SIMULATION STUDY OF VSAT NETWORK MULTIACCESS PROTOCOLS/SWITCHING AND ADAPTIVE RETRANSMISSION STRATEGIES

Abstract

Analogous to earlier stages of development of the now mature local area network (LAN) technology, the VSAT industry is currently in the' process of selecting between a number of competing satellite channel sharing techniques. The selection is made on the basis of performance and implementation complexity and differ for each distinct traffic scenario. This report implements the simulation algorithms of various VSAT multiaccess techniques operating in realistic interactive transaction application environments and performance analysis is made based on simulation results. This report further includes the simulation investigation of adaptive retransmission policies 'viz, exponential, Mu-law, step and linear backoff. Joint optimization of steady state and dynamic performance of the contention channel used in VSAT data network is examined, by the application of traffic overload pulses. Lastly this report pursues a performance analysis, based on simulation, to compute the various packet loss, call blocking and packet delays of an on-board baseband non blocking (NxN) satellite switch, employed to route packets from uplink beams to downlink beams, in a multibeam satellite prioritized ISDN environment. A knockout priority blocking for traffic types viz, video, voice, file data and interactive data has been implemented, and a three-phase HOL contention resolution algorithm is shown competing with speed-up factor of the switch.