RSSI-based Localization in an Emulated Active RFID System

Distance estimation and localization based on Received Signal Strength Indicator is the most popular approach used in wireless sensor networks because of its simplicity and low-cost implementation. A complementing system to WSN is the radio-frequency identification system which also uses RSSI. In this paper, the principle of localization technique is evaluated in an RFID system using a design of experiment. In a virtual environment setup, ranging test and localization test is done by using tag properties and RSSI readings to determine the location of the tag and the corresponding distance error. The use of an active RFID system emulated environment with readers and tags deployed in a 2D space proved that RSSI based distance estimation is linear in short range and unstable in long range with distance variance of 1.33m. It is also demonstrated that additional RFID readers used as reference for distance estimation give smaller localization error of 0.43m than using only one reader with an error of 1.07m. The experiment shows how RSSI can be unreliable in distance estimation, hence, elevates the need for more accurate localization algorithms.