AbstractThis thesis targets higher frequency satellite systems (Ku-band and above) that suffer from severe atmospheric impairments and require advanced techniques to compensate for the effects of rain attenuation.
Keeping a classical approach, based on a worst case sizing, results in fixed over-sizing of systems leading to reduced efficiency and unreasonable costs. It is therefore necessary that these systems include adaptive Fade Mitigation Techniques (FMTs) to counteract propagation impairments in real-time and use system resources efficiently.
The combination of the management of radio resources and the deployment of Fade Mitigation Techniques appears to be an outstanding challenge for Broadband Satellite Networks. DVB-RCS and DVB-S standards have not primarily been defmed considering the details of rain FMTs; they have to be adapted to support FMTs, so the study of efficient FMTs and their integration within the standards is necessary. Adaptive transmission techniques, such as Adaptive Coding and Modulation (ACM) , are mostly introduced as a way of achieving efficient Bandwidth on Demand (BoD). But they can also be a good framework for deploying FMTs and can provide high availabilities for powerful connections. Employing Burst Length Control (BLC) can be a useful extension of ACM to permit its dynamic range to be increased in the case of power-limited return channels, for which high -order modulation schemes cannot be used.
A design methodology of a combined FMT is proposed and presents the complex problem of system availability depending not only on the combined FMT performance, but also on the resource allocation scheme performance. A resource allocation protocol that incorporates FMT implementation within its dynamic capacity assignment strategy is developed and tested in the presence of bursty traffic when multiple links experience simultaneous fading.
|Date of Award||Jun 2008|
|Supervisor||Boris Gremont (Supervisor) & David Sanders (Supervisor)|