An energy-efficient solution for packet-based transmissions with QoS constraints in the multibeam satellite downlink

This paper tackles the issue of boosting the capacity of xDSL networks in the presence of geographical gaps. An effective approach for such a kind of operating scenarios consists in exploiting the downlink of either legacy broadcast or advanced multibeam satellites for the delivering of packed-based traffic. This can be done by resorting to the data link layer protocol named Generic Stream Encapsulation which enables the transport of IP traffic (or any other packet oriented protocol) over the DVB-S2 uni-directional physical layer link. The solution presented in this paper consists first in the derivation of an adaptive coding and modulation (ACM) scheme for such an IP over DVB-S2 system, aimed at maximizing the “goodput” (GP), i.e., the offered layer-3 data rate, net of encapsulation overhead. To this aim, the look-up table for ACM is numerically derived by associating to any signal-to-noise-plus-interference ratio of the satellite downlink, the pair “modulation order/coding rate” yielding the highest value of GP. Then, in case of multibeam coverage, in order to manage the co-channel interference arising from beams exploiting the same band, an adaptive power control is also proposed. The goal of the latter is to maximize the energy-efficiency of the downlink satellite transmission while guaranteeing a given quality-of-service over each link in terms of minimum-GP constraint.