Spectrum for UAS communications

07 November 2014

Colin Long, Paul Briggs, Simon Phippard

An essential input

Radio frequency spectrum is crucial to the future development of strategic and commercial UAS. Without it, growth of the UAS industry – expected to be exponential – will be badly constrained.

In the UK, as in most other countries, spectrum for aeronautical/safety-critical purposes is assigned by the civil aviation regulator, the CAA, on behalf of Ofcom, the communications regulator. On the other hand spectrum for payload communications, such as commercial applications exploiting the UAS capabilities, is exclusively in the competence of Ofcom.

Only a marginal amount of spectrum has been earmarked for UAS, and that only for 'safe operation', i.e. command and control and non-payload communications ('CNPC'). Internationally, the use of frequency bands allocated to the Fixed Satellite Service (FSS) is also being considered for CNPC/Beyond Line of Sight applications. That issue is on the agenda for the International Telecommunication Union's quadrennial World Radio Conference in 2015. It is not, however, currently supported by ICAO and the use of FSS in this way is still the subject of study by the ITU.

As commercial applications for UAS emerge, suitable frequency bands must be found for real-time communication of the payload data collected by UAS operations. Compared to CNPC uses, even less thought has been given to this potential demand: there are many competing requirements for spectrum (satellite, terrestrial fixed and mobile use) and not all of the useable bands may be available. So far no specific frequencies bands have been specifically assigned or even identified as a potential priority for UAS payload communications, terrestrial or satellite. Providers of satellite uplinks and downlinks may be prepared to make available their own spectrum capacity for payload as well as CNPC purposes, but payload should not use aeronautical assigned spectrum and vice versa.

Spectrum policy

The UK Government is currently looking at the value of alternative uses of spectrum from a broad public policy perspective; its conclusions are anticipated in 2015. The governing principle of this review, however, will be that spectrum bands should be assigned to new users according to what will deliver the best value to the UK. More concerning for the industry, in 2013 Ofcom identified aeronautical uses as 'low' in significance and urgency, even though important public interest uses could arise from UAS development.

Call for Action

We recommend the UAS industry, not just UK-based but internationally, should seriously consider the implications of these challenges of securing suitable spectrum and the relative lack of priority the issue is receiving. The ITU, Ofcom and other leading regulators will likely only take note if a concerted effort is made to produce the evidence and the demand for spectrum to enable this burgeoning industry.