SUMMARYThe DVB-S2 standard (ETSI: EN 302 307. Digital Video Broadcasting (DVB): second generation framing structure, channel coding and modulation systems for Broadcasting, Interactive Services, News Gathering and other broadband satellite applications (DVB-S2)) has been conceived for several satellite broadband applications: Television Broadcast Services, Interactive Services including Internet Access by consumers, Professional Applications such as Digital Satellite News Gathering (DSNG) and TV distribution, data trunking. This paper focuses on the profiles supporting interactive type of services, for which Adaptive Coding and Modulation (ACM) has been included in the new generation of the standard. Following the DVB-S2 specifications, a number of modem configurations and tools are made available for implementing ACM in interactive systems. However, the different approaches have important impacts on the design of the system architecture and of the scheduling/resource management algorithms. The aim of the present contribution is providing a first discussion on the critical issues at system and MAC level, which need to be addressed when implementing a DVB-S2 ACM system. A general introduction to ACM is also provided, as well as an illustration of the key elements included in the DVB-S2 standard for supporting physical layer adaptivity.