WRC 2027 Agenda Item Details

This agenda item considers possible revisions of sharing conditions in the frequency band 13.75-14 GHz to allow the use of uplink fixed-satellite service earth stations with smaller antenna sizes.

The ITU-R is invited to study possible changes to the minimum antenna size and associated power limitations to protect the services as stipulated in Nos 5.502 and 5.303.

WRC-27 is invited to consider the results of the above studies and take necessary actions, as appropriate.

This is not the first time this frequency band and sharing scenario has been discussed in the ITU-R - see this link to the previous analysis of the agenda for WRC-2003. The results of this study cycle was encapsulated in 5.502 and 5.503 which defines a minimum antenna diameter of 4.5m for non-GSO satellite systems and average eirp limits. In addition there are PFD thresholds to be met along coastlines or country borders. These constraints were designed to protect stations in the radiolocation or radionavigation services from harmful interference.

These limits, in particular the minimum antenna diameter of 4.5m for non-GSO systems, are increasingly seen as constraining and not technologically neutral between GSO and non-GSO.

As we said back in 2000 for the original agenda item, Visualyse can model all the services to be considered in this JTG including FSS (both GSO and non-GSO) and radiolocation services, and hence calculate interference levels to allow a trade off of parameters such as minimum dish size and EIRP levels. Indeed, a lot of the studies during that WRC cycle were undertaken using Visualyse, and similar studies could be done in this cycle.

We can undertake studies including analysis of sharing between the services covered by this agenda item, and identify suitable system characteristics and sharing criteria, and provide contributions and representation at ITU-R Working Parties. Using our in house Visualyse Professional we can quickly model a very wide range of systems, services and scenarios. We have can model GSO and non-GSO FSS systems and create sharing scenarios with stations in the radiolocation and radionavigation services, particularly given our experience supporting the studies in the cycle leading up to WRC-2003.