DiMo: distributed node monitoring in wireless sensor networks

Safety-critical wireless sensor networks, such as a distributed fire- or burglar-alarm system, require that all sensor nodes are up and functional. If an event is triggered on a node, this information must be forwarded immediately to the sink, without setting up a route on demand or having to find an alternate route in case of a node or link failure. Therefore, failures of nodes must be known at all times and in case of a detected failure, an immediate notification must be sent to the network operator. There is usually a bounded time limit, e.g., five minutes, for the system to report network or node failure. This paper presents DiMo, a distributed and scalable solution for monitoring the nodes and the topology, along with a redundant topology for increased robustness. Compared to existing solutions, which traditionally assume a continuous data-flow from all nodes in the network, DiMo observes the nodes and the topology locally. DiMo only reports to the sink if a node is potentially failed, which greatly reduces the message overhead and energy consumption. DiMo timely reports failed nodes and % greatly minimizes the false-positive rate and energy consumption compared with other prominent solutions for node monitoring.