  We investigate the design of a broadcast system where the aim is to maximise
the throughput. This task is usually challenging due to the channel
variability. Modern satellite communications systems such as DVB-SH and DVB-S2
mainly rely on time sharing strategy to optimize throughput. They consider
hierarchical modulation but only for unequal error protection or backward
compatibility purposes. We propose in this article to combine time sharing and
hierarchical modulation together and show how this scheme can improve the
performance in terms of available rate. We present the gain on a simple channel
modeling the broadcasting area of a satellite. Our work is applied to the
DVB-SH standard, which considers hierarchical modulation as an optional
feature.
