Center for Embedded Network Sensing

The multicast reliability problem has been studied extensively in the wired internet domain, and, more recently, in wireless and ad-hoc networks as well. In the context of wireless sensor networks, comprised of small, low power and resource-constrained nodes that interact with the physical environment, it remains an active research area. A special case of multicast reliability that is of particular interest in the sensor network domain is code distribution. The ability to add new functionality or perform software maintenance without having to physically reach each individual node is an important piece of a sensor network infrastructure. It becomes critical as sensor networks mature and move toward larger deployment sizes. We present eemoap, an energy-efficient multihop over the air programming mechanism. We discuss the design goals, choices and optimizations for building an efficient code distribution scheme on mica2 motes. The mechanism is evaluated in simulation as well as in an actual mote implementation.