Researches On SOA-based Middleware In Internet Of Things

Internet of Things (IoT), a novel communication technology, has graduallyaroused great academic attention recently. Its main idea is to bridge up betweenphysical world and digital world which requires key technologies from several fieldssuch as barcode, radio frequency identification (RFID), near field communication(NFC) as well as wireless sensor network (WSN) et al. These technologies build upphysical layer which generate massive information in a heterogeneous way. Thereforethe study of IoT middleware technology is crucial enough to provide a unifiedprogramming model to screen detailed interaction among heterogeneous resources.As a nexus of different technologies in the field of communication network,middleware technology plays a key role in IoT. In this study, a deep and thoroughanalysis about the existing problems among researches of middleware technology isgiven, which lead to the conclusion about key research in middleware and its trend ofdevelopment. Based on the environment of implementation, a universal architectureof middleware is proposed which better realizes interconnection andintercommunication between sensor layer and application layer. The separation ofapplication software middle layer and embedded software middle layer offers apromising solution for embedded intelligent devices with heterogeneity to beaccessible in IoT.Service-oriented architecture (SOA), as a software design method, providesservices for terminal users or other internet services through published and discoveredinterfaces. Considering about the unique features of IOT and superiority of SOAdesign, a SOA-based IoT middleware model is proposed. By packing differentfunction units into services for middleware platform and with the help of ESB that setup the connection between users’ request form upper layer and responded servicesform lower layer, the problem caused by frequently calling among IoT applications aswell as their interoperationality can be solved，which can not only improve the utilityrate of different resources but also lower down the design cost of applications.Additionally, a design model of service-based middleware prototype system is offeredto demonstrate applicability and effectiveness of the proposed architectures.To solve the problems created by insufficient consideration of existing algorithmabout requesters’ preference and load balancing of both service provider and requester, a service discovery and matching algorithm is presented based on QoS and requestpriority. With the application of the algorithm, request level can be determined basedon users’ QoS requirements. Also, users’ requests and responded services can bematched according to the designed utility function as well as the correspondingmatching strategy. Finally, simulation experiments are taken to evaluate theperformance of the algorithm in terms of responding rate, load and average QoSattribute.