Preemptive Scheduling for Multi-item Queries in On-Demand Data Broadcast

Scheduling for multi-item queries is a problem of practical importance in the field of data broadcast. Most previous works solve the problem under the pattern that at each broadcast moment, the server broadcasts a number of data items which constructs a broadcast cycle with fixed length. Within this pattern, if a query is not scheduled in the current cycle, it usually has to wait for quite a long time which prolongs the average access time. In this paper, we propose a preemptive scheduling method for multi-item queries in on-demand data broadcast. It breaks through the previous pattern. Simulation experiments show comparative improvements of average access time through our approach compared with the existing approaches.