Research And Design Of WSCN Nodes Remote Code Update System Based On MQX_Lite

WSCN node is a critical embedded component to accomplish terminal data collection, communication and target object control. As the rapid development of the Internet-of-Things, the online maintenance and function update of WSCN node’s programs are becoming a research hotspot of the application of Wireless Sensor Network. Nowadays, traditional update solution hasn’t been able to meet the requirement of a complex environment with numerous widely distributed nodes. Thus, the research and design of remote wireless code update has a high application value and practical significance.This paper designs a three-layer structure remote code update system based on Internetof-Things, it selects NXP semiconductor KW01 wireless RF chip and k64 chip as hardware object and divides mutiple task using the MQX_Lite RTOS. This paper’s research focuses on solving some of the key problems in remote code update like data transfer granularity, frame retransmission, transmission resuming and multiple point distribution. The main contents of these research work can be summarized as follows:(1) Scientifically analyzes the factor such as transmission speed, single frame data load, error rate and data integrity of which the data transmission granularity may has effect on.And proposes a selection method on account of data transmission granularity partition.(2) Designs a data frame bit table based on data frame status after researching the scene of data frame loss in data transfer progress. Proposes a reliable transmission code update mechanism base on mutiple handshakes and retransmission, which ensures the integrity of code update. Designs a transmission resuming mechanism based on file version and transport status to prevent the data loss due to broken network and cut-out. This mechanism also increases the speed of code update.(3) Designs a update status frame bit table which records the status of multiple nodes aimed at the application of multiple nodes’ mass updation. Proposes a mass distribution mechanism in which P2 P and several polling are applied.(4) According to the research work above, this paper designs a remote code update system of WSCN node, which includes analyzing chip’s storage image, dividing the flash image, designing link file, relocating interrupt vector table, designing boot program, designing WCUCP communication protocol for communication of gateway and nodes and designing RCUCP communication protocol for communication of server and gateway.(5) This system has been evaluated and tested by applying it in the control system of a LED display screen. Compared with artificial code update, remote code update system improves the efficiency of update significantly and reduces the update workload greatly.Contribution of this paper: Researches and solves the key issues of remote update. Designes a common and reliable remote update prototype system based on WSCN nodes, it may provide a reference to the development of similar system in the future.