A pull-based broadcast algorithm that considers timing constraints

There are many situations in which we need to incorporate real-time constraints in broadcasting systems for mobile environments. In this paper, we study broadcast scheduling strategies for pull-based broadcast with timing constraints in the form of deadlines. Unlike previously proposed scheduling algorithms for broadcast systems which aim to minimize the mean access time, our goal is to identify scheduling algorithms for broadcast systems that ensure requests meet their deadlines. We present a detailed study of the performance of traditional nonmobile real-time strategies and non-real-time mobile strategies, and demonstrate that traditional real-time algorithms do not always perform the best in a mobile environment. We propose a model of a pull-based real-time broadcast system and also propose an efficient scheduling algorithm, called Aggregated Critical Requests (ACR), which is designed for timely delivery of data to mobile clients.