Applications
The DVB-S2 specification permits the use of 16APSK and 32APSK modes, allowing 16 and 32 different symbols respectively and are intended for mainly professional, semi-linear applications. They can be also used for broadcasting but they require a higher level of available C/N and an adoption of advanced pre-distortion methods in the uplink station in order to minimize the effect of transponder non-linearity.
Figure - Bit mapping into constellations - (see Ref.2)
Read more about this topic: Amplitude And Phase-shift Keying