Reference Tag - based Indoor Localization Techniques ?

In WSN-based localization, there are many challenging points. The difficulty lies in the fact that communication signals in a space-limited indoor office environment are interfered and attenuated by multi-path, reflection, channel fading, deflection, diffraction, etc. In fact, it is quite difficult to develop a reliable signal propagation model in an office environment because it is challenging to accurately estimate the signal path loss parameter. This paper proposes using reference tags for online estimation of signal propagation model and for the reliable calculation of the time of flight of radio signals. Thus main contribution of this paper is to suggest localization schemes based on reference tag, which is so-called reference tag-based indoor localization (RTIL).