Research And Implementation Of Applications Middle Layer In Wireless Sensor Networks

Wireless integrated sensor networks, which include collecting, processing data and communication, are used more and more widely for its low cost and convenient deployment. Nowadays the researches of technologies of sensor networks applications are fairly active. The middle layer, between wireless sensor networks and applications, can provide cross-operating system and corss-programming language data services to applications, which in the face of too much and complex development work and unable to focus more on the development of application logic because there are many different wireless sensor networks communication protocols and packet structures. At the same time, the data services provided by the middle layer can reduce coupling between applications and wireless sensor networks, therefore it can effectively reduce the workload of system maintenance when networks protocols changed. This article focuses on technologies and the realization of the middle layer of wireless sensor networks. The main works are as follows:(1) At first, this article introduced research of the middle layer of wireless sensor networks applications, and brought forward one kind of middle layer which is between wireless sensor networks and applications according to weakness of the traditional wireless sensor networks applications: designed the data interfaces which middle layer should have according as data flows of the traditional wireless sensor networks; through analysis of communication protocol and packet structures of the operating system for wireless sensor networks, extracted its packet structures'characteristics and got one kind of common data-processing method of middle layer.(2) Secondly, this article researched several technologies of middle layer: using generic serial port communication subassembly for the data interaction to heterogeneous wireless gateways and using TCP/IP, XML, Web Service, database and other technologies which are cross-operating system, cross-programming language to provide customizable data services to applications.(3) At last, based on hardware platform - the prototype system of data compression key technologies in the asynchronous wireless sensor networks environment, which is National 863 Plan committed by our laboratory, this article designed and implemented a middle layer software and a number of prototype applications based on middle layer, which included windows programs of C/S structure and web programs of B/S structure and which can be run on Windows and Linux platforms. Experimental results show that the middle layer which designed by this article can provide stable and reliable data services, with processing and forwarding ability for a large amount of data. At the same time, it can effectively reduced the coupling between applications and wireless sensor networks, therefore reduced its workload of development and maintenance.