ملخص: We develop an algorithm that allows an ARQ protocol to dynamically optimize the packet size based on estimates of the channel bit-error-rate. Our algorithm is particularly useful for wireless and satellite channels where the bit-error-rates tend to be relatively high and time variable. Our algorithm uses the acknowledgment history to make estimates of the channel bit-error-rate, based on which the optimal packet size can be chosen. We develop a Markov chain model for the analysis of the system, under static channel conditions, and show that the algorithm can achieve close to optimal performance using a history of just 10,000 bits. We also use the Gilbert–Elliott two-state Markov channel to model dynamic channel conditions. We show, through simulation, that the algorithm performs well even under rapidly changing channel conditions. Finally, we discuss a maximum likelihood approach for choosing the packet size, which performs almost optimally but is much easier to implement.

لغة: إنجليزية