The effectiveness of battery-conserving protocols in wireless LANs

The idea that wireless LAN protocols can be customized so as to extend battery life in mobile devices has received considerable attention. We have previously reported experimentation and analysis of various methods for extending the lifetime of batteries in wireless devices. One area of our investigation has focused on the recovery effect and on a second battery effect, the rate capacity effect, and on their relative impact on the lifetime of Li-ion battery cells. Our experimental results support earlier non-experimental work that casts doubt on the efficacy of modifying protocols to take advantage of the recovery effect. In the work summarized here, we have augmented the previous work by comparing battery switching techniques, designed to exploit the recovery effect, to more conventional parallel cell connections which exploit the rate capacity effect. We show that the latter approach gives as good or better lifetime extension with simpler circuitry.