A number of novel physical layer techniques, and in particular adaptive coding and modulation (ACM) combined with high order modulations, have shown the potential to significantly improve throughput of current return link (RL) broadband access satellite systems. However, their introduction shall be complemented by novel concepts at MAC and network layer, which aim at increasing flexibility and maximizing actual achieved system efficiency, In this paper a novel frame and burst format is proposed, capable of ensuring high overall efficiency combined with radio resource management (RRM) simplicity. A comprehensive cross-layer optimization is carried out through simulation and numerical assessment in order to optimize burst lengths taking into account physical layer performances and network traffic profiles. Moreover, a novel encapsulation protocol (generic stream encapsulation-GSE) is considered to further improve IP transport efficiency.

Through a rapid survey of the architecture of low-density parity-check (LDPC) decoders, this paper proposes a general framework to describe and compare the LDPC decoder architectures. A set of parameters makes it possible to classify the scheduling of iterative decoders, memory organization, and type of check-node processors and variable-node processors. Using the proposed framework, an efficient generic architecture for nonflooding schedules is also given.