An Experimental Study of Human Movement Effects on RSSI Levels in an Indoor Wireless Network

Abstract

Device-free localization (DFL) is the technology that monitors and analyzes the change of the received signal strength indicator (RSSI) level caused by human movement to locate the human position in a wireless network. Since human presence and movement in the communication link influences the RSSI level, most of the DFL techniques consider such effects as a major factor for position estimation. In this paper, the effect of human presence on the RSSI level at the different distances within/and nearby the wireless link is studied first. Then, the effect of human movement with different movement patterns on the RSSI level is investigated. Our experiments have been carried out in an indoor environment, a laboratory room, where a wireless network with 2.4 GHz, IEEE 802.15.4 technology has been employed. The experimental results show the characteristic of the average RSSI level when the human stands at each distance within the wireless network. In addition, real-time RSSI signals affected by human movement with different patterns are also demonstrated. Our findings are useful for understanding RSSI signal patterns, and designing more efficient DFL algorithms.