Research And Implementation Of Interoperability Between Devices In BLE Constrained Network And The Internet

In recent years,with the rapid development of the Internet and wireless communication technologies,coupled with the popularity of smart terminals,various and large numbers of devices have been connected to each other to form the Internet of Things.Devices in resource-constrained networks are characterized by low power consumption,low processing capacity,and small storage space.Limited by these conditions,enabling resource-constrained devices to support interaction with Internet devices at different network levels has attracted attentions in academia and industry.Bluetooth Low Energy(BLE)constrained networks have their own network characteristics.The devices in them being directly accessed and operated by the Internet devices requires cooperation between resource-constrained devices and gateways.The protocol stack support for resource-constrained devices with further refinement and the situation that smart devices act as gateways to provide interoperable interfaces to resource-constrained devices over the Internet remains a key issue that must be addressed.Therefore,in this paper,according to the scenes of BLE communication for two typical devices as gateways,combined with the REST-based Constrained Application Protocol(CoAP)proposed by the The Internet Engineering Task Force(IETF)CoRE working group,the interaction between BLE constrained network devices and Internet devices is studied.It is considered from two levels:technical interoperability to guarantee basic communication capabilities and semantic interoperability to guarantee basic information processing capabilities.The research contents and work of this paper are as follows:Firstly,the research and implementation of the technical interoperability mechanism of BLE constrained devices and Internet device.Supporting the CoAP protocol is a pre-foundation of further support for semantics.In the case of mobile smart devices as gateways,with the restriction that IPv6/BLE cannot be supported in Android system ar-chitecture,a non-IPv6 CoAP message transmission mechanism on the native BLE complete protocol stack is proposed to solve the corresponding limitation problem,and this is used as one mode to support CoAP transmission.Supporting CoAP/UDP/IPv6 on the BLE link layer is another mode.This paper designs and implements the 6LoWPAN for BLE adaptation layer and proposes an adaptive control mechanism.Experimental results show that this will optimize IPv6 communication based on BLE.The research on the related mechanism of the latter mode lays the foundation for supporting the CoAP/UDP/IPv6 mode after the restrictions are released on the subsequent versions of Android.Secondly,the research and testing of the semantic interoperability mechanisms between devices.Based on the technical interoperability mechanism in the BLE constrained network provided by the first research content,and combined with ontology modeling technology,a decision-making model of semantic association is constructed for the semantic description information of sensors.With the problem that no semantic analysis has been done in the field of specific scenarios in other related studies,an extended scenario-related semantic model is proposed.Then the semantic interoperability in one specific domain is reflected.In the fire-fighting related scene of the high-speed carriage,the fire safety status and the fire hazard occurrence status are evaluated according to the multi-factor ontology modeling and comprehensive evaluation rules,and the alarm decision is made according to different status levels.