CALCULATION OF MEAN PATH LOSS AND SHADOWING

With one measurement approximately every 2 cm at a frequency of 3.5 GHz, the fast fading is captured. To extract the slow fading for calculation of mean path loss and shadowing, the fast fading was averaged through a sliding window of 40 wavelengths with successive windows overlapping by 30 wavelengths. An example of this process is shown in Figure 1 for the BS–MS link of route 6.

 

Figure 1: Example of BS–MS fast- and slow-fading along route 6, with RS at 5 m.

The shadowing on a wireless link is the signal fluctuations around the local mean level. For the purposes of this part, the local mean level will be obtained by fitting a least-squares regression curve to the data at each location and taking this as the mean path loss around which the shadowing fluctuations occur. For the BS–MS link, the data comprising all of the runs together will be treated as a single variable, but for the RS–MS link, the data collected at each different RS height will be treated separately. An example of the resulting shadowing distribution, on normal probability axes, so that a normal distribution with the same mean and variance as the actual data would be exactly a straight line. This is evidently a normally distributed variable, and calculation shows that it has zero mean and standard deviation of 3.5 dB. Similar distributions were found for the other routes and for the RS–MS link.