Research And Application Of File Transmission Method For Internet Of Things Based On MQTT

Since the concept of the IoT was put forward,it has attracted extensive attention from all over the world,and has become a technology developed by all the major powers and organizations in the world.With the continuous deepening of IoT technologies and applications,information sharing between objects in IoT is no longer simply message delivery,achieving end-to-end file transfer is needed by more and more IoT application systems.Studying the end-to-end file transfer method in IoT is of great significance for promoting the development of the IoT technology.By analyzing the characteristics of data transmission in IoT,aiming at the limited resources of the equipment,the unstable network environment and the dynamic change of the network structure,the file transmission method in IoT is studied on the basis of MQTT communication.The main work is summarized as follows.(1)Aiming at the end-to-end file transfer needs in Io T system,a method of end-to-end file transfer using MQTT protocol for files splitting,numbering,segmented transmission,parsing,sorting and combination is put forward,the acknowledgement reply and timeout retransmission mechanism are adopted to ensure the reliability of file transfer.The binary data encoding method is studied and the file data is coded to solve the problem that the file data can not be transmitted by the byte array when the file data is transmitted in JSON format.(2)A method of end-to-end file transfer is proposed based on MQTT protocol and TFTP.TFTP protocol is used to achieve file transfer between end to cloud,and through the sliding window to control the sending and receiving of file data to improve the efficiency of TFTP file transfer.Combined with the MQTT protocol,the message notification between end-to-end is realized based on the topic-publishing and subscribing,thereby realizing the end-to-end file transfer of IoT system,which solves the problem of low efficiency in transferring large files using the MQTT file transmission method.(3)Two kinds of file transmission methods studied in this thesis are applied to the landscape lighting control system,and the hardware and software design of the system gateway is completed,and a complete test system is built to carry out practical application and test.The implementation process and method of gateway?s MQTT communication,controller parameter configuration,log file transfer,pattern remote update and so on are described in detail.The application and test result show that the end-to-end file transmission method using MQTT protocol,the end-to-end file transfer combined with MQTT protocol and TFTP protocol,are stable and reliable,and have achieved the end-to-end file transmission in the IoT system,and has practical application value.