传感网络中基于消息预取的移动查询

Mobile querying technology based on message prefetch in wireless sensor network

针对无线传感器网络向终端用户传送信息的数据服务问题,提出了一种移动环境下满足时间空间约束的数据查询处理技术。结构上由代理体和网络节点两层组成,其中网络节点执行消息预取、查询分散和数据收集处理功能,通过对用户的运动路线进行预测并向传感节点发出预取消息,由节点自主构建网络查询树,再由数据集中组件完成数据的收集和融合,用户在到达传感区域后能在查询周期结束前获取查询数据。对该技术的性能进行了理论分析和实验仿真,结果表明在能耗增加不多下,移动查询能保持良好的数据完整性和高的查询成功率,验证了该技术的有效性。

To study the data service technology in terms of the information transmission to the mobile user through a wireless sensor network, a data query processing scheme called ＂Mobile-Query＂, which meets the spatiotem- poral constraints, is developed as well as its system architecture and query model. The system is composed of a proxy and network nodes. To improve the quality of the data service, the just in time （JIT） mechanism is adopted to transmit prefetching message utilized for initializing the query tree and re-scheduling nodes＇ sleep periods before the user＇s reaching the query area. Therefore, query results can be sent back to users just before the deadline of query period. Both theoretical analysis and NS-2 based simulations are carried out to investigate the performance of this scheme. The results show that the proposed scheme combines the advantages of the good data integrity, the high percentage of successful queries and the obvious improvement in the quality of data service while only comsuming a little additional energy of the network compared with IEEE 802.11 Power Saving Mode （PSM）.