Design And Implementation Of LoRa-based Internet Of Things Communication System

With the rapid development of Internet of things technology,Lo Ra stands out from many LPWAN technologies by virtue of its unique technical advantages.Although the Lo Ra network based on SX1301 chip has strong network capacity and communication ability,the chip is not open-source,expensive and high development cost,which is not conducive to the development of low-cost,small-scale Lo Ra ad hoc network.Lo Ra WAN protocol based on ALOHA mechanism has some defects in the conflict rate of communication,which makes Lo Ra WAN unable to meet the requirements of some application scenarios.Therefore,this thesis designs and implements Lo Ra Mac ad hoc network protocol based on TDMA,and designs and develops Lo Ra terminal and Lo Ra gateway with SX1278.In order to save and display Lo Ra data,this thesis introduces web technology into the Internet of things,and designs and develops the Internet of things data cloud platform.The main work of this thesis is as follows:(1)This thesis analyzes the communication characteristics of Lo Ra,compares the advantages and disadvantages of many kinds of MAC,designs and implements a MAC layer protocol of Lo Ra Internet of things based on TDMA,to ensure that Lo Ra terminals automatically network and periodically upload data.(2)Using SX1278 communication module,Lo Ra terminal and Lo Ra gateway are designed and implemented.Lo Ra terminal adopts periodic listening and sleeping mode to ensure low power consumption.Lo Ra gateway transplants u C/OS-II operating system and Lw IP network protocol stack,which is easy for function expansion.(3)Based on Node.js and Express service framework,the data cloud platform of the Internet of things is designed and implemented,which is suitable for the IO intensive and high concurrent application scenarios of the Internet of things.The server implements user management and data management functions,and provides rest API interface.The token authentication mechanism is designed to improve the security of the platform.In the front-end,the SPA is designed by using Amap JS API,which provides users with map application and data access functions.The experimental results show that the designed Lo Ra MAC protocol can realize the conflict free uplink communication of Lora terminal,the data cloud platform can manage and access Lo Ra data,and realize the single channel Lo Ra Internet of things communication system.The system provides a solution for building a small-scale and low-cost Lo Ra network,and has a good application prospect.