Data Communication Mechanisms Of Service-Oriented Wireless Sensor Networks

Traditional wireless sensor networks (WSNs) are data-centric. The studies are mostly focusing on efficient routing protocols and data transmission mechanisms to reduce the energy consumption of messages. With the development of researches and the increasing diversity of application, current WSNs are aiming at services providing. In the service-oriented WSNs, researches shall take consideration of the whole network, the establishment and maintenance of the network structure, the transmission of raw data as services within the network, so as to reduce and balance node consumption and prolong network lifetime. Among the applications of large-scale WSNs, more innovative and cutting-edge research are devoted in how to build efficient network coordination mechanism, allowing the sensor nodes complete the application tasks in a regional autonomous and also collaborative way, to avoid overloaded root nodes and poor robustness in a centralized wireless sensor network.In this thesis, we first study a service-centric networking scheme, which is mainly applied in the underlying data communications of service-oriented WSNs. This scheme includes a networking algorithm based on routing distance, which organizes a huge number of nodes into a reasonable multi-level tree network, and hence make the inner data transmission more efficient. In this network, we also design a complete set of network management approach to manage network events and errors, so as to enhance the robustness and scalability of the network. Then, we study and extend the traditional publish/subscribe communication model, to further enhance the efficiency of data transmission of the proposed network. The study results show that this scheme achieves the goal of energy conservation and load balancing, and it shows a big advantage in expanding the lifetime and applicability of the network.In this thesis, we further study the distributed service rules processing engine, which is mainly applied in communication strategy on application layer of service-oriented WSNs. Aiming at overcoming the problems of current centralized control structures, we improve and realize a novel distributed control structure. And we use a comprehensive data synchronization approach, to achieve the regional autonomy. The prototype system shows that, the engine realized a large-scale distributed network architecture, reached the goal of load balancing and enhancing network robustness.