Trade-Off between Spectrum Efficiency and Link Unavailability for Hierarchical Modulation in DVB-S2 Systems

Broadcasting systems have to deal with channel variability in order to offer the best spectrum efficiency to the receivers. However, the transmission parameters that optimize the spectrum efficiency generally leads to a large link unavailability. In this paper, we study the performance of hierarchical and non-hierarchical modulations in terms of spectrum efficiency and link unavailability for DVB-S2 systems. Our first contribution is the design of the hierarchical 16-APSK for the DVB-S2 standard. Then we introduce the link unavailability to compare the performance of hierarchical and non-hierarchical modulations in terms of spectrum efficiency and link unavailability. The results show that hierarchical modulation is a good alternative to non-hierarchical modulation for the DVB-S2 standard.