A Unified Geolocation Channel Model--Part II (Multi-path Distribution)

Indoor geolocation systems have emerged and have attracted a wide audience recently. There are three important components that constitute an indoor geolocation system: (1) transmitter, (2) receiver, and (3) indoor channel model. To some extent the primary transmitter design requirements are transmit power and a frequency or a set of frequencies of operation. The receiver is designed to operate at a certain distance from the transmitter and at the same frequency or set of frequencies of operation. Hence, any indoor channel model must take into account these two important design requirements. The indoor channel is perhaps very intriguing because multipath is ubiquitous due to high signal scattering, reflection, and refraction. It is been widely accepted in the literature that the two primary channel effects are (1) path loss and (2) multipath distribution. First, the path loss model is currently accepted to be a function of the transmitter and receiver geometry and frequency of operation. Second, the most widely used and accepted indoor channel multipath distribution models are Rayleigh, Rician, and lognormal. As indicated in the paper the Rayleigh distribution is wider than Rician and Rician is wider than lognormal. This implies that the Rayleigh fading channel is the most severe and Rician fading is more severe than lognormal and lognormal is the least severe channel. Unfortunately, the dependency of the path factor on the frequency of operation in the context of a unified channel model is overlooked in the literature.