Channel Forecast

Problem to solve and initial situation

In Satellite Communications broadband capacities needs are growing, which is met by use of higher frequency bands. Presently Ka-band frequencies are being established in the operational scenery, as an example Eutelsat's Ka-Sat shall be mentioned with its Tooway service 'fast internet everywhere'. The next step in even higher frequency bands will be use of Q- / V-band, which presently is investigated in research communities.

High frequency signals are heavily impaired by atmospheric phenomena like rain, snow, even by fog and clouds. The impairment cannot any longer simply be mitigated by providing a margin in transmit power, instead complex Fade Mitigation Techniques (FMT) are required. like Adaptive Code Modulation (ACM) etc.

A great advantage for the optimum employment of FMTs would be a short term forecasted knowledge on channel characteristics. This is exactly, what the proposed project is aiming, herein called Channel Forecast Software Tool (CFST). The value of the planned CFST has been discussed with the satellite operator Eutelsat, which they confirmed in a Letter of Support for the proposed project.

Planned goals and approaches (TRL Level Start-End)

The planned goals of the proposed project is the validated design for a CFST, providing short term channel characteristics forecasts. Although the individual steps for developing CFST seem to be straightforward, it is of considerable challenges to obtain reasonable reliability:

• Challenge 1: near real-time access to global weather data of sufficient spatial resolution and precision. The CFST would be of best value, when providing global coverage. Investigating access involves institutions like ECMWF, but also local meteorological services.
• Challenge 2: precise conversion of weather data to channel characteristics. Recommendations and models by the ITU serve as basis, but might to be improved.

Prototype modules for data access and conversion to channel characteristics thus will be provide channel characteristics forecasts, which will be validated by real-world measurements using the Alphasat TDP5 measurements.

Moreover CFST will give forecasts, which ground station in a site diversity configuration will be best to use.

TRL level at start may be rated as 2 'Technology concept and/or application formulated' and shall be brought to 4 'Component and/or breadboard validation in laboratory environment'.

Expected results and findings

The expected result is a validated design for CFST. Full implementation of a user-friendly operational CFST is beyond the frame of the herewith proposed activity. However prototype modules will allow a reliable validation. The whole activity will be oriented towards satellite operators' needs, with Eutelsat being ready to support the project by recommendations and feedback.

Coordinator

JOANNEUM RESEARCH Forschungsgesellschaft mbH

JOANNEUM RESEARCH Forschungsgesellschaft mbH
Leonhardstrasse 59
A-8010 Graz
Web: www.joanneum.at