The Relationship between Sensor Networks Performance and the Number of Reporting Nodes

Energy conservation is a primary concern in wireless sensor networks due to the limited capacity of the sensor nodes' batteries. In this paper, we study the relationship between sensor networks performance, particularly its lifetime, and the number of reporting nodes N by using both analytical and simulation approaches. We first show that decreasing N increases considerably the network lifetime. Moreover, we demonstrate that the average time required to report an event is a convex function of N. Based on these results, and as a main contribution, we prove that the optimal number of reporting nodes enabling the shortest latency to report reliably an event does not really lead to the most efficient way of energy consumption. In this paper, we analyze the tradeoff between these two requirements. We provide a simple methodology to achieve this tradeoff which is specific to each sensor application, depending on its particular needs.