Recently on the Telegraph online, I saw an article on the next round of spectrum licensing in the UK. The UK Government has committed to release 500MHz of public sector spectrum by 2020, and this move is part of that. There are two bands being released – 40MHz at 2.35 – 2.39GHz, which I think has to be part of TDD Band 40, and 150MHz above 3.41GHz which could be part of TDD band 40, or conceivably part of FDD band 22. Ip.access sells licensed radio kit, right? More licensed spectrum equals more sales of radios to use it, right? So we should be happy, right? Well, maybe. Read on, dear reader, read on…
One of the massive trends in the industry now is towards RAN sharing. We’ve seen tower-sharing agreements turn into complete corporate mergers, and the predominant focus in mobile operators now is in managing the cost of the delivered bit. With the huge increase in the volume of data being delivered, continuing to grow at CAGR over 50%, this focus is understandable. Tower sharing is one solution. Distributed antenna (DAS) solutions are another, for larger indoor and campus deployments, where each operator bellies up to the DAS with their favourite basestation and shares the antenna path with their competitors. These solutions are big plays. The capex is big, and the cost of change is big. So they only work above a certain critical size of deployment – usually several hundred thousand or a million square feet. For small cells, the RAN sharing story has always been a bit more complex. There is a 3GPP feature called MOCN which is an ideal technical solution for allowing operators to share their RAN infrastructure, but as one industry colleague of mine put it last week, it’s a great solution “if you’re an engineer”. Phew, bit below the belt there, I thought, but actually it’s a fair comment. There’s nothing in the feature itself which says how one operator can make money by allowing its competitors access to its spectrum, nor how they can apply policy to the sharing arrangement. It’s all been left as something of an “exercise for the reader” which is code for “ain’t gonna happen”. And indeed the number of MOCN deployments in the world is a small handful. Even if you were a three-toed sloth, you’d still only need one foot to count them all.
There is another model on the horizon. LTE-U.
In LTE-U, or at least one version of LTE-U, a carrier in licensed spectrum is aggregated with another carrier in unlicensed spectrum. So, when a mobile operator needs to multiply up its capacity in a certain area, it can shift its users on to the unlicensed carrier, and just carry more traffic, to the delight of its subscribers, and its shareholders. When people talk about LTE-U they’re normally talking about an unlicensed carrier in 5GHz spectrum – sharing the same spectrum that WiFi 802.11n or 11ac uses. There’s so much spectrum up there that the capacity gains can be enormous, and there’s plenty to go around – up to 700MHz in some areas. The fact it’s unlicensed means that operators can set the carrier frequency freely within the band to avoid existing WiFi APs and other military radar stuff that still lingers up there, and still have room for multiple streaming HD videos per user. There are some regulatory and standardisation hurdles still to be overcome, it’s true, and the handsets don’t yet exist to exploit that spectrum in LTE.
So, sounds a long way off. Or is it? What does that look like in the light of Ofcom’s recent announcement? Band 40 (at 2.3GHz) is already in use in Asia. Its use is already standardised by 3GPP. The handsets exist already to use this spectrum and they’re in wide circulation. What would happen if Ofcom had adopted an unlicensed model for this spectrum? Lots of good things. Existing operators would have been able to deploy infrastructure (using RAN sharing techniques as I described earlier) to give the optimum network performance for their customers. It could have become an early test bed for the alternate LTE-U model, where new operators deploy infrastructure, like WiFI APs, but using LTE solely in the unlicensed band. All of the great quality of service, small packet performance, high user density, high mobility performance of LTE would have been available there, in an instant, using phones that are already on the market. By making the whole of the spectrum available as a single 40MHz block, the freedom of configuration to avoid interference would have been maximised, and by trunking the whole spectrum into a 40MHz block instead of dividing it up into separately licensable 5MHz blocks, the capacity and quality of the new spectrum would be maximised, to the benefit of all – operators and end-users alike.
So why has Ofcom licensed this spectrum then, to continue the present model, even though the world needs RAN sharing in small cells? If mobile broadband is the imperative, and it is, then why choose a model that divides the spectrum up into sub-optimal, inflexible chunks? Isn’t it time to set the scene for an entrepreneurial new generation of players use the spectrum as well, and see who wins out on a level playing field?