Application-Specific Power Management for Wireless Networks

Matthias Faerber

Advisor: Andreas Weißel, Dr.-Ing. F. Bellosa

Registered as Studienarbeit SA-I4-2004-02 , January 19 2004

[Abstract] [Full Paper (pdf) , 264 kB]

In recent years computer networks have gained importance in many fields. After the success of wired networks and the internet, radio based wireless networks are spreading. In many cases wireless networks are used when it is impossible to connect the computer to a network using a cable or it is just uncomfortable. This not only applies to network cables but also to power cables and so most devices are battery powered.

Wireless network adapters that are using the IEEE 802.11b standard are already equipped with a power management mode. In this power management mode the card continously changes between a sleep and an awake state. The sleeping interval can be altered by setting the so called beacon interval.

This work examines how network applications can be identified only with information available at the network layer. It is shown that statistical information derived from the linux kernel can be used to characterize and identify applications. For a set of applications such profiles are developed and explained.

Based on these profiles an algorithm is provided that is capable of detecting applications during their runtime and adjust the beacon interval of the IEEE Standard. Thus the static behavior of the power management mode it changed into a dynamic one. The algorithm considers both application performance and energy conumption and sets the power management to an user-defined trade-off between both.

The results of the characterization algorithm are evaluated in two tests. First offline tests are used to analyze the detection rates for one application alone. Second, online tests are used to analyze the delay between the start of an application and its detection and the impact of false characterizations.