The Design And Realization Of Publish/Subscribe Middleware For Wireless Sensor Networks

Wireless sensor networks (WSNs) have been applied in a wide range of area. The resource-constrained runtime environment, dynamic topology and heterogeneity of underlying hardware lead to difficulties in developing WSNs application. The problem can be resolved by introducing the middleware into WSNs.In this paper, the application targets and functions of WSNs are summarized. By considering characteristics of WSNs, the challenges of middleware for WSNs are analyzed. According to different programming paradigms, the middleware for WSNs are classified and evaluated, it proposes the designing principles of middleware.Based on principles above, a publish/subscribe middleware for WSNs is put forward. The middleware employs a three-tier architecture, cluster member, cluster-head and sink. They use publish-and-subscribe messaging to communicate among them. In order to decrease energy consumption of nodes, multiple levels data fusion is processed during the transmission. Different types of applications can access data in a uniform way through a RESTFul query interface, which is provided by the middleware.Based on Contiki, an embed operation system, a prototype system of middleware is realized. Finally, the prototype is verified and evaluated by a simulation case study. The simulation results show the functions of middleware have achieved the target of design. Energy efficiency and response rate of the network using middleware, compared with the network without using middleware, is improved remarkably.The thesis is supported by the National Natural Science Foundation Project(No:612610001), named "Research on key technology of data aggregation and transmission in WSNs and its application in facility agriculture in semiarid areas".