Formulation and Experimental Verification of Distance vs RSSI for Localization in Wireless Sensor Network

Abstract

Wireless Sensor Networks (WSN) is getting interest for its remarkable application in different sectors like in defense for target tracking, monitoring environmental and animal activities, medical treatment etc. In WSN nodes collect data from deployed area and then send it to the center node for further processing. So localization is an important issue in sensor network to locate the position from where the data is receiving to central node. Distance to sensors estimated through several techniques. Among those techniques, Received Signal Strength Indicator (RSSI) method is simple, inexpensive, required no extra hardware like Global Positioning System (GPS). In RSSI technique, the distance between nodes is determined using RSSI value. So path loss model is necessary to establish a relation between RSSI and distance. However radio wave propagation can be affected by different factors like floor, wall, ground, external interference due to WLAN, human body, temperature etc. in the real environment. To get the exact RSSI vs distance curve the accurate propagation model considering different factors exists in the real environment is needed. In this project work, different factors which have the effect on radio wave propagation both in indoor and outdoor environment has been tested experimentally. The experimental data is compared with the theoretical model data and it is observed that the basic propagation model does not cover all the factors. So a new factor is added to the basic path - loss model to compensate the losses due to different factors exist in real environment in where sensors are deployed. After addition of new factor which consider the other attenuation factors in real environment with the basic propagation model it is shown that the proposed propagation model yields the result near to the practical data.