Research On Wireless Sensor Networks And Its Design In Emergency Environmental Monitoring

With the rapid development of industrial and agricultural production and economic construction, the environmental pollution accident, especially paroxysmal pollution accident, has an increasing trend both in number and extent of jeopardize. Emergency monitoring of paroxysmal pollution accident requires that the monitoring data can be collected and transferred promptly and effectively so that the department concerned is able to cope with the accidents immediately. It is becoming a badly needed problem to build an efficient environmental monitoring system for society.Compared to the traditional wired transmission networks, Wireless Sensor Networks (WSN) has the advantage of laying convenience, strong mobility, stability and security of the data transmission, which can achieve the task of date collection, transmission and handling effectively. We introduce relevant knowledge about WSN, especially the simulation of different routing protocol according to the domestic and international literature. Besides, we design an emergency environmental monitoring system based on the characteristics of emergency environmental monitoring. The major work and results are as follows:(1) We design a WSN node which is suitable for emergency environmental monitoring which takes C8051F340 and XBee-PRO as main-control chip and transmission module in the hardware. WSN is built by ZigBee. Performance evaluation is down from bit error rate, packet delay, the distance of transmission and energy consumption. Experimental results show that the node has less bit error rate and energy consumption. The node has the advantages in the distance of transmission to make up the defect of energy consumption, which meets the needs of emergency environmental monitoring.(2) Demand routing and proactive routing are two most classic routing protocols in WSN, and the differences between them are whether they can actively maintain routing tables. We gain insights into DSDV, DSR and AODV and the experimental results show that DSR and AODV are more suitable for dynamic network topology and large-scale network environment. Besides, as the combination of the other two, AODV is more suitable for emergency environmental monitoring.(3) In need of emergency environmental monitoring system, we develop a data collection center of pollution source, which realize the functions of pollution source data collection, uploading, processing and display. Via placing a number of device nodes around the building, we collect several environmental variables such as TVOC, formaldehyde, sulfur dioxide and oxygen in real-time.With the development of WSN, the advantage will be continuously displayed in different fields. It is a promising subject to apply WSN to the emergency environment monitoring which will solve the increasingly serious pollution problems.