Adaptive Go-Back-N an ARQ Protocol for a Tactical VSAT Network.

摘要

Tactical satellite networks require a Data Link Control (DLC) layer protocol to provide a virtual error-free communications link for point-to-point communications. It is of particular interest that the DLC protocol continues to operate under high bit error ratio conditions due to added noise caused by interference from other communications system or intentional jamming. Automatic Repeat Request (ARQ) protocols are the most commonly used DLC protocols in commercial systems. However, under high bit error ratio conditions, the throughput efficiency of an ARQ protocol decreases rapidly. To improve the throughput efficiency of ARQ protocols, some adaptive ARQ strategies have been theoretically analyzed. One particular ARQ protocol, and adaptive Go-Back-N (GBN) protocol, was selected for implementation in a tactical satellite network. The throughput efficiency of the adaptive GBN protocol was evaluated using data produced by a computer simulation. The simulation results for a three-stage adaptive GBN protocol was revealed a severe decrease in throughput efficiency when the bit error ratio was sufficient to cause frequent transitioning between the second and third stages. Under increasing bit error ratio conditions, a simulation of a two-stage adaptive GBN protocol demonstrated an appreciable improvement in throughput efficiency over a standard GBN protocol and the three-stage adaptive GBN protocol. Keywords: Satellite communication system; Adaptive protocol; Theses. (SDW)