A Study of Indoor Radio Propagation Channel Characteristics by Simulation

by

Ping Wang

M. Eng., 1995

Abstract

The design of Personal Communication Networks (PCNs) within buildings requires detailed knowledge of propagation properties on indoor radio channel. Indoor radio channels are variable in space and time, and are influenced by multipath signal fading and multipath delay spread. The data rate of indoor wireless network is limited by the multipath characteristics of the indoor radio channel, especially if an indoor radio network is to be incorporated in B-ISND using the vast information transport capacity offered by the Millimeter Wave frequency band. Multipath delay spread (multipath delay statistics) and multipath signal fading are very important factors to be considered in the design of high speed indoor wireless PCNs.

This thesis looks at the physical indoor environment in which PCNs would operate, and studies the extent and increase of static RMS delay spreads and relative received signal power in several different sizes of empty rooms and rooms with semi permanent partitions. It is shown that the maximum and mean value of static RMS delay spread linearly increase as the diagonal distance between ceiling and floor of a room increase. The RMS delay spread is independent of range between transmitter and receiver antenna. Using directive transmit antenna has shown the effect of reducing multipath signal fading in situations with short antenna separation. The RMS delay has larger variance in the case of using directive base station antenna. Temporal signal variations caused by human traffic moving around network terminal can be eliminated by using spaced antenna diversity, but the location of antennas needs to be chosen by aid of using software tools to ensure the acceptable diversity performance. Received signal variation is a function of transmitted signal bandwidth, this variation is less severe for greater transmitted signal bandwidth.

This thesis provides a developed simulation model and a software tool based on ray tracking techniques. The model can be effectively used to predict static RMS delay spread, relative signal power distributions in empty offices and rooms with dividers for different transmit antenna radiation patterns. The comparison of predicted static RMS delay spread with measurement results is present to support simulation results. A link budget  example based on simulated results is also shown to demonstrate the usefulness of the software.

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