【作者】 霍宏伟；

【导师】 张宏科； Youzhi Xu；

【作者基本信息】 北京交通大学 ， 通信与信息系统， 2010， 博士

【摘要】 摘要：随着医用传感器技术的进步,实现基于无线感知和监测功能的远程医疗护理系统为无线传感器网络设计实现杀手级应用提供了重要契机。但是现有的无线传感器网络系统无法很好的支持医疗监测和医疗护理的核心需求,在网络架构、组网技术和服务提供等诸多方面都存在问题,亟需解决。本文根据医疗护理特别是医疗监测应用的特点,论述了医疗护理无线传感器网络的设计难点,提出了模块化的医疗护理传感器网络结构描述；对系统的无线信号特征、链路层协议、网络层协议、会话层支撑协议等关键通信技术问题进行了深入研究,并探讨了如何将其具体应用于老年人生活与身体状态的全天候监测之中。1.分析了医疗护理无线传感器网络工作环境的特殊性。基于实验总结了医疗护理无线传感器网络无线信号的室内外传播特征、估计了人体对信号传输的影响;通过实验分析了室内条件下多种2.4GHz设备的共存问题,提出了一种多信道单射频条件下的干扰避免机制。实验结果表明,该机制可以有效克服因同频干扰造成的节点间数据报文的丢失的问题。2.讨论了医疗护理无线传感器网络对MAC协议的需求。针对IEEE 802.15.4用于体域传感器网络(Body Sensor Networks)存在的Beacon冲突和簇GTS串音问题,提出了一种改进的MAC协议：BS-MAC:通过添加命令帧的方式减小了Beacon冲突,通过协商机制解决了簇GTS串音问题。仿真结果表明BS-MAC相比其它常用体域网MAC协议在吞吐率,时延,能耗等性能指标方面有一定程度的提升。3.分析了医疗护理场景对无线传感器网络路由协议的需求。在体域传感器网络与固定传感器网络混合场景下,改进了传统地MintRoute路由,利用加速度传感器测得的人体运动信息,设计了一种基于内容的简单汇聚路由,减小了通信开销。在多数节点固定的场景下,利用不完全超立方体的概念实现了基于链路层的路由机制,使网络很好地支持了本地数据存储和查询。在被监测对象在公共区域移动的场景下,提出了一种基于移动体域网节点组的最小方差均衡数据收集方法,可以有效平衡节点间数据转发的能耗。仿真和实验结果表明,上述三种机制能够满足各自场景下的路由需求。4.提出了一种多域传感器网络节点之间的端到端互联方法,尝试将SIP消息的通信过程与拓扑生成过程相耦合；针对C4SD分簇拓扑生成算法不能动态反映簇首能量消耗的问题改进了该算法,提出了一种在分簇拓扑下的SIP耦合方法：H-SIP。仿真结果表明,H-SIP可以在动态传感器网络中高效地实现SIP绑定和用户发现。5.设计并实现了老年人健康监测系统,该系统可以动态监测老年的日常生活状态,并对他们的日常活动进行统计,对危险状况的发生进行告警；并能够将监测到的状态利用移动电话、E-mail、SMS等方式通告给被监测对象、亲属、医生或护士等相关人员。在此基础上,提出了一种老年人的行为、位置估测方法,可以检测老年人跌倒等特殊行为；实验结果证明该方法具有较高的检测准确性。更多还原

【Abstract】 ABSTRACT:With the rapid development of medical sensor technology, the wireless sensor networks(WSN)based technology has invaded the Medicine and Health Care scopes.At the same time, me new requirements of Health Care applications, Such as achieving universaL, seamless wireless sensing and other long-distance medical care, proyide an important opportunity for finding killer application of wireless sensor network.However, current WSN systems can not support the core requirements of medical monitoring and health care very well.Many aspects of the existing problems urgently call for solutions.In this dissertation, the characteristics of the medical monitoring application are analyzed, the system architecture is re-designed, and several key communication protocols in link layer, network layer and session layer are proposed.A WSN based health care system for senior citizens is also designed and implemented to explore the dailylife of senior citizens.1.The mutual interference effects of 2.4 GHz devices widely deployed at home are examined via both theoretical analysis and real-life experiments.An analytical model is proposed to estimate me packet error rate(PER)of radio frequency(RF)coexistent networks.The model is verified through a series of experiments.An interference avoidance model is also proposed, which is based on multi-channel and single radio selection scheme.Experimental results show this scheme can reach high performance.2.When IEEE 802.15.4 is deployed in body area networks,there will be several key issues, including Beacon Conflict, and Inter-cluster GTS Crosstalk.In this dissertation, an improved MAC protocol, named BS-MAC, is proposed to solve these issues.By adding the command frame in IEEE 802.15.4, BS—MAC reduces the effects of Beacon Conflict, and Inter-cluster GTS Crosstalk.To verify and compare the performance of the BS—MAC, T-MAC,the traditional IEEE 802.15.4 and other protocols, a series of simulation experiment are executed.SimulatiOn results show that BS-MAC Can achieve a certain degree of upgrading in throughput, delay and energy consumption compared with other MAC protocols mentioned above.3.The communication requirements in difierent application scenarios of wireless sensor networks based health care systems are very complex. Several new communication schemes are required to dynamically fulfill these requirements and achieve efficient data transmission.3 novel routing schemes are introduced individually including modified MintRoute (designed for simple data collection scenario), Virtual Hypercube Routing (designed for stationary scenario) and MinVar Data-collection Scheme (designed for group BSN sinks mobility scenario). Simulation results show that these 3 schemes can achieve high routing performance individually.4. A new approach, named H-SIP is proposed to couple SIP with wireless sensor network based health care system by jointing the session initiation process with WSN topology generation process. In this approach, more consideration is given to improve the dynamic-message-update and energy-saving-mechanism of SIP communications. Simulation results show that H-SIP can be used in the dynamic sensor networks, which is suitable for medical care applications.5. A prototype of WSN based health care system for senior citizens is deployed by integrating wireless sensor networks and the technologies of public communication networks to construct a healthcare system for senior citizens at home without interfering their daily activities. Based on this prototype, a novel location and activity detection approach is proposed to detect accidental falls for senior citizens. A series of experimental results show that this system can perform high validity and reliability.更多还原