Research And Implementation Of Query Mechanism In Wireless Sensor Network

Wireless sensor network is a new research area, and any application can not be implemented without processing and analyzing sensor data. So the technology of managing and processing sensor data is very important. The major contribution of this thesis is stated as follows:⑴According to the characteristics of WSN, this paper designs and implements a query language NHSenSQL for sensor network. NHSenSQL is a language like SQL, it supports selection, join, projection and aggregation, and also supports the data acquiring and sampling. In this paper, NHSenSQL considers the spatial characteristic of WSN, and it can support spatial queries.⑵The paper analyzes the query processing of NHSenSQL, including the parse technology in PC and the processing technology in network. The client parses the NHSenSQL, makes the query implement plan, and sends the plan to the network. The network distributes the query messages, collects the data and sends the result back.⑶At present, most researches are focused on single-spatial query, and very little on multi-spatial query. The paper proposes three methods, the method based on flooding, the method based on GPSR and the method based on multicast routing. And it compares the energy consumption of these methods according to the simulation experiment.⑷The probability of the data occurs and the sample costs of different sensor are always different. According these two factors and the influence within each properties, the paper proposes a optimize method. In addition, there are always more than one query sending to the network, the paper proposes the model of virtual query that is the only one query in the network, and it gives the arithmetic for mapping the queries to the virtual query and the technology for extracting the results of queries.