Wireless LAN (WLAN) interfaces are responsible for a significant fraction of the total energy consumed by a large class of mobile client devices. WLAN interfaces have power saving features which enable substantial energy reductions during long idle intervals. However, during periods of activity, when data transfers occur, the nature of the network traffic is hard to predict and this prevents the network interface from fully utilizing the power-save features between packet receptions. This paper introduces a web proxy architecture designed to enable further reductions in the energy consumed by WLAN interfaces. The proxy modulates the traffic directed to the wireless client into alternating intervals of high and no communication. The modulation takes into account the semantics of the web traffic and the configuration of the client’s WLAN interface. As a result, the interface spends more time in power-save mode and less time in active mode. Initial experiments show energy reductions of 13% and higher on popular web sites such as CNN and NY Times, and up to 56% when downloading large objects. The architecture does not require any modifications of the client or server applications.
By: Marcel C. Rosu, C. Michael Olsen, Chandrasekhar Narayanaswami, Annie Luo
Published in: RC23119 in 2003
LIMITED DISTRIBUTION NOTICE:
This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.
Questions about this service can be mailed to reports@us.ibm.com .