面向MC1321X的低开销无线重编程机制的研究与设计

STUDY AND DESIGN OF AN MC1321X-ORIENTED LOW-OVERHEAD WIRELESS REPROGRAMMING MECHANISM

无线重编程技术已经成为目前无线传感网研究的热点。然而,过高的代码更新量一直是无线重编程技术在实际大规模应用中的瓶颈。在分析与研究目前几种代码分发协议的基础上,提出一种基于MC1321X的低开销、高可靠、低延迟和低存储的无线重编程机制WSN_OTAR。该机制通过重新设计Bootloader对更新的代码进行重组以确保重编程的正确性;同时,解析MC1321X的机器码文件结构并设计差异化代码生成方法降低代码更新量的传输开销;在发送数据帧时采用轻量级的广播算法,有效地防止数据风暴;并采用丢失重传策略保证无线重编程的可靠性。最后,通过实验结果验证此机制在降低代码更新开销方面的有效性。

At present, wireless reprogramming technology has become a hot topic in wireless sensor networks （ WSNs） studies.However, too high codes updating quantity has always been the bottleneck of the wireless reprogramming technology in its large-scale practical application.Based on analysing and studying several existing code distribution protocols, we propose in this paper a wireless reprogramming mechanism called WSN_OTAR, which is based on MC1321X and has low-overhead, high reliability, low latency and low storage cost.In order to ensure the correctness of reprogramming, the mechanism regroups the updating codes by redesigning Bootloader.Meanwhile, it analyses the machine code file structure of MC1321X and designs the differentiated codes generation method to reduce the transmission overhead of codes updating quantity.When sending the data frames, it uses lightweight broadcast algorithm, this effectively prevents data floods.Moreover, the loss-retransmission strategy is also used to ensure the reliability of wireless reprogramming.At last, the effectiveness of the mechanism in reducing the overhead of codes updating is verified through experimental results.