After being used in communication systems for decades now, random access systems attract new attention, going far beyond providing a channel access for log-on, or signaling. The new paradigm of machine type of communications, where thousands of terminals sporadically transmit small data packets, raised the attention to the efficiency of the channel access policy. Orthogonal schemes that allow transmitters to communicate without the interference of the others, require communication overhead difficulty justified with huge population and small data packets. Random access is therefore, a suitable candidate to address these scenarios, thanks to its flexibility and simplicity, especially at the user terminal side. Recent enhancements leveraging on proactive replication of packets and interference cancellation has brought to drastic performance improvements compared to the well-known ALOHA and Slotted ALOHA (SA) protocols. After a first screening of the available access schemes suitable for machine type of communications via satellite, the most interesting access policy is selected for a first testbed implementation.
The objective of the project is the design, development and validation of key prototype elements for advanced return link (R/L) access techniques that can significantly improve the throughput and/or reduce the transmission delay with respect to currently adopted uplink access schemes. More specifically, the detailed objectives are to:
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