On battery conservation strategies for wireless protocols

Compared to other components of mobile devices, wireless network cards consume relatively high power. This makes wireless networking components a prime focal point for efforts to extend the lifetime of batteries that power mobile devices. It is widely recognized that battery lifetime can be extended by adjusting discharge timing and profiles and a large volume of work has been done on the subject of tailoring wireless protocols to exploit this fact. In particular, much attention has been devoted to protocols that produce pulsed power profiles rather than constant loads. However, recent findings based on analytical models have called into question the efficacy of these approaches versus other power-reduction techniques. In this paper, we report the results of experiments that we conducted to test the relative potential of two strategies for shaping protocols to extend battery lifetime. We show how our experimental results support the concept that battery-efficient protocol designs should consider other load profile factors in addition to pulse characteristics.