30 Delay spread relationship with the data collection threshold.
This plot shows two key points: first as antenna separation increases, so does RMS and secondly
as the threshold increases the delay spread increases. Notice the seemingly linear relationship that can
exist between both variables.
As was previously mentioned the relationship between RMS and path loss or distance was noticeable
and significant for the propagations measurements made in Hashemi paper. There is also evidence
to show that this relationship is insignificant or weak, thus supporting results published in other
studies.
In Figs. 3.31, 3.32, and 3.33, we provide a variety of curves from various measurement campaigns
taken throughout the world, such as USA, Canada, UK, Singapore, China, Japan, Korea, and the
Netherlands. Moreover, a wide range of carrier frequencies were investigated. What we do see is there
seems to be two groups of curves possibly due to the LOS and NLOS classification, as well as the
actual building construction material that varies across the world [26??“56].
WIRELESS MULTIPATH CHANNEL 141
Indoor RMS Delay Spread
0.1
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0.5
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0 20 40 60 80 100 120 140
RMS Delay Spread (nsec)
CDF (% < Abscissa)
a b
A B C D E F G
H I J K L
FIGURE 3.
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