114 lines
3.2 KiB
Plaintext
114 lines
3.2 KiB
Plaintext
@node Propagation Loss Models
|
|
@chapter Propagation Loss Models
|
|
@anchor{chap:propagation-loss-models}
|
|
|
|
This chapter describes validation of ns-3 propagation loss models.
|
|
|
|
@section FriisPropagationLossModel
|
|
|
|
@subsection Model reference
|
|
|
|
From source: @uref{http://www.scribd.com/doc/6650712/Wireless-CommunicationsPrinciples-and-Practice-Theodore-S,, Wireless Communications-Principles and Practice ,Theodore S Rappaport pg. 71 }
|
|
|
|
Given equation:
|
|
@smallformat
|
|
@verbatim
|
|
Pr = Pt*Gt*Gr*lmb^2/((4*pi)^2*d^2*L)
|
|
|
|
Pt = 10^(17.0206/10)/10^3 = .05035702
|
|
Pr = .05035702*.125^2/((4*pi)^2*d*1) = 4.98265e-6/d^2
|
|
|
|
bandwidth = 2.2*10^7
|
|
m_noiseFigure = 5.01187
|
|
noiseFloor = ((Thermal noise (K)* BOLTZMANN * bandwidth)* m_noiseFigure)
|
|
noiseFloor = ((290*1.3803*10^-23*2.2*10^7)*5.01187) = 4.41361e-13W
|
|
no interference, so SNR = Pr/4.41361e-13W
|
|
|
|
Distance :: Pr :: SNR
|
|
100 4.98265e-10W 1128.93
|
|
500 1.99306e-11W 45.1571
|
|
1000 4.98265e-12W 11.2893
|
|
2000 1.24566e-12W 2.82232
|
|
3000 5.53628e-13W 1.25436
|
|
4000 3.11416e-13W 0.70558
|
|
5000 1.99306e-13W 0.451571
|
|
6000 1.38407e-13W 0.313591
|
|
@end verbatim
|
|
@end smallformat
|
|
|
|
@subsection Validation test
|
|
|
|
Test program available in ns-3 at @code{src/devices/wifi/propagation-loss-model-test-suite.cc}
|
|
|
|
Taken with values (lambda = 0.125m for 802.11b at 2.4GHz, SystemLoss = 1):
|
|
@smallformat
|
|
@verbatim
|
|
Distance :: Pr
|
|
100 4.98265e-10W
|
|
500 1.99306e-11W
|
|
1000 4.98265e-12W
|
|
2000 1.24566e-12W
|
|
@end verbatim
|
|
@end smallformat
|
|
|
|
@subsection Discussion
|
|
|
|
As can be seen, the received power outputted from the model, and the power
|
|
computed from the source's equation are identical. The test suite tests
|
|
the expected value to the most significant digit of the input expected value.
|
|
|
|
@section LogDistancePropagationLossModel
|
|
|
|
@subsection Model reference
|
|
|
|
From source: @uref{http://www.plextek.co.uk/papers/aps2005mcw.pdf,, Urban Propagation Measurements and Statistical Path Loss Model at 3.5 GHz, Marcus C. Walden, Frank J. Rowsell}
|
|
|
|
Given equation:
|
|
@smallformat
|
|
@verbatim
|
|
PL{dBm} = PL(d0) + 10*n*log(d/d0) + Xs
|
|
|
|
PL(1) from friis at 2.4GHz: 40.045997dBm
|
|
PL{dBm} = 10*log(.050357/Pr) = 40.045997 + 10*n*log(d) + Xg
|
|
Pr = .050357/(10^((40.045997 + 10*n*log(d) + Xg)/10))
|
|
|
|
bandwidth = 2.2*10^7
|
|
m_noiseFigure = 5.01187
|
|
no interference, so SNR = Pr/4.41361e-13W
|
|
@end verbatim
|
|
|
|
taking Xg to be constant at 0 to match ns-3 output:
|
|
@verbatim
|
|
Distance :: Pr :: SNR
|
|
10 4.98265e-9 11289.3
|
|
20 6.22831e-10 1411.16
|
|
40 7.78539e-11 176.407
|
|
60 2.30678e-11 52.2652
|
|
80 9.73173e-12 22.0494
|
|
100 4.98265e-12 11.2893
|
|
200 6.22831e-13 1.41116
|
|
500 3.98612e-14 .090314
|
|
1000 4.98265e-15 .011289
|
|
@end verbatim
|
|
@end smallformat
|
|
|
|
@subsection Validation test
|
|
|
|
Test program available in ns-3 at @code{src/devices/wifi/propagation-loss-model-test-suite.cc}
|
|
|
|
Taken at default settings (exponent = 3, reference loss = 46.6777, 802.11b at 2.4GHz)
|
|
@smallformat
|
|
@verbatim
|
|
Distance :: Pr
|
|
10 4.98265e-9
|
|
20 6.22831e-10
|
|
40 7.78539e-11
|
|
80 9.73173e-12
|
|
@end verbatim
|
|
@end smallformat
|
|
|
|
@subsection Discussion
|
|
As can be seen, the received power outputted from the model, and the power computed from the source's equation are identical. The test suite tests
|
|
the expected value to the most significant digit of the input expected value.
|
|
|