A communication paradigm for hybrid sensor/actuator networks

The paper investigates an anycast communication paradigm for a hybrid sensor/actuator network, consisting of both resource-rich and resource-impoverished devices. The key idea is to exploit the capabilities of resource-rich devices (called micro-servers) to reduce the communication burden on smaller sensor nodes which are energy, bandwidth and memory constrained. The goal is to deliver sensor data to the nearest micro-server, which can (i) store it, (ii) forward it to other micro-servers using out-of-band communication, or (iii) perform the desired actuation. Our approach is to construct an anycast tree rooted at each potential event source, which micro-servers can dynamically join and leave. Our anycast mechanism is self-organizing, distributed, robust, scalable, and incurs very little overhead. Simulations using ns-2 show that our anycast mechanism can reduce network energy consumption by more than 50%, both the mean end-to-end latency of the transmission and the mean number of transmissions by more than 50%, and achieves 99% data delivery rate for low and moderate micro-server mobility rate.