A couple of weeks ago my eye was caught by a GSMA headline about spectrum policy. Normally, I’m not too bothered about these. To us, spectrum is a bit like the weather. You have to deal with it, right? No point in building a business that only works on sunny days. No point in building a product that relies on infinite clean spectrum. But something about this one made me look twice. You mean the EC doesn’t have a long-term vision for UHF spectrum? The point of the story is that the GSMA is calling on the EC to accelerate the conversion of 470-790MHz spectrum for mobile broadband use. Sounds good, doesn’t it? 320MHz going spare? We could all use that. But two things about the piece struck me as misguided. Firstly that the GSMA is calling for EU member states individually to have the option to repurpose their spectrum earlier than the timelines recommended in the report, and second, are we really that desperate for spectrum that we’ll elbow other users out the way regardless. And while the article doesn’t mention it, how does this stack up with LTE-U?
At one level UHF spectrum is very like the weather. It’s mostly outdoors and wide-area. As such it’s of marginal interest to us. Our products are short-range (less than a kilometre or so) and mainly indoors, so actually I could care less about more UHF, except for one thing – in-building penetration is better at 500MHz than it is at 900MHz and much better than at 2.6GHz – and we’re starting to hear vendors and operators talk about the “outside-in” method of improving indoor coverage. This always makes me smile, as we invented the term “inside-out” when we were looking for funding for our small cell developments ten years ago, and made a pretty convincing case by analogy – would you try and heat your home using heaters on lamp-posts in the street? Of course not. A bonkers idea, and it continues to be so. If the mobile industry thinks it’s going to improve indoor coverage by blasting 700MHz spectrum in through the walls, it’s gonna have to think again.
But that’s the weather for you. If it’s blowing a gale outside, all you can do is keep the fire burning in your own hearth. Which is why, I suppose, the GSMA call, to allow EU member states to re-purpose UHF spectrum before the deadline, seems attractive at first sight. But in these days of wafer-thin infrastructure margin, companies need global scale to make their businesses work. There’s no way I could go to my board to ask for funding to develop a product for one EU country. The only infrastructure development stories that make sense these days are the global ones, and with that in mind, I reckon that the GSMA call is too half-hearted. If we’re going to repurpose this spectrum early, let’s do it Europe-wide, and make sure it’s properly aligned globally. Let’s give the EU infrastructure makers the early global market we need to maintain their leadership. And the next question is when will WRC take the big but necessary step of sweeping away these piecemeal allocations, and set out two or three multi-hundred MHz blocks for LTE with harmonised slices for GSM the world over. And that’s below 6GHz. Let’s hope that 5G doesn’t suffer the same spectrum muddle of preceding generations.
But do we need all of this UHF spectrum anyway? Well, it’s a moot point. All of the projections show orders of magnitude growth in data consumption over the coming decades, so it’s yes, isn’t it? But it’s not a uniform story. In high traffic areas, we need more spectrum than we have available. According to Prof Tafazolli at the 5GIC at the University of Surrey, this is one of the primary motivations for 5G above 6GHz. Even if we allocated all of zero to 6GHz to mobile broadband, there still wouldn’t be enough. So we have to think harder, and we have to take a step back and ask ourselves whether our commercial, cultural and personal lives have become so monoglot that we can afford to dedicate all of this scarce resource to one use? I have something to declare here, which is that many years ago I worked in Radio Astronomy and watched the HF and VHF bands become unusable for observation. Fortunately (maybe) Radio Astronomers had been making observations in this spectrum for many years before terrestrial applications of radio came to obscure the sky, but we’re now in the position where we can no longer see the sky with any sensitivity at frequencies of a few tens of MHz or lower. Imagine if you couldn’t see the night sky because of all the street lights? Ah, yes, you can’t, which is why most optical astronomy is now done from mountain tops and from space. So are we now going to elbow all the users of analogue spectrum like the radio microphone business and walkie-talkies to one side as we lurch towards this brave new digital wireless world. Well probably not, but we need to take care that the decisions are made not just on some notional economic value. There is a cultural legacy locked up in this UHF spectrum which we should not discard carelessly.
And then we come to LTE-U. I have one question for the EC, the GSMA and anyone else who’ll listen on this question. Why are we in Europe insisting on some namby-pamby listen-before-talk feature in LTE-U before we want to allow its use in unlicensed spectrum? What’s so special about European airwaves, 11n WiFi and 5GHz radar that means we need some provision that the FCC is happy to do without? If the EC is really interested in opening up spectrum for the competitive advantage of European business, then let it get out of the way of LTE-U.