Analysis of Selective Retransmission Techniques for Differentially Encoded Data

This paper presents an analytical framework for the study of hybrid ARQ techniques aimed at the transmission of multimedia content with differential encoding. We propose a Markov model of a selective repeat hybrid ARQ transmission scheme, where we assume that packets have different properties in terms of size, information content, and retransmission limit, so as to capture the differential encoding which characterizes such multimedia data. We consider a non-zero round-trip time channel modeled through a discrete-time Markov chain. We provide an analytical tool for the evaluation of two main performance metrics, namely, throughput and goodput. The model is extremely flexible and allows evaluation of several channel conditions and comparison of different types of ARQ (plain ARQ, Type I and II hybrid ARQ). Our results can be used as an effective tool to define design guidelines of multimedia transmission systems and to understand their performance trends.