Are we sleepwalking into a 6G Golden Band over-egged spectrum auction arms race?

On paper, the Golden Band (the 7–15, or in some accounts, 20 GHz frequency range), seems almost too good to be true, offering as it does an ideal half-way house between all that congested/limited bandwidth stuff under 6 GHz and the ultra-high speeds we want via wider bandwidth.

We’re reassured that it also has good propagation characteristics for outdoor and indoor environments, so good for range, too. That’s a profile that for some at least makes it a key driver for 6G take-up, as it could be the ideal basis for high-capacity, low-latency applications like XR (extended reality), holographic communication, and industrial automation—accepting that it does require new radio technology and spectrum regulation, and there are some question marks over possible clashes in at least some regions with existing satellite or military radar services.

But here’s the problem. We all convinced ourselves we had a similar magic frequency in 5G, and the payback hasn’t justified the industry’s move into it.

Will G-Band just be ‘Son Of C-Band’?

We refer, of course, to the fabled midband (C-Band in America), 3.3 GHz to 4.2 GHz, which is heavily used by 5G as offering a good balance in terms of coverage and capacity (especially over mmWave and legacy LTE bands). 

US operators alone have spent more than $100 billion in license fees ($81 billion in the C-band auction and another $22 billion in the 3.45 GHz auction; it seems like the US really went to town here) to secure their spot here—a figure that has, of course, been added to considerably by all their additional spend on compatible network equipment. 

Europe is as keen, with the GSMA recently citing industry claims that what we call the upper 6 GHz band is “essential” for Europe’s mobile future (“As leading European Telecom operators, we urge Europe to make available the complete upper 6 GHz band for mobile for the benefit of Europe’s economy and society… The upper 6 GHz band is a critical opportunity for launching 6G in Europe and should be an integral part of Europe’s future mobile infrastructure”).

But as discussed very well in Light Reading in May, respected industry analyst Craig Moffett (MoffettNathanson Research), has publicly stated that Verizon's experience of midband in the US has been, shall we diplomatically say, disappointing: "Put simply, C-Band isn't very good spectrum," he is quoted as saying.

Tell us how you really feel, Mr Moffett--but sometimes, a bit of bluntness is needed to focus the sector’s thinking. As the site’s analysis shows, there’s just some basic physics at work here that means that the lower down the spectrum you go, the easier it is to roll out easy, popular things like voice, but that the higher you go, the trickier this is to do, especially at national service levels. 

When we say ‘trickier’, we mean what Moffett calls the "uncomfortable truth" that at 3.7GHz, C-Band can’t propagate very well, especially when it comes to going through walls etc. Put simply, higher frequencies offer more bandwidth and faster data rates but require denser infrastructure (more small cells) and line-of-sight connections to be effective. 

Hence the interest in mid-range, as on paper they can strike a practical balance between speed and coverage. But a clear warning sign here is the technical and economic limitations that led to the more or less abandonment of mmWave as a consumer solution for broad 5G deployment. 

That said, mmWave has some great use cases, but not as a universal solution but in specialist apps or niche 6G or enterprise use cases where its high capacity can shine (think, places with high user density and line-of-sight like stadiums, and airports, FWA/home broadband where fibre isn't available, etc.).

Where mmWave can be carefully planned, like in industrial or enterprise campuses, it works very well. In the meantime, the sector seems determined to press on with C-Band as the consumer option, and so far, things seem to be working out well.

But the Golden Band might take us into a much less sure place, and there are many questions still to be answered about if we really are making the best use of the spectrum we’ve all so expensively invested in already (hence the notion of ‘refarming’ existing spectrum). 

6G Golden Band doubts need to be raised

At the end of the day, the industry has still failed to generate enough ROI out of the whole move to 5G. That’s a huge discussion in itself, of course, but if you accept at least some of that logic, it must be a concern that manufacturers are once again pushing us to spend on equipment and services for possible Golden Band services that may not be that lucrative at all. 

Nonetheless, all that sunk investment needs to be justified, so at least some parts of commercialising 6G will be attempted there. But there are real worries that the industry is accepting an unquestioned set of assumptions about how much better these bands are and so rushing towards something impractical.

The switch to a better use for millimetre wave suggests that there is more hope for return and the really compelling services businesses will pay for long-term might be not 6G as a national standard, but in hot spots and niche, but valuable, applications, where something like Golden Band would offer features nothing else could.

For now, Golden Band range auctions are a long way off (though Donald Trump wants that to change). But we need to learn from history about how much money we could spend on spectrum in these frequency bands, as recouping the expense of delivering coverage in them could be very challenging indeed. 

At the end of the day, telecom isn’t a science project, it is a business. As the article notes, “The next generation of mobile is unlikely to exist outside parts of that Golden Band. Finding the value in it is the challenge.” 

That has to be the mission, not seeing what envelopes we can push, and fancy equations make seemingly balance for their own sake. For sure, we don’t want to end up with the “sadness and gloom” about our band of gold that Freda feels in her song.