Abstract: In a large-scale Wireless Sensor Network (WSN), the nodes closer to the single sink node use up their energy more quickly than others because of relaying more packets so that the network is invalid rapidly. In order to elongate the network lifetime, it is required to deduce the hops from sensor node to sink node. An efficient method is to deploy multiple sink nodes instead of single one. Therefore, it needs to be considered that how many sink nodes should be deployed on minimizing network cost and maximizing network lifetime. A network lifetime model and a cost model were proposed in WSN with multiple sink nodes and a new method was presented to determine the optimal number of sink nodes by computing the Ratio of Lifetime to Cost (RLC). The theoretical studies show that the number of sink nodes is related to the cost of sensor nodes and sink nodes, the network scale, the number of critical sensor nodes and the transmission power of sensor node. The simulation results prove the theoretical conclusion.

Key words: Wireless Sensor Network (WSN), multiple sink node, network lifetime, network cost, energy model

摘要： 大规模无线传感器网络(WSN)环境下，当网络结构采用单一的sink节点时，容易造成sink节点周围的普通传感节点因为转发大量其他节点的数据，迅速消耗掉自身能量而使网络失效。为了延长网络寿命，需要降低传感节点到sink节点的跳数,而采用多sink结构是一个有效的方法。为此，需要考虑一定规模的网络中，应该布置多少sink节点，才能使得网络寿命最大化的同时网络成本最低。基于栅格网络结构，提出了多sink节点下的网络寿命模型和网络成本模型，并采用一种新颖的方法计算最大网络寿命成本比(RLC)，推导出了保证网络寿命最大化的同时网络成本最低的sink节点个数的表达式。理论结果表明，该值与网络规模、关键节点数、节点收发功率以及普通节点和sink节点的成本等参数有关。最后通过仿真实验证明了该结论的正确性。

关键词: 无线传感器网络, 多sink节点, 网络寿命, 网络成本, 能量模型