A power-aware scheduler for streaming multimedia clients

by 1981- Gundlach, Michael

Mobile computers consume significant amounts of energy when receiving streamed multimedia data. The wireless network interface card (WNIC) consumes a large portion of this energy. One way to reduce the energy consumed is to transmit the packets to clients in a predictable fashion. Specifically, the packets can be sent in bursts to clients, who can then switch to a lower power sleep state between bursts. This technique is especially effective when the bandwidth of a multimedia stream is small. This paper investigates techniques for saving energy in a multiple-client scenario, where clients may be either (1) viewing streaming multimedia or (2) receiving background (e.g., web) data. Given the real-time requirements of multimedia traffic, we differentiate network traffic into two types: multimedia and background. We then generate different global schedules for multimedia packets and background packets. Several difficulties arise with multiple clients, including delays, droughts and bandwidth limitations. Despite this, multimedia clients using our schedule save significant energy with few missed packets, while general clients achieve reasonable end-to-end latency. For example, our schedule saves over 90% of the energy for ten multimedia clients viewing 56kbps video streams. With an additional 220kbps of web traffic, end-to-end latency averages 32 ms, while multimedia clients save 86.9%. Index words: multimedia, scheduling, energy, power-aware, wireless networking A Power-Aware Scheduler For Streaming Multimedia Clients by Michael Gundlach B.S., The University of Georgia, 2002 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree Master of Science Athens, Georgia 2002 c? 2002 Michael Gundlach All Rights Reserved A Power-Aware Scheduler For Streaming Multimedia Clients by Michael Gundlach Approved: Major Professor: David K. Lowenthal Committee: Scott A. Watterson John A. Miller Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia December 2002