基于Contiki的WSN节点重编程技术研究与设计

发布时间：2018-07-18 10:10

【摘要】：无线传感网络概念自被提出以来,在MAC、路由层协议、功耗、组网等方面获得长足的研究与发展,并在工业现场监控、无线抄表、智能建筑、智能家居等场景下有广泛应用。与实验阶段的节点不同的是,安装在实际应用场景下的节点会因为客观环境影响以及人造因素等产生与设计需求相偏离的变化,并且在一些环境下硬件更换的难度较大、成本较高,节点的软件生命周期受限于外界因素而缩短,研究对已部署的节点进行功能更新的重编程方法成为迫切而重要的课题。随着嵌入式软件设计方法的不断进步,针对无线传感网络的操作系统也越来越多受到关注与重视。首先,本文对无线传感网络的各操作系统进行了详细的比较与分析,并对现有的重编程方式以及无线代码分发协议进行了介绍与对比。本文选取事件驱动型的微内核操作系统Contiki作为研究对象,重点深入研究了其采用的Protothread线程原型,对该线程的优缺点进行了总结分析。另外简要介绍Contiki提供的一个完整的软件平台包括可以运用在无线网络的Rime通信协议栈,基于Flash存储器的微日志文件系统Coffee,以及能够运行在8位微控制器上的微型TCP/IP协议栈uIP。其次,本文主要设计了重编程的两种方案,一种是整体重编程,另一种动态加载的重编程。整体重编程是传统的IAP,该方式是将嵌入式生产力工具生成的二进制可执行文件完整覆盖替代旧存储区的装载域文件,并重新引导系统启动而完成升级。第二种动态加载模式采用了Contiki集成的ELF loader工具进行可重入目标模块的解析、加载和运行。在K64F硬件平台上分别针对两种重编程方式,进行了软件框架设计和试验,并针对这两种升级方式,在升级粒度和深度两个维度上进行了比较。同时,本文针对重编程过程中文件的传输安全以及数据完整性进行了可靠性设计实现,提高映像文件升级的容错性。最后,对本文的研究进行了总结,提出在实施设计过程中出现的一些问题及不足。在可移植性方面,动态加载方式还不能移植到采用非ELF可重定位文件的微处理器,这为下一个研究阶段的的任务明确了方向。
[Abstract]:Since the concept of wireless sensor network (WSN) was proposed, it has gained considerable research and development in Mac, routing layer protocol, power consumption, networking and so on, and has been widely used in industrial field monitoring, wireless meter reading, intelligent building, smart home and so on. Different from the nodes in the experimental stage, the nodes installed in the practical application scenarios will deviate from the design requirements because of the objective environment and artificial factors, and the hardware replacement is more difficult in some environments. Because the cost is high and the software life cycle of nodes is limited by external factors, it becomes an urgent and important issue to study the reprogramming method for updating the functions of deployed nodes. With the development of embedded software design, more and more attention has been paid to the operating system of wireless sensor network. Firstly, the operating systems of wireless sensor networks are compared and analyzed in detail, and the existing reprogramming methods and wireless code distribution protocols are introduced and compared. In this paper, the event-driven microkernel operating system Contiki is selected as the research object, and the Protothread thread prototype is deeply studied, and the advantages and disadvantages of the thread are summarized and analyzed. In addition, a complete software platform provided by Contiki is briefly introduced, including Rime protocol stack which can be used in wireless network, micro log file system Coffeebased on Flash memory, and micro TCP / IP protocol stack uIPs which can run on 8-bit microcontroller. Secondly, this paper mainly designs two schemes of reprogramming, one is whole reprogramming and the other is dynamic loading reprogramming. Whole reprogramming is the traditional IAPs, which completely overwrites the load domain file instead of the old storage area by the binary executable generated by the embedded productivity tool, and reboots the system to complete the upgrade. The second dynamic loading mode uses the Contiki integrated ELF loader tool to parse, load and run the reentrant target module. Based on the K64F hardware platform, the software framework is designed and tested for two reprogramming methods, and the upgrade granularity and depth are compared. At the same time, this paper designs and implements the reliability of file transmission security and data integrity in the process of reprogramming to improve the fault tolerance of image file upgrade. Finally, the research of this paper is summarized, and some problems and shortcomings in the implementation of the design are put forward. In terms of portability, dynamic loading can not be transplanted to microprocessors with non-ELF relocatable files, which makes clear the direction of the next research stage.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP212.9;TN929.5

【相似文献】