As this plot shows there is no significant difference of RMS between the two carrier frequencies
investigated. Figure 3.35 has the corresponding legend: A 850 MHz and B 1.9 GHz.
The next question concentrates on the relationship between delay spread and distance. There has
been an increasing body of literature showing there is a strong relationship. We will present some
propagation results revealing as the cell radius (or Tx-Rx distance) decreases, the RMS also decreases.
The following results are from St. Louis, Missouri and the Red Bank, NJ areas shown by the dashed
and solid lines, respectively [72].
Figure 3.36 shows, as the transmit and receive separation distance increases, the largest RMS value
increases. Lastly, these measured results were in the 1.9 GHz frequency band for the 20, 50, and 90%
CDF values.
144 CHAPTER THREE
Red Bank, NJ & St. Louis, MI
0
50
100
150
200
250
300
350
400
450
100 300 500 700
Distance (meters)
RMS Delay Spread
20% 50% 90% 20%
50% 90%
FIGURE 3.36 Delay spread statistics depending on distance.
The next question we wanted to answer had to do
with how the RMS delay spread varied from not only
country to country but also from one environment to
another.
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