MULTI-FREQUENCY RADIOWAVE PROPAGATION MEASUREMENTS IN THE PORTABLE RADIO ENVIRONMENT

摘要

Time delay spread and signal level measurements were made in two dissimilar office buildings at 850 MHz, 1.7 GHz and 4.0 GHz. No significant statistical difference in time delay spread was found at the three frequencies. The maximum rms time delay spread at the three frequencies did not exceed 270 nanoseconds at the larger building and 100 nanoseconds at the smaller building. Attenuation, while very nearly the same at the three frequencies, decreased slightly with increasing frequency, within the limits of the experiment's accuracy. The variation of the received signal level with distance could be characterized by free space propagation together with attenuation per unit distance.This attenuation coefficient decreased slightly with increasing frequency. The fractional error was found to be a useful measure of the spread of the data.