User Terminal Wideband Modem for Very High Throughput Satellites

International audienc

Adaptive coding and modulation for satellite broadband networks: From theory to practice

This paper presents the detailed design and the key system performance results of a comprehensive laboratory demonstrator for it broadband Ka-band multi-beam satellite system exploiting the new DVB-S2 standard with adaptive coding and modulation (ACM). This complete demonstrator allows ill-depth verification and optimization of the ACM techniques applied to large satellite broadband networks, as well as complementing and confirming the more theoretical or simulation-based findings published so far. It is demonstrated that few ACM configurations (in terms of modulation and coding) are able to efficiently cope with a typical Ka-band multi-beam satellite system with negligible capacity loss. It is also demonstrated that the exploitation of ACM thresholds with hysteresis represents the most reliable way to adapt the physical layer configuration to the spatial and time variability of the channel conditions while avoiding too many physical layer configuration changes. Simple ACM adaptation techniques, readily implementable over large-scale networks, are shown to perform very well, fulfilling the target packet-error rate requirements even in the presence of deep fading conditions. The impact of carrier phase noise and satellite nonlinearity has also been measured