RSSI based position estimation in ZigBee sensor networks

Localization in wireless sensor networks is getting more and more important in the recent years, since many applications need to locate the source of incoming measurements as precise as possible. Channel propagation and path loss modelling is the key point in successful position estimation. In this thesis, most popular distance estimation and position estimation methodologies are discussed, as well as the indoor channel models developed so far are presented. A ZigBee based RSSI (Received Signal Strength Indicator) measurement system is designed to collect path loss data with varying distances between the transmitter and the receiver. An empirical indoor channel model for ZigBee sensor networks is developed based on the path loss measurements, and implemented with the discussed position estimation methodologies. Not only the developed path loss model, but also the presented position estimation methodologies are evaluated numerically via simulations.