In this thesis we investigate the feasibility of using information overheard by wireless devicesudto reduce their overall energy consumption for communications. Specifically we investigate theudhypothesis "It is more efficient in terms of energy consumption to constrain the transmissionudpower based upon a combination of received signal strength with a minimally extended MAC,udthan to utilise an unchanged MAC and full power.".udWe investigate the hypothesis in the context of an ad hoc wireless network comprisingudof devices that use low power radio systems. We investigate two different low power radioudsystems, a standard 802.11 system and a custom low power radio device from Philips ResearchudLabs. We examine in detail the energy consumption of the Philips’ low power radio device inudits three modes of operation; transmission, reception and idle. From this, we propose a genericudframework for power measurement and illustrate the technique with a case study. Specifically,udthis technique identifies the three modes in a trace of the energy consumption of the low powerudradio device, and uses this information to accurately extract the consumption figures for theuddifferent modes of operation.udUsing our measurements and the energy consumption parameters for an 802.11 radio device,udwe examine in simulation the complex behaviour that emerges from the implementationudof an energy-aware system using a simple transmission power control algorithm that exploitsudoverheard MAC-level information to reduce device’s energy consumption. We evaluate thisudsimple algorithm using two radio systems and show that, in spite of the complexity, energyudsavings can be obtained using a scheme that takes advantage of overheard information.
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