Time delay spread and signal level measurements of 850 MHz radio waves in building environments

TLDR

The study measured 850 MHz time‑delay spread and signal levels on inside‑to‑outside paths at two homes and an office building. Root‑mean‑square time‑delay spreads reached up to 420 ns in residential settings, dropping below 325 ns when a direct path existed and to 100 ns at one residence; received power hovered around –40 dB relative to a 0.3 m reference, ranging from –40 to –80 dB in other cases, with median levels matching earlier continuous‑wave measurements and no significant polarization or floor‑level dependence.

Abstract

Time delay spread and signal level measurements of 850 MHz radio signals were made over inside-to-outside radio paths at two residential locations and an office building. Root mean square time delay spreads of up to 420 ns were encountered in residential environments. However, when a direct path was present, this improved to less than 325 ns overall, and even to 100 ns at one residence. Received power levels were around -40 dB, with respect to levels received at 0.3 m antenna separation, Under favorable conditions. In other cases, these relative levels varied from - 40 to - 80 dB. Median signal levels agreed well with continuous wave measurements made earlier at one site. No significant polarization dependence or floor level dependence were seen in these data.