th 120 MHz transformer station. Delay spreads and BER were de- and eight-element uniform linear arrays were used at both termined from about 120,000 snapshots, the majority of ends. The data was tested for WSS by means of a power them taken on the petrochemical plant. As the equip- correlation metric on the power delay profiles, averaged ment had a higher transmit power than usual Bluetooth over all 64 SISO links. The threshold for the correlation appliances, the impulse responses could be clipped at 30 coefficient with respect to measurement time was arbi- dB instantaneous dynamic range during processing. The trarily set at 0.75; all data passed. Typical values for average delay spread on the petrochemical plant was 38 temporal dispersion were 25 ns mean excess delay and 41 ns, that on the transformer station 88 ns, and on the car ns RMS delay spread. The measured channel was slowly park 76 ns. The variance of the results on the car park was varying with time, with the maximum observed Doppler two orders of magnitude higher than of those on the shift around 1.5 Hz. The angular dispersion was smaller other environments. The authors attribute this to the 20:00 22:00 10:00 Figure 4.7-44 Total wideband power (upper curve) and time-varying power (lower curve) during night time (after [MeBH04]). Propagation modelling and channel characterisation CHAPTER 4.7 Distance from entrance (m) Distance from entrance (m) (a) Angular spread. (b) Delay spread. Figure 4.7-45 Angular and delay spread in excitation zone behind tunnel entrance for three different Tx elevations: 15 °, 30°, and 45° (solid, dashed, and dotted). Tunnel entrance at 0 m; vertical lines indicate end of respective excitation zones (after [MoRJL03]). presence of two distinctly different reflective processes, using measurements of past and present behaviour. those of the cars in the direct vicinity, measured in Predicting fading behaviour has promising applications in metres, and those of the buildings at about 100 m dis- controlling relatively simple combining