Wireless Sensor Networks: Communication Mechanisms for Power-Aware Data Dissemination

A wireless sensor network is an ad hoc network consisting of numerous sensor devices (nodes). These nodes are linked via short-range ad hoc radio connections. Each node in such a network has a limited energy resource (battery), and each node operates unattended. Consequently, energy efficiency is an important design consideration for these networks. Inspired by the fact that in complex systems in nature each element follows simple rules in order to attain a common goal, we design energy efficient routing mechanisms that mimic this concept. The proposed unicast routing mechanism requires only local coordination of nodes to build a minimum cost topology (tree) on a network. Each node then uses power-aware selection to route data along a minimum cost route towards the target node. The proposed broadcast mechanism minimizes the number of rebroadcasting nodes by exploiting the broadcast nature of the wireless channel. We show that a simple local scheme executed at each node suffices to keep the number of retransmitting nodes close to a minimum number. Both communication mechanisms take into account the nodes’ limited energy resources, and thus extend the lifetimes of the sensor nodes. We evaluate the broadcast mechanism using simulation. We find that it exhibits good scalability and power-aware characteristics.