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23 September 2019

Starting gun sounds for CBRS, sparking open spectrum initiatives elsewhere

Spectrum is, of course, the lifeblood of wireless networks, and therefore has always been the subject of regulation, fierce competition and often high costs. But in the wireless broadband world, it fitted neatly into a bilateral structure of long term exclusive licenses for cellular, and completely unlicensed for WiFi and other technologies. While MNOs might use a mixture of the two types of technology, their power rested with their licenses, and their 3GPP networks lived only in those licensed bands.

Then LTE moved into unlicensed spectrum, notably 5 GHz; and the boundaries between licensed and unlicensed networks and operators blurred further with moves to open up cellular spectrum and make it available and affordable to a wider base of organizations, including enterprises and private or neutral host providers. The trailblazing scheme in that regard is the USA’s CBRS, though its general access portion currently relates only to 4G. The real disruption will come when 5G can be deployed in unlicensed or shared spectrum (that will be supported in the next release of 3GPP standards); and when spectrum sharing becomes fully dynamic. That will enable large numbers of service providers to harness 5G to support a huge range of use cases and industries.

Unless this outcome is achieved, 5G will not fulfil its socio-economic promises, or even deliver a robust business model for most MNOs. The first steps are relatively small – CBRS is a fascinating breakthrough, but its commercial impact is yet to be tested and it may still end up providing more, lower cost spectrum for established MNOs and cablecos, rather than blowing the deployment chain open, as is necessary to meet the diverse needs and cost bases of cities, industries and transport.

Even more cautious is the UK’s first step towards enabling industrial and private networks – there is no unlicensed or dynamic aspect to its new local and shared access rules, but they are certainly a step in the right direction, and quite a radical leap for regulator Ofcom, which has been conservative on spectrum change in recent years. Like other regulators, it has come under pressure from its government, anxious to see its ambitious 5G strategies being realistic – which will require participation from more than just a small clique of MNOs.

Spectrum and technology are moving targets too. The blueprint for shared spectrum and neutral host or enterprise networks is in the WiFi world, and ‘5G’ will consist of a combination of the 3GPP standards and WiFi 6, whose own certification is starting soon. This is why a WiFi organization, Wireless Broadband Alliance, has published its second major paper in conjunction with a cellular body, NGMN Alliance, to push the cause of convergence rather than competition between the two platforms.

And as regulators, operators and vendors consider what 5G will really look like, there is already work on pushing mobile communications into new spectrum bands, particularly at very high frequencies – hence the publication of the first major white paper setting out the path to ‘6G’, whose main difference from 5G currently centers on ‘terahertz’ spectrum.