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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

The paper deals with an analysis of very High Throughput Satellite (VHTS) systems employing optical feeder links. To do so, a fixed set of user requirements is selected that allows for different optical feeder link options to be compared and evaluated on a common basis. The main system aspects are discussed and a rough assessment of the payload resources in terms of mass, power and dissipated power required for each is provided. This exercise reveals important trade-offs and new research avenues for the optical communications community.

The paper deals with an analysis of Very High Throughput Satellite (VHTS) systems employing optical feeder links. As the capacities of newly announced next generation VHTS systems are exceeding the Terabit/s barrier, a large amount of investment needs to be directed not only to the space segment (as was the case traditionally), but also to the ground segment in support of the feeder links. To reduce this investment, satellite operators are reviewing various options and technologies for the feeder links, among which optical feeder links [1]. In this paper, different approaches are analysed for ground segment networks relying on Optical Ground Stations (OGS), exploring the concept of smart gateway diversity with N active OGS and P redundant ones, like is currently done in VHTS systems with RF feeder links. OGS locations are assessed in terms of aggregate availability and total cost for the satellite operator, which is an essential element for the viability of the VHTS system. Different options are assessed for the distribution of OGS gateway processing functions (local at OGS or centralised), and for their interconnection. The main technical challenges are discussed, identifying which technologies will be required for an operational VHTS system with OGS.

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