A Power-Variation Model for Sensor Node and the Impact against Life Time of Wireless Sensor Networks

We introduce manufacturing variation into a power model for a wireless sensor network node. Network protocols for the wireless sensor networks such as media access control and routing should be evaluated in terms of life time in a whole system. In fact, there exists power variation node by node due to the manufacturing variation. In the previous researches, however, this effect has not been investigated at all since it has been supposed that all nodes have a same power. In this paper, we develop a power model for a sensor node, in which we consider threshold-voltage variation derived from a manufacturing process. We take both a microprocessor and an RF part into account for the model, and implement it to QualNet in order to evaluate the impact against a life time of a wireless sensor network. The simulation results show that the conventional model has overestimated the life time longer than our model when nodes are randomly deployed. In contrast, if we make an optimum deployment of nodes by exploiting the power variation, the network life time is extended by 12.7% compared to the case of the conventional model.