| As the hot point of future technology,the Internet of things has developed rapidly in recent years.On the theoretical side,the Internet of things protocols and standards emerge,and companies are actively deploying in the Internet of things.In terms of applications,many vertical industries have a mature Internet of things solution.However,local connectivity is not the ultimate goal of the Internet of Things.In order to achieve cross-platform,cross-device high-level interconnection,it is imperative to solve the problem of conversion between protocols.Based on oneM2M protocol,the research of heterogeneous network integration is carried out.The main work is as follows:(1)A protocol conversion scheme for oneM2M and OCF,as well as oneM2M and ZigBee was proposed.The protocol transformation includes three levels:resource model layer,message message layer,and functional service layer.In this paper,the protocol transformation of resource model layer proposes a conversion method of OCF device and ZigBee device to oneM2M resource tree.The protocol transformation of the message layer provides a mapping method between two protocol fields.The protocol transformation of the functional service layer puts forward the process of using oneM2M general service function for OCF devices and ZigBee device.(2)Aiming at the characteristics of massive data and high concurrency in the Internet of Things environment,this paper proposes a subscription mechanism based on rule matching and a notification mechanism based on multi-level forwarding.The former mechanism determines the data transmission mode according to the preset rules,which greatly saves the storage space of oneM2M nodes and reduces the communication burden.The latter uses greedy algorithm to divide the notifications,which can reduce the average notification time of the system.(3)Built and development the prototype system based on OM2M open-source platform,realize OCF and oneM2M,Zigbee and oneM2M protocol conversion plug-in based on the proxy mode,and verify the following three processes in the oneM2M system:OCF device discovery and registration,OCF device data reporting,OCF device control.Finally,the efficiency of the system is tested by simulating the data flow in the real environment.When the Internet of things protocol is not unified,protocol conversion is the best solution to realize cross platform interconnection.At the same time,the protocol conversion plug-in based on proxy mode has good scalability,which provides ideas for other IOT protocols to access the oneM2M system. |
