The Design And Implementation Of Lightweight Publish/Subscribe System Based On IOT

The rapid development of the Internet of Things and mobile Internet technology provides an unprecedented opportunity for the growth of enterprises. At the same time, more and more enterprises and organizations have started to focus on information technology in order to improve their own competitiveness. To have more efficient access to data and use it, you need the help of data distribution technology. Publish/Subscribe system is a middleware system to make the parties in distributed system participate in the interactive messaging activities as a publisher or subscriber, which was applied widely in distributed systems.The lightweight Publish/Subscribe system was proposed under analysis of current research and the demand of IoT environments. The system is based on MQTT protocol, and has completed the design and implementation of server and client, and the communication process between server and client. To adapt to the instability and low bandwidth of wireless sensor networks, this paper has designed a new theme codec algorithms for MQTT message to improve the efficiency of message transmission. In order to distinguish between the alarm information and environment data and meet the personalized needs of users, this paper has expanded the emergency attribute of message and proposed priority routing algorithm for emergency information. In order to reduce the routing pressure, this paper extended the semantic of message on the basis of the topic filtering, and has reduced the redundancy of the message and improved the efficiency of the system based on the message checksum mechanism. In addition, this paper has provided external RESTful interface, so subscribers can access data anytime, anywhere via a browser.Finally, this paper tested the performance of the system. The results show that this system is more lightweight, higher throughput per unit time compared with traditional Publish/Subscribe system. So this system is more suitable in the environments of the Internet of Things.