The authors present the results of average and impulsive noise measurements inside several office buildings and retail stores. The noise measurement system operated at 918 MHz, 2.44 GHz, and 4 GHz with a nominal 40-MHz, 3-dB RF bandwidth. Omnidirectional and directional antennas were used to investigate the characteristics and sources of RF noise in indoor channels. Statistical analyses of the measurements are presented in the form of peak amplitude probability distributions, pulse duration distributions, and interarrival time distributions. Simple first-order mathematical models for these statistical characterizations are also presented. These analyses indicate that photocopiers, printers (both line printers and cash register receipt printers), elevators, and microwave ovens are significant sources of impulse noise in office and retail environments.< >

Results of delay spread and path loss measurements across a large college campus are presented. Two line-of-sight links were used with three different types of antennas to determine best polarizations and pointing angles. Measurements show multipath is most severe when antennas of different polarizations are used on each end of the link. Minimum delay spreads are encountered when antennas of the same polarization are used and pointed directly toward each other. As long as polarizations are matched on each side of the link, polarization does not have significant impact on delay spread or path loss. However, circularly polarized helical antennas offer multipath reduction over a wide range of pointing angles. This suggests that on point-to-point cross-campus links where a single antenna is desired to serve a broad coverage area, circular polarization could be used in lieu of channel equalization to improve bit error rates in high-speed data networks.<<ETX>>

Results of wideband path loss and delay spread measurements for two representative microcellular environments in the San Francisco Bay area in the 1900 MHz band are presented. The results provide insight into the statistical distributions of measured path loss by showing the validity of a double regression model with a break point at a distance that has first Fresnel zone clearance for line-of-sight topographies. The variation of delay spread as a function of path loss is investigated, and a simple exponential overbound model is developed. The path loss and delay spread models are then applied to communication system design allowing outage probabilities, based on path loss or delay spread, to be estimated for a given microcell radius.<>

The impact of surrounding buildings on path loss and multipath delay spread for personal communication services (PCS) operating inside buildings is studied. Measurements concluded inside three large office buildings in the San Francisco Bay are provide an extensive database for propagation models at 915 MHz and 1900 MHz, and show variability in path loss and delay spread caused by multiple floors between communication terminals, and multipath scattering from surrounding buildings. Quantitative models provide prediction of the propagation effects caused by surrounding buildings for wireless personal communications system design

The authors describe average and impulsive noise measurements inside several office buildings and retail stores. The receiver had a 70 dB dynamic range and operated at 918 MHz, 2.44 GHz, and 4.0 GHz with a nominal 40 MHz 3 dB RF bandwidth. Omni-directional and directional antennas were used to investigate the characteristics and sources of RF noise in indoor channels. Statistical analyses of the measurements are presented in the form of noise level distributions, amplitude probability distributions, pulse duration distributions, and interarrival time distributions. These analyses indicate that photocopiers, printers (line printers and cash register receipt printers), elevators, and microwave ovens are significant sources of impulsive noise in office and retail environments