A new hybrid broadcast scheduling algorithm for asymmetric communication systems: push and pull data based on optimal cut-off point

It is believed that broadcast is an efficient way to transmit data in an asymmetric communication system. Most of the previous work focused on either pnll-based or push-based scheduling. However, for systems with a very large number of data items, none of these schemes is efficient. We propose a novel scheduling algorithm which uses both pull- and ush-based schemes. In our approach,data items are divided into two disjoint sets: one consisting of more-popular items and the other of less-popular items. The items in the former set are broadcast by a push-based schedule, while those in the latter set by a pnll-based schedule. By optimally electing the cut-off point to distinguish these two sets, the new hybrid scheduling algorithm achieves a lower expected access time than other existing schedules.