CHANNEL MODEL for INFOSTATIONS

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CHANNEL MODEL for INFOSTATIONS

• ? Our first measurements ?

Andrej Domazetovic, WINLAB April, 27
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• OUTLINE

• Reminder Friis free space equation
• Reminder Short range 2-ray propagation model
• Estimation of the Ricean K-factor
• Measurement 1 - fixed antennas
• Measurement 2 - one antenna moving

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• Friis free space equation

• The formula is a valid predictor for Pr for d
  which are in the far-field of the transmitting
  antenna - Fraunhofer region i.e. when inductive
  and electrostatic fields become negligible and
  only radiation field remains
• df2D2/? , dfgtgtD and dfgtgt?
• For fc 5.3 GHz and the antenna size D 7 cm
• df17.31 cm , df gtgt 7 cm and dfgtgt5.66 cm

(1)
Source Rappaport - Wireless Communications
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• Short range 2-ray propagation model

Source Rappaport - Wireless Communications
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Estimation of the Ricean K factor
Characterize the complex signal path gain of the
narrowband wireless channel as
Relate the equation to the two moments that can
be estimated from the measurements of received
power versus time
The second moment is the rms fluctuation of G
about Gtrue.
Source Greenstein et. al - Moment method
estimation of the Ricean K factor
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Estimation of the Ricean K factor
Under the assumption that the v(t) is complex
Gaussian, zero mean, this can be written as
If we can estimate the left-hand side of 1 and 2
from the data, then we have two equations with
two quantities that we need.
And finally, the Ricean K-factor is
Source Greenstein et. al - Moment method
estimation of the Ricean K factor
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Measurement 1 - Fixed antennas
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Results of measurements
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Results of measurements
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Results of measurements
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Measurement 2 - one antenna is moving
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Results of measurements
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Results of measurements
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Results of measurements