Spreading-factor based addressing-tree protocol for ad-hoc wireless sensor networks

Tree-routing (TR) is a fundamental protocol most suited for a tree-like sensor network. Here, a sensor node deployed as leaf node senses the environmental phenomenon and forwards it to the sink node positioned as the root node by following a fixed parent-child path. This strategy prevents the network from flooding path search messages and saves bandwidth. The enhanced-tree-routing (ETR) protocol is an improvement to the TR protocol that uses a structured node address assignment scheme and considers neighbouring tables stored at each sensor node to find the shortest path to the sink. This requires minimum computation energy, storage and provides energy-efficient routing. In this paper the authors have proposed a spreading factor-based addressing (SFBA-tree) approach based on a non-blocking orthogonal vector spreading factor addressing technique, for the TR protocol and usage of movable sinks to eliminate excessive multi-hopping caused by the ETR protocol while discovering the shortest paths. Also, the authors have shown an SFBA-tree implementation to the ZigBee networks to prevent storage space and computation. The simulation result shows that the new scheme provides energy-efficient addressing and communication in a moderate size tree network.