Measurements of 800-MHz Radio Transmission Into Buildings With Metallic Walls

Abstract

In this paper we describe an experiment conducted to measure 800-MHz attenuation into buildings. This information is needed for refining the configuration and design of portable radiotelephone systems that will accommodate low-power portable sets. Signal levels have been measured in and around three small buildings and a house, using an instrumentation van with an erectable 27-foot-high antenna. These buildings and the house all have metallic materials in their walls and thus are expected to exhibit high attenuation. The van was parked at one location with respect to the three buildings, and at nine different locations, at distances ranging from 400 feet to 1600 feet, from the house. We found that small-scale signal envelope variations are approximately Rayleigh distributed. For the house, large-scale distributions of the small-scale signal medians are approximately log-normal. Median signal levels outside the house decrease as d <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−4.5</sup> , where d is the distance from the van. Inside the house, levels decrease as d <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3.9</sup> for first-floor locations and as d <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−3.0</sup> for second-floor locations. Average signal levels at 1000 feet, relative to free space, are −12.5 dB outside, −18.5 dB for the first floor, −16.5 dB for the second floor, and −28.9 dB for the basement. Other statistics of the signal levels and of attenuation into the house are also given in the paper. Cross-polarization couplings of −10 dB to 0 dB were measured in and around the three small buildings. The small-scale signal medians inside the three buildings range from 2 dB above to 24 dB below the averages of the signal medians outside buildings.