Lifetime Optimization for Wireless Sensor Networks Using the Nonlinear Battery Current Effect

One of the design challenges of wireless sensor networks is the tradeoff between network operation time and network coverage. Recent studies reveal that the useable battery capacity drops faster at a higher discharge current in a nonlinear fashion. To take advantage of this battery current effect, in this paper we explore a new sensor node deployment scheme to prolong the entire sensor network lifetime as well as each individual sensor node. The key idea of the proposed scheme is to assign a sensor node having higher traffic load to adopt lower transmission power level. In this way, batteries of all nodes in a given area are discharged at the same current, thus they are depleted at the same time. Extensive simulations have conducted to evaluate the performance of the proposed sensor node deployment scheme. Compared with peer work on heterogeneous deployment, the useable battery capacity by using the proposed scheme can be improved by 26.67%, and the operating time per sensor node can be enhanced by 20.95%. Furthermore, the proposed deployment scheme can reduce the number of sensor nodes required to cover the given area, leading to a significant reduction of deployment cost.