Scheduling data broadcast in asymmetric communication environments

With the increasing popularity of portable wireless computers, mechanisms t o efficiently transmit information to wireless clients are of significant i nterest. The environment under consideration is asymmetric in that the info rmation server has much more bandwidth available, as compared to the client s. In such environments, often it is not possible (or not desirable) for th e clients to send explicit requests to the server. It has been proposed tha t in such systems the server should broadcast the data periodically. One ch allenge in implementing this solution is to determine the schedule for broa dcasting the data, such that the wait encountered by the clients is minimiz ed. A broadcast schedule determines what is broadcast by the server and whe n. In this paper, we present algorithms for determining broadcast schedules that minimize the wait time. Broadcast scheduling algorithms for environme nts subject to errors, and systems where different clients may listen to di fferent number of broadcast channels are also considered. Performance evalu ation results are presented to demonstrate that our algorithms perform well .