AN ENERGY EFFICIENT BASE STATION TO NODE COMMUNICATION PROTOCOL FOR WIRELESS SENSOR NETWORKS

Abstract

A wireless sensor network consists of numerous tiny autonomous sensing nodes deployed across a wide geographical area. These sensor nodes self organize and establish radio communication links with the neighbouring nodes to form multi-hop routing paths to the central base station .(BS). Data sensed by these sensors is sent to base station for processing using low power transceivers. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible.. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of network. Several network layer protocols like LEACH, BCDCP, and PEDAP have proved very useful and efficient for nodes to base station communication. However, these centralized protocols have no explicit support for BS to node communication. In scenarios where BS to node communication is very frequent, the trivial solution of flooding may prove to be a very costly. We propose here M-way Search Tree Based Base-station to Node communication protocol (MSTBBN), a novel scheme to provide efficient base station to node communication for wireless sensor networks. MSTBBN can be used with any of the centralized underlying routing protocol (like LEACH-C, PEDAP) without any significant memory or message overhead. In any of the centralized routing protocol, when base station calculates the routing tree, MSTBBN can be used to assign each node a key (inspired from the concept of m-way search trees) which we term as KMSTBBN. Base station can now efficiently communicate with individual nodes with the help of assigned key. Our solution provides efficient communication with time complexity of 0(h) hops where h is the height of the BS-rooted- tree constructed by the underlying routing protocol. Efficiency of protocol is demonstrated using exhaustive simulations over ns-2.