Final report on link level and system level channel models - Winner

WINNER D5.4 v. 1.4
5.6 Interpretation of results
5.6.1 Path-loss
5.6.1.1 Scenario A1
5.6.1.1.1 Proposed path-loss model
The results for path loss and shadowing have been summarized in Table 5.45.
Table 5.45: Path-loss and shadowing characteristics in the indoor environment.
Indoor LOS (c-c) NLOS (r–c)
PL at 5.25 GHz
SF standard deviation at
5.25 GHz
46.8 +18.7 log10(d),
d >1m
s = 3.1 dB
PL (d)= 38.8+36.8 log10(d)
d >5m
s = 3.5 dB
5.6.1.1.2 Probability of LOS
The probability of line-of-sight (LOS) propagation vs. distance is a function we denote the pLOS
function. For scenario A1, this characteristic can be derived analytically because the geometry of the
scenario is known exactly.
A simple ad-hoc fit of the derived pLOS function is given as:
p LOS (d) = 1 – (1 – x 3 ) 1/3 * (1 – 5 / 50), (5.55)
where x = 1 - log 10 (d / 2.5) / log 10 (100 / 2.5).
5.6.1.2 Scenario B5a
We use the path-loss model of [PT00] as given below. We assume that it is applicable from 30 meters to
2km distance with a correction term for frequency, i.e.
( fc
/ 2.5GHz) + 23.5log10( d + δ
slow
Loss = 36 .5 + 20log10
) , 300 m < d < 8 km (5.56)
We note that for the 30m to 300m range (for which [PT00] presents no measurements), the path-loss
model almost coincides with cases in [Dug99] with the smallest path-loss. These cases are probably the
ones with the least obstructed LOS. The model of [PT00] is for 2.5GHz. For other centre-frequencies, fc,
it seems reasonable to translate by using the free-space frequency dependence as the propagation scenario
(e.g. path-loss exponent) is close to free-space propagation.
The shadow fading is Gaussian with mean zero and standard deviation σ SF = 3.4 dB based on [PT00].
5.6.1.3 Scenario B5b
Based on the observation of numerous papers that the path loss follows approximately a free-space law
before the breakpoint distance we will assume that loss is given by
Loss
( r) = −20log( /( 4πr)
) + σ free + δ free,
r ≤ rb
λ , d < 1 km (5.57)
where the first part is recognized as the free-space path-loss, d free is a Gaussian distributed random
variable (shadow fading), with standard deviation s free = 3 dB. This path-loss model (i.e., (4.10)) can be
used for a maximum distance of 1 km. Many measurements seem to show path loss lower than the freespace
before the breakpoint and indeed it can happen due to constructive multi-path. However, to avoid
producing overly optimistic results the extra loss s free has been introduced such that the probability of a
lower than free-space loss is only some 14%. The breakpoint distance is calculated as
( h − h )( h − h )
b 0 b 0
rb = 4
(5.58)
λ
where we, somewhat pessimistically, set the effective ground level h0
to 1.6 meter. For distances larger
than r b we set the path loss to
Loss
( r) = free − 20log10( λ /( 4πrb
)) + 40log( r / rb ) + δ beyond,
r > rb
σ , (5.59)
where the first two teRMS correspond to the (mean) path-loss at b
r and d beyond is a Gaussian shadowfading
term with mean zero and standard deviation 7 dB.
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