DPWS Middleware For Wireless Sensor Network

Wireless sensor network is the self-organized network, which is formed by a plenty of the tiny sensor nodes with the capacity of perception, communication and computing. Given its low costs , rapid deployment capabilities and flexible, it is widely used in the prospects of military, security, environment, industry, transport, health care and housing, etc. At the same time, the diversity of applications and the heterogeneity of hardware platforms bring challenges to the applications during the development, deployment and maintenance. DPWS (Device Profile for Web services) is a subset of Web services. DPWS can view equipment as a service, wrap the function of sensor nodes and network as services with uniform format, hide the heterogeneity of underlying hardware platform, network protocol and operating system, simplify the development and deployment of the application. However, network bandwidth, memory capacity, processor computing power, power and other resources are very limited in the wireless sensor networks, the common DPWS implementation can not be supported here. To solve this problem, MinyDPWS achieved theDPWS specification in resource-constrained wireless sensor networks.In order to save resources, MinyDPWS use the dictionary based algorithm to compress the messages of SOAP(Simple Object Access Protocal).The both sides of the communication communicate with each other based on the dictionary, so that the energy required to send the message and network bandwidth consumption can be efficiency. MinyDPWS use the model-based compression algorithm to compress the files to reduce the storage of the files , according to the characteristics of WSDL (Web Services Discription Language) files. In addition, the middleware also supports the service discovery mode, which is suitable for the environment of wireless sensor network and application requirements. The service discovery mode work in the service agent mode by default, it can support the dynamic mode switching between the Ad hoc mode and the service agent mode according to application needs. System tests show that, MinyDPWS middleware to achieve the intended results. As compared with other middleware, it can reduce the time for service calls, reduce communication costs, effectively compress the WSDL files, is able to switch dynamically according to application needs service discovery mode, rapidly discover service, reduce communication costs during the service discovery.