Propagation of 450 MHz radio signals in a multi-floor building

Radio local area networks (R-LAN) and personal communication networks (PCN) operating in the frequency range from 300 MHz to 3 GHz proposed for indoor communications, have significant advantages over conventional telephone networks. Radio propagation inside a building is a complex phenomenon due to presence of a large number of randomly distributed reflectors, scatterers and movement of people which cause potentially severe signal losses. It becomes therefore imperative to understand the indoor channel. Many researchers have concentrated their study on indoor propagation in the 800-900 MHz and 1-2 GHz frequency bands. This paper reports on the measurements of the distance dependence of signal power at 450 MHz along the corridors of the first and second floors of a six floor building. We report in detail on the measurement procedures and also describe the environment where measurements are taken. A theoretical model for calculation of the distance dependence of the received signal power in LOS and obstructed LOS conditions is presented. With the help of this model and from measured-data, the values of the regression law "n", and the standard deviation are determined. A computer simulation tool using a 3D ray tracing technique for theoretical prediction propagation pattern of 450 MHz signals in the corridors is also discussed.