Performance analysis of multiple access protocols for multimedia satellitenetworks

In this paper, several TDMA-based packet multiple access protocols are stud ied and evaluated in the geostationary satellite environment. The distribut ed queueing random access protocol, DQRAP, originally proposed for HFC netw orks is adapted to the satellite environment. Another protocol, the announc ed retransmission random access protocol, ARRA, proposed for wireless netwo rks is also studied. Both protocols are modeled and simulated in a VSAT net work context. We then propose a new protocol which combines the advantages of both studied schemes and is more adapted to interactive multimedia appli cations over satellite uplinks, The generalized retransmission announcement protocol, GRAP, regroups the immediate access by contention at low loads, and the reservation access at higher loads, to achieve a better channel eff iciency. An analytical model is proposed to calculate the channel throughpu t obtained by GRAP under different Loading conditions. Simulation results i llustrate an improved throughput/delay characteristics and a higher protoco l stability compared to both DQRAP and ARRA, Enhanced versions of the proto col are also proposed and evaluated to further improve its efficiency, with reasonable additional complexity.