Innovative thinking about how to make maximum use of limited spectrum resources was presented to an ATDI seminar.

Company managing director Cyprien de Cosson presented a study paper looking at the coexistence of new services at 5 GHz for a variety of purposes. “Currently, this spectrum is not allocated for such a purpose, but it is possible with close coordination that it could be used on a non-interference basis with primary services,” he told delegates.
 
The spectrum at the centre of the study is largely managed by the Civil Aviation
Authority and the Ministry of Defence for flight radionavigation services. Cyprien noted the allocations for this service are lightly used which provided the possibility for sharing. “However, immediately adjacent there are key radio astronomy assignments, which have significant protection requirements and may be limiting in terms of the spectrum that can be shared,” Cyprien said.

He told the seminar that using radio propagation planning tools for modelling, each service being protected could be taken in turn, to create a physical model in terms of test points representing applications of the services, after which the worst case coupling between the proposed service and those being protected could be computed. These results can be used to develop rules for coexistence including geographic restrictions, emissions limits, which can be implemented in a number of ways.

Cyprien comments: “We undertook this study to show the potential in spectrum sharing. I think this kind of modelling will figure large for everybody in Spectrum Management in the years to come.”

Earlier, the seminar, titled Spectrum Management: Can we co-exist without tears, heard from Julian McGougan, head of public policy and regulatory affairs at Arqiva, that “most spectrum is little used most of the time in most places.”

He said: “While the supply of spectrum may exceed demand in aggregate that may not be true just where you want access to it. The availability of thousands of empty houses in many parts of the country may not constrain your willingness to buy or rent any of the houses you like where you actually want to live. So it is with spectrum.”

Julian contended that the pressure on the spectrum is actually an artificial situation in that owners of large swathes of radio assets make little use of what they have – and he cited public sector users as a prime example of this – along with the fact that, in his view, Ofcom has commercially valuable spectrum which it has not yet auctioned.

The seminar was attended by a mix of military and civil radio users.