Claudio Sacchi, Assistant Professor
University of Trento, Dept. of Information Engineering & Computer Science, Disi, Italy
Since the early and visionary work published by A.C. Clarke on the journal ?Wireless World? in 1945, and for a long time, satellites were regarded as the only mean able at guaranteeing the ?global seamless coverage? over the terrestrial globe. Satellites allowed the worldwide TV broadcast and the intercontinental telephony service since mid of ?60s. Moreover, since almost 35 years, satellites enabled the global localization service (GPS) first to military and then to civil users. But, a lot of year has passed and the telecommunication market has become more and more aggressive and competitive. The recent enormous development of terrestrial networking, characterized by wired and wireless segments able at bearing broadband connectivity almost everywhere, trends to take away market shares from the satellites.
In this last ten years, the role of satellites in the commercial ICT panorama has been newly discussed. There is a general agreement about the fact that there is still room for satellite communications in the global TLC market. However, in order to compete with terrestrial networks, satellite operators and manufacturers should drastically decrease the cost per transmitted bit/sec. that is currently still too high. The simplest way to decrease the cost is to increase satellite throughput by exploiting larger frequency bandwidths without significantly increasing the power budget. The SATCOM research individuated some ?core? technologies that are currently available and may allow increasing the satellite link capacity at affordable cost: multibeam coverage with frequency reuse, use of high-spectrum efficiency waveforms, and use of higher frequency bands in the EHF domain, diversity combining, efficiency radio resource management and novel networking paradigms like Delay-Tolerant Networks (DTN).
Some very recent papers are speaking about ?multi-gigahertz? satellites or ?terabit? satellites. These terms are really exciting. But, as wisely entitled by J.D. Gayrard in his paper ?Terabit Satellite: Myth or Reality?? (published in SPACOMM Conference 2009), we should clearly separate the mythology from the reality or, in other words, science-fiction from science (even though, we should always take in mind that the first paper dealing with satellite communications was published by a science-fiction writer).
The seminar will show to the audience the latest technological developments about broadband satellite technologies, trying to insert them in the framework of the ?terabit? perspective. The accent will be posed in particular on efficient transmission, coding and multiple access management, considering also the perspective of near-future EHF domain exploitation with on-going research activities and some experimental activities (like Q-V band ALPHASAT ESA mission) that are already in their operative phase.