Research And Implementation Of Remote Automatic Update System For Terminal Software Based On LoRa

As an emerging Low Power Wide Area Network(LPWAN)technology,LoRa technology has the advantages of long communication distance,low power consumption and easy deployment.It is widely used in the field of Internet of Things(IoT)such as smart meter reading,smart agriculture,smart industry and smart home.Along with the expansion of the application scale of LoRa IoT,the management,maintenance and upgrade of the terminal software are very important for improving the stability of the network.After the deployment of network,the terminal application software needs to be remotely updated and upgraded due to changes in application requirements.The software remote update technology can realize the remote upgrade of the terminal application software without contacting the terminal,which greatly improved the management and maintenance efficiency of IoT terminal device,and is of great significance to promote the intelligentization of the IoT.Firstly,this thesis introduces the research background and research status of LoRa technology and software remote update technology.It compares and analyzes the mainstream technology of LPWAN,and focus on the characteristics,network architecture and network protocol stack of LoRa technology.Meanwhile,it introduces the key update mechanism of software remote update technology in detail,including remote code update mode,online programming technology,data breakpoint retransmission technology,and analyzes the composition of machine code file.Then it analyzes the technical characteristics of existing software remote update solutions.Secondly,to deal with the problems of low efficiency of code data dissemination and high transmission control overhead during remote update code data dissemination,an efficient code data dissemination method based on network coding is proposed.The new method obtains solvable coding combination by using coding combination selection mechanism,and adaptively intercepts the effective coding information according to the minimum packet sequence number and the maximum packet sequence number in the coding combination to optimize the coding combination vector storage space,thereby reducing transmission coding information.It solves the redundancy control overhead caused by the "TRIG message" trigger mechanism using the last code block sequence number and the special coding packet sequence.The terminal nodes in the network are divided into multiple update domains by centering on the gateway.The gateway establishes a code data cache space and disseminates the cache code data independently within each update domain.Next,the LoRa-based terminal software remote automatic update system scheme is designed,including system architecture,hardware selection,remote update message frame format,server software solution,gateway software solution,terminal software solution and LoRa channel conflict avoidance mechanism.Then,this thesis implements the LoRa-based terminal software remote automatic update system scheme using VS2012 and IAR for STM8 development tools,and tests the basic functions of the system to verify the effectiveness of the system.Meanwhile,it tests and analyzes the system related performance.The test results show that the new mechanism reduces the code data dissemination control overhead and code data dissemination time overhead.Finally,this thesis gives a conclusion to the whole research work and points out the direction of further research on the remote update technology of terminal software in LoRa network.