Design And Implementation Of Unified Connection Framework Between Sensor Network And Cloud

With the rapid development and convergence of cloud computing technology and Io T applications,sensor cloud has become an emerging cloud computing platform,supporting interconnected sensor devices to interact with cloud applications and other devices.Intelligent data analysis of the Internet of Things in the cloud center has become an important component in the fields of smart city,intelligent manufacturing,and smart home.However,there are still some key issues that need to be solved in the process of building a sensor cloud,such as unified access to heterogeneous sensor networks,real-time data processing,and hot update of gateway applications.In this paper,we design a unified connection framework between sensor and cloud,combined with OSGi,Spring,My SQL,Java EE and other technologies,implement the plugin hot-loading gateway and server-side control platform in detail,including dynamic loading module,heterogeneous sensor network adapter,data channel mdoule,device authentication module,notification module and other necessary modules.Finally,all modules integrated together constitute a sensor and cloud unified connection framework.Aiming at the unified access problem of heterogeneous sensor networks,we propose a sensor network adapter solution that can integrate network communication protocols such as Wi Fi,Zig Bee,Wireless HART and serial port.The solution distributes data packets of different sensor networks to corresponding protocol parsers through independent sensor network communication adapters,and the protocol parser performs data parsing and generates data objects according to a unified data format.In view of the problem of application interruption caused by application upgrades in sensor applications,we study the class loading mechanism and select OSGi technology for dynamic loading gateway implementation.The proxy pattern is used to improve the OSGi bundle update process,the new bundle is loaded in advance,and the old bundle is dynamically proxyed.After the proxy process is completed,the new bundle implements the hot replacement of the old bundle.The gateway implemented by OSGi technology can deploy various applications,which can realize the functions of analyzing,processing,and filtering the raw data of the sensor network with the advantages of saving network bandwidth and supporting real-time data processing.In order to realize the transmission and control of the cloud service center to the gateway,we design the MQTT-based transmission control protocol and the high-speed data transmission channel based on Netty,both of which support digital certificate-based TLS two-way identity authentication and transmission encryption.The MQTT protocol ensures reliable transmission of control commands in low-quality network environments,while the Netty multi-threaded transmission channel assures high-speed data communication.Finally,we build a heterogeneous sensor network environment to test key functions in the framework.The test results show that:(1)sensor data of different protocols can be uniformly connected and delivered to the cloud center;(2)the cloud center can remotely perform hot update and configuration management to the gateway;(3)the gateway example application can collect and filter sensor data correctly,and can prevent data loss caused by temporary network interruption.