gaps in both time, frequency, or location. Precious low-band spectrum is dedicated to radio and tv broadcasts, that are phasing out within the age of podcasts. As a lot as 400-500 MHz is dedicated to “radionavigation,” which is actually out of date within the age of GPS. 

I agree, a few of these radionavigation aids are essential. For instance, at 4.2 GHz each plane makes use of a radar to measure its top above the bottom. Let’s depart that band alone, okay? However many different navigation aids are not vital, or might be operated at a ten% obligation cycle with out anyone getting misplaced.

Even when the trade can solely harvest 30% of the obtainable spectrum beneath 6 GHz, we might extract one other 1100 MHz of spectrum for true cellular communications. That’s double the obtainable cellular spectrum in the present day. (This calculation is for the crowded American market. In different markets we imagine the obtainable spectrum could be even richer.)

To me, 1100 MHz of low-band cellular spectrum is much extra invaluable than 100 GHz of spectrum within the excessive millimeter-wave bands. If we’re going to spend eight years on blue-sky R&D, let’s focus the trouble on one thing actually helpful.

Joe Madden is principal analyst at Cell Consultants, a community of market and expertise consultants that analyze wi-fi markets. 

“Business Voices” are opinion columns written by exterior contributors—typically trade consultants or analysts—who’re invited to the dialog by FierceWireless employees. They don’t symbolize the opinions of FierceWireless.