Optimization,Implementation And Validation Of The MQTT Protocol For The Railway IoT Platform

In recent years,the Internet of Things industry has developed rapidly,and it has been widely used in smart home,smart medical,smart railway and other fields,providing great convenience for people’s lives.With the increasing number of devices connected to the Internet of Things in railway scenarios,in order to promote the construction of large-scale railway Internet of Things connections and related application systems,the railway Internet of Things platform came into being.If the railway Io T platform is a bridge that seamlessly integrates business application systems and on-site hardware devices,and is in a "hub position" of the combination of software and hardware,then the MQTT protocol is the channel from the equipment to the railway Io T platform.The MQTT protocol is a lightweight application layer protocol based on subscription/publishing.It is designed to provide reliable messaging services for resource-constrained devices in low-bandwidth and unreliable network terminals.Its lightweight,simple,and reliable characteristics are very suitable for The Internet of Things environment has a wide range of applications in the Internet of Things.However,with the development of the Internet of Things,in the face of some new scenarios,the MQTT v3.1.1 protocol has some shortcomings,so the MQTT v5.0 version was launched.After investigation,it is found that most of the devices connected to the railway Io T platform use the MQTT v3.1.1 protocol,and the new version of MQTT v5.0 has not been used.Therefore,this paper studies the MQTT v5.0 protocol and explores its performance compared with MQTT v3.1.1.To improve and face the remaining deficiencies of the new scene,the specific content and contributions are as follows:(1)The new features of the MQTT v5.0 protocol are summarized and sorted out.In recent years,in order to adapt to the development of the Internet of Things,MQTT v5.0was born.However,at present,most devices connected to the Internet of Things platform and engineering research still use MQTT v3.1.1.Therefore,this paper explores the functions of the new version based on the current needs of the Internet of Things.Advantages and necessity of research for MQTT v5.0.(2)Analyze and improve the shortcomings of the MQTT v5.0 protocol.Although the MQTT v5.0 protocol has been upgraded and improved,after research,it is found that there are still situations that do not meet the needs of some scenarios,such as the inability to dynamically modify client subscriptions,the inflexibility of shared subscriptions,and the long subject names of subscription messages.Research is conducted to optimize protocol design for these problems to meet the growing demand.(3)Implement and verify the design improvement scheme.Based on the above analysis of requirements and design of functions,in order to make the server have better portability to various operating systems,the Java language is used to implement.Then carry out functional and non-functional tests on the realized system,and analyze the test results.The results show that the system implemented in this paper conforms to the design logic and meets the requirements of the scene.The research results of this paper will provide reference value for the improvement of MQTT protocol.