914 MHZ PATH LOSS PREDICTION MODELS FOR INDOOR WIRELESS COMMUNICATIONS IN MULTIFLOORED BUILDINGS

Quantitative models are presented that predict the effects of walls, office partitions, floors, and building layout on path loss at 914 MHz. The site-specific models have been developed based on the number of floors, partitions and concrete walls between the transmitter and receiver, and provide simple prediction rules which relate signal strength to the log of distance. The standard deviation between measured and predicted path loss is 5.8 dB for the entire data set, and can be as small as 4 dB for specific areas within a building. Average floor attenuation factors (FAF), which describe the additional path loss (in decibels) caused by floors between transmitter and receiver are found for as many as four floors in a typical office building. Average floor attenuation factors are found to be 12.9 and 16.2 dB for one floor between the transmitter and receiver in two different office buildings. For same-floor measurements, attenuation factors (AF) are found to be 1.4 dB for each cloth-covered office partition and 2.4 dB for each concrete wall between transmitter and receiver. Path loss contour plots for measured data are presented. In addition, contour plots for the path loss prediction error indicate that the prediction models presented in this paper are accurate to within 6 dB for a majority of locations in a building.