Globally harmonised spectrum is one of the most important factors behind strong mobile network economics, to enabling a huge ecosystem as well as international roaming.
The WRC-15 Conference took place during most of November, and sought to achieve a difficult balancing act between the spectrum requirements of different sectors such as mobile broadband, satellite and broadcasting. Two of its outcomes were important for small cells: the global harmonisation of the 3.5 GHz band for mobile broadband, and the decision to consider bands above 24 GHz for mobile broadband on the agenda for consideration by the next WRC, in 2019. The higher the frequency, the more the spectrum becomes the preserve of small cells, and both these decisions will help to open up more capacity, in turn driving new use cases, over the coming years.
Spectrum above 2.5 GHz – and particularly above 6 GHz – has not been considered optimal for mobile services because of its limitations in terms of range and penetration through walls. But small cells help overcome these restrictions, and as operators start to densify their networks in order to meet rising capacity needs, they will increasingly exploit small cell technologies
The 3.5 GHz band has already been a topic of interest to the small cell community. It has been licensed in some countries for fixed wireless, and in the US has Federal applications, but is generally very lightly deployed and a strong candidate to provide specific spectrum for small cells. The WRC-15 decision achieves global harmonisation, which will be essential to make the economies of scale work. ).
As John Giusti, chief regulatory officer of the GSMA, put it, such harmonisation is “key to driving the economies of scale needed to deliver low cost, ubiquitous mobile broadband to consumers around the globe”.
Of course, building commercial success on these foundations will depend on individual regulators. In the USA, the FCC is proposing a radical and rather complicated three-tiered approach to 3.5 GHz licensing, which protects Federal incumbents while offering both licensed and shared access options to wireless providers. In many other parts of the world, 3.5 GHz is already available and licensed, but, in some countries, these will need to be liberalised for mobile usage before this band can be used for mobile broadband.
But the WRC-15 decision is an important step in the right direction, and highlights how operator interest is creeping up the spectrum. This will be even clearer when it comes to 5G, and WRC-19 will be charged with decisions on harmonised bands for those technologies in bands between 24GHz and 86GHz. It is expected that 5G is expected to exploit the plentiful (and underused) spectrum in this frequency range as the only way to keep meeting the levels of demand for mobile data – hence the agenda item to explore potential bands above 24 GHz.
The issues around millimetre wave spectrum are not just about the economics of harmonization. There are many technical challenges to address too, , deciding on an air interface, working out how to integrate it into mass market devices and to aggregate it with lower bands.
However, the promise of all that untapped capacity is powerful, and it will only be harnessed to its maximum ability with small cells. All of this means a great deal of innovation and promise is still to come from our industry over the next decade.