Research On Routing Protocols And Localization Algorithms For Wireless Sensor Networks Orienting Telemedicine Monitoring

Along with the advances of Micro Electro-Mechanical System (MEMS) technologies, embedded computing technologies, communication and sensing technologies in recent years, wireless sensor network (WSN) has developed into a technology with advantages including low wiring costs, good fault-tolerant ability, high monitoring precision, convenience for remote supervisory and controlling, easiness of system diagnosis and maintenance and can be applied to many fields such as military affairs, medical treatment, project inspection, environmental protection and so on. As a resource constrained system, WSN faces many restrictions in aspects such as calculating, storing and network bandwidth. So it is significant to investigate the system architecture, routing protocols and localization Algorithms of WSN.The system architecture and related theories of WSN were studied and discussed in detail. The characteristic analysis of network layer routing algorithms were emphasized, and several popular routing algorithms applied to WSN were classified, compared and analyzed. Based on these research and analysis, the main contributions of this dissertation are as follows.(1) A fixed-partition routing algorithm based on energy balance is proposed in this thesis aimed at large-span space, complex environmental structures, requirement for long-term running of telemedicine monitoring system.Via adopting optimized cluster radii and multi-hop routing algorithm, energy consumption for intra-cluster communication is effectively reduced without the problem of energy hole. By employing the idea of fixed partition, stable distribution and constant amount of cluster-heads are achieved. In addition, the self-examination mechanism of cluster-head energy is proposed to avoid overmuch control message. Furthermore, in the cluster-heads election phase, the nodes’ residual energy and geographic locations are fully taken into account. Simulation results demonstrate that this algorithm has outstanding performance in terms of network energy consumption, balance of node load, and network lifetime.(2) Considering the importance of efficient and accurate localization of telemedicine monitoring system, a novel localization algorithm CBMDS (Cluster-based Multi-dimensional Scaling) based on the conceptions of clustering hierarchy and MDS(Multi-dimensional Scaling) is proposed. Without the restrictions of anchor nodes’number and network connectivity, which are the deficiencies of other MDS-based algorithms, efficient and accurate localization is achieved by this algorithm via employing relative information obtained during routing process. Simulation results demonstrate that this algorithm has outstanding performance in terms of accuracy, real-time and system independence.(3) Based on the analysis of structure and composition of telemedicine monitoring system and the comparison on the existing technologies, a novel telemedicine monitoring system based on wireless sensor networks,was proposed and the hardware and software design realization based on ZigBee technology was given. The system has a clear designing structure and very kind expansibility,which can effectually strengthen the monitoring capability and widen the monitoring scope.