Link layer driver architecture for unified radio power management in wireless sensor networks

Wireless Sensor Networks (WSNs) represent a new generation of networked embedded systems that must achieve long lifetimes on scarce amounts of energy. Since radio communication accounts for the primary source of power drain in these networks, a large number of different radio power management protocols have been proposed. However, the lack of operating system support for flexibly integrating them with a diverse set of applications and network platforms has made them difficult to use. This article focuses on providing link layer support toward realizing a unified power management architecture (UPMA) for WSNs. In contrast to existing monolithic approaches, we provide (i) a set of standard interfaces that separate link layer power management protocols from common MAC level functionality, (ii) an architectural framework that allows applications to easily swap out different power-management protocols depending on its needs, and (iii) a mechanism for coordinating multiple applications with different power management requirements. We have implemented our approach on both the Mica2 and Telosb radio drivers in TinyOS-2.0, the second generation of the de facto standard operating system for WSNs. Microbenchmark results show that our approach can coordinate the power-management requirements of multiple applications in a platform independent fashion while incurring negligible overhead.