Scheduling real-time requests in on-demand broadcast environments

On-demand broadcast is an effective approach to disseminating real-time data to mobile clients in mobile environments. Recent studies mostly assume that clients request only a single data item. This assumption may not sufficiently support the increasingly sophisticated real-time applications in mobile environments. In this paper, we present three on-demand broadcast algorithms to cater for multi-item requests with timing constraints. We argue for the case of aggregation of data requests to minimize, the broadcast bandwidth and deadline miss rate. The three algorithms try to exploit different properties of system characteristics for aggregation. Our simulation results show that a good aggregation algorithm should consider both data overlapping of client requests and their urgency.