Path Loss Exponent Estimation for Wireless Sensor Node Positioning: Practical Approach

Rapidly growing implementation of wireless sensor network technology demands accurate information about the location of the sensor node and it necessitates the improvement in the localization techniques for enhancing accuracy. Received Signal Strength Indicator is a widely used method which uses path loss exponent value for distance calculation. Path loss exponent value accounts for all the variations in the wireless communication channel parameters and hence, accuracy in path loss exponent calculation improves the overall accuracy of the localization process. The paper presents a practical approach for path loss exponent calculation using the RSSI method which is mathematically modeled using log-distance path loss model. It is observed that experimentally determined path loss exponent value for the indoor scenario consisting of obstructions in buildings is 4.2 which lies in the desired theoretical range of such a wireless environment which is 4 to 6. Error in the distance estimation is noted to be minimal when path loss exponent value is calculated in this way.