WLAN传感网络下的空气污染指数监测仿真

Monitoring and Simulation of the Air Pollution Index under WLAN Sensor Network

空气污染指数监测对于保护环境具有重要的意义。利用传统的WLAN网络进行空气污染指数监测,只能通过对采集得到的污染指数进行量化完成监测,但空气污染面积的无序扩大变化、空气透明度的非线性变化等污染指数,无法通过WLAN中的节点快速得到,节点需要一个均衡适应的过程,降低了空气污染监测的准确性。提出一种改进的基于WLAN的空气污染指数监测方法。利用无线访问接入点(AP)、移动测量端和定位处理器构建室外无线局域WLAN网,使待监测区域被三个或更多的AP信号覆盖,调整AP的发射功率消除监测盲区,计算采样点对所有AP边缘的概率密度,得到所有采样点的联合概率密度,根据计算结果获得采样点的准确坐标位置,不需要节点的适应过程,完成空气污染指数的监测。实验结果表明,利用改进算法能够对监测区域中的具体位置的空气污染物进行准确检测。

An improved air pollution index monitoring method based on WLAN is proposed. Wireless access points （AP）, mobile measuring terminal and location processor are used to build the outdoor WLAN, which makes the area prepared to monitor be covered by three or more AP signals. The transmission power of AP is adjusted to e- liminate the dead zone of monitoring. The probability density of the sampling points for all the edge of AP is calculated, and the joint probability density of all sampling points is got. According to the result of calculation, accurate co ordinate positions of sample points are obtained, in which the adaptation process of nodes does not need, so as to complete the air pollution index monitoring. The experimental results show that the improved algorithm can accurately detect the specific location of air pollutants in monitoring area.