02075nas a2200181   4500008004100000245006100041210006000102260001800162300001600180520144600196100002101642700002301663700001901686700002001705700002201725700002401747856012201771       2013                        eng d00aFeedback-based Adaptation for Improved Power Consumption0 aFeedbackbased Adaptation for Improved Power Consumption  cMarch 25 - 28  a 562 - 568 3 aIn this paper we present a feedback-based
adaptation mechanism that adjusts the transmission power of
a wireless card on commodity PCs depending on the quality of
the connection. Our purpose is to manage the available power
in order to achieve lower power consumption without
negatively affecting the user?s perception of connection quality.
We based our implementation on an existing theoretical model
and focused on resolving problems and removing assumptions
which made it inefficient in real life implementation. The initial
model manages to minimize the power consumption in
networks with exactly two nodes. In this paper, we extend the
model to consider the possibility of the existence of a base
station, where any number of nodes can be connected. Our
objectives for the base station are to minimize the power
consumption and guarantee continuous connectivity for all
mobile nodes. We implement the adaptation mechanism for a
specific adapter with open sources drivers thus allowing
necessary modifications. We conduct a number of real world
experiments. The results indicate that power consumption can
be significantly reduced for nodes that are either almost
stationary or slowly moving (e.g. at walking speed), without
any significant increase in packet loss. The results are quite
important as nowadays mobile devices with limited battery life
time use tethering to become base stations for other devices
like in ad-hoc networks.1 aBouras, Christos1 aKapoulas, Vaggelis1 aStamos, Kostas1 aKioumourtzis, G1 aTavoularis, Nikos1 aStathopoulos, Nikos  uhttp://telematics.upatras.gr/telematics/publications/feedback-based-adaptation-improved-power-consumption?language=en