Characterization and modelling of propagation effects in 20-50 Ghz Band

Project abstract

The architecture of the new satellite communication systems relies on the full exploitation of the 20/30 and 40/50 GHz frequency bands, to provide broadband services to a large number of earth terminals all over the world.
The adoption of higher frequency bands has a major impact on atmospheric propagation related issues in the system design.
Due to the greater relevance of the various propagation effects with respect to lower frequencies, the accuracy and the completeness of propagation models results a critical issue even for the assessment of system feasibility. In addition to the usual link-budget evaluation, propagation models for advanced satellite systems are employed also for other analyses.
Actually, the design of Fade Mitigation Techniques (FMT) relies on accurate propagation models and the analysis of system performances can be carried out by using propagation channel simulators. Moreover, concerning the inputs to propagation models (statistics of rain intensity, water vapour and liquid water total content, etc.), their accuracy, spatial resolution, statistical stability and global validity has been greatly increased by assimilation of remote sensing (RS) data and products of Numerical Weather Prediction (NWP) to derive world wide maps of climatological parameters.
The main objectives of the study were:

• the identification of the requirements of tropospheric effects modelling for advanced Satellite Communication Systems design;
• the critical review of propagation experiments (completed in the past, currently on going or planned in the near future), of the radio climatological databases useful for propagation modelling and of tropospheric attenuation models;
• the calculation of new radio climatological databases (with better accuracy and spatial and temporal resolution) useful for propagation modelling;
• the development of new models for tropospheric propagation effects with better accuracy, a wider applicability as for frequency and probability ranges, and better climatological description; testing activity devoted to the assessment of the models’ accuracy.

The activity was finalized; the final report have been delivered to (and accepted by) ESA.

Project results

The main results of the activity have been:

• critical review of the satellite propagation experiments and propagation models;
• assembling of databases with statistics of propagation experiments;
• calculation of new global maps (new parameters, new statistics, greater accuracy and better spatial resolution) of climatological parameters useful for tropospheric propagation modelling;
• development of new models (greater accuracy, new effects, new statistics) for tropospheric propagation effects;
• models performance evaluation.

The results of the activity have been already presented at ESA Propagation Workshop 2005 "Radiowave Propagation Modelling and Measurements for SatCom and SatNav Systems" (Novembre 23-25, 2005, ESA-ESTEC, Noordwijk, The Netherlands) and, up to now, have generated 9 conference contributions and one journal paper.