SUMMARYThe ever-increasing demand for multimedia services from fixed and mobile users has motivated the scientific community, industries, and standardization fora to rethink the communication paradigm and the protocol architectures, resulting in an overall revolution of the Internet technologies. As satellite will play a pivotal role in this picture to exploit its broadcast and broadband capabilities; technical challenges come up in the integration of satellite and terrestrial networks. New paradigms based on the recent Future Internet studies findings have to be also applied to the satellite communications domain, with consequent implications on the design of the physical layer, in order for the satellite capacity to accommodate all of the offered services. This paper explores the various challenges arising during this process and draws a new concept of broadband satellite systems, tailored to the needs of fixed and mobile users.