Roke Manor Research Commissioned to Review Bandsharing Solutions

Roke Manor Research has considerable radio communication experience working in the defence, civil communications, naval Maritime and aeronautical sectors. This led it to being chosen as key consultant to contribute its expertise on band sharing for the Cave Audit.

Roke examined the theoretical aspects of bandsharing to see what was technically possible and economically viable - in order to make more efficient use of the spectrum. As part of its investigation it looked at how it could prove spectral coexistence theories.

Following the publication of the review, Roke has now been asked to participate in trials to prove the concepts it suggested.

The review presented a number of methods for sharing spectrum between ATC radar and a new wireless communications system in the S-band in the 10-20 year frame. Two approaches for bandsharing: integrated sharing and spatial sharing have been considered.

In order to facilitate and optimise this sharing scheme, it will be necessary to improve the performance of the radar stations. In particular, it will be highly desirable to reduce the transmit power for a given range as well as improving the immunity to interference.

The need to develop the new radar and communications systems jointly has been highlighted. In particular, any anticipated de-sensitisation of the radar by communications generated interference must be factored into the radar link budget from the start. Issues around bandsharing with military and maritime radars were considered including the desirability of designing the communications system to generate ad-hoc exclusions zones at will.

Because of the safety critical nature of ATC radar, examination of failure mechanisms that could affect radar performance was considered. Some failure modes were also considered and their possible solution identified. The parallel generation of two new systems to share spectrum, particularly where one is safety critical, represents a unique requirement. To meet this, a multi-stage route to development and deployment was discussed.

The report concluded there is enough potential in a spatial approach to bandsharing between radar and communications in the S-band, particularly given the potential economic benefits, to justify further work in this area. The next stage would be a detailed feasibility study examining the link and interference budgets for an initial putative combined system concept.