Abstract: Considering the distributions of node’s energy consumptions in Wireless Sensor Networks（WSN），a modified hierarchical data aggregation protocol is proposed.Firstly，this paper sets up a simple model to analytically evaluate the energy consumption in WSN by using aggregation mechanism.This paper also shows that energy consumption of an aggregation node increases so rapidly in the neighborhood of the sink node that these nodes will die and shorten the lifetime of the whole network.Secondly，a modified hierarchical data aggregation strategy in order to achieve balanced energy depletion by reduce the cluster head selection probability near the sink is proposed.Simulation results show that，this method can reduce the energy consumption efficiently for sensor networks.So，it can prolong the lifetime of the whole networks.

Key words: Wireless Sensor Network（WSN）, aggregation, energy-efficient, hierarchy

摘要： 考虑WSN中节点的能耗分布情况，提出了一种改进的多级汇聚协议。首先建立分析模型评估了在WSN中采用多级汇聚机制时的能耗情况，证明在SINK附近的汇聚节点的能量增加很快，从而会耗尽能量，缩短整个网络的生存期。然后提出了一个改进的多级汇聚协议，通过改变通过减少离SINK附近的汇聚节点选择概率，可以均衡网络性能。仿真结果证明，该方法可以有效地降低能量，从而延长网络生存期。

关键词: 无线传感网, 汇聚, 能量有效, 分级