Node addressing schemes for scalable and fault tolerant routing in hierarchical WSNs

Most wireless sensor network deployments are 2-tiered where sensors form the leaves of the network and do not participate in the routing. A plot of the best path from each of the leaves to the sink reveals the network topology to be hierarchical in nature. The AODV routing algorithm was designed for a mesh network with highly mobile nodes and is not directly suitable for a hierarchical sensor network where the sensors and relays are predominantly static. The hierarchical routing as implemented by ZigBee´s C_skip does not support fault tolerance and has a restriction on the network depth. In this paper, we develop a node addressing methodology that merges the structure of a hierarchical tree with the flexibility of AODV. We show its completeness and develop three algorithms - deterministic, probabilistic and heuristic, based on our methodology. The performance of the algorithms against AODV is compared. Our simulation is made for two probability distributions of network formation - uniform and geometric.