ITU model for indoor attenuation

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The ITU indoor propagation model, also known as ITU model for indoor attenuation, is a radio propagation model that estimates the path loss inside a room or a closed area inside a building delimited by walls of any form. Suitable for appliances designed for indoor use, this model approximates the total path loss an indoor link may experience.

Applicable to/under conditions[edit]

This model is applicable to only the indoor environments. Typically, such appliances use the lower microwave bands around 2.4 GHz. However, the model applies to a much wider range.

Coverage[edit]

Frequency: 900 MHz to 5.2 GHz

Floors: 1 to 3

Mathematical formulations[edit]

The model[edit]

The ITU indoor path loss model is formally expressed as:

L \; = \; 20 \; \log f \; + \; N \; \log d \; + \; P_f(n) \; - \; 28

where,

L = the total path loss. Unit: decibel (dB).
f = Frequency of transmission. Unit: megahertz(MHz).
d = Distance. Unit: metre (m).
N = The distance power loss coefficient.
n = Number of floors between the transmitter and receiver.
Pf(n) = the floor loss penetration factor.

Calculation of distance power loss coefficient[edit]

The distance power loss coefficient, N is the quantity that expresses the loss of signal power with distance. This coefficient is an empirical one. Some values are provided in Table 1.[1]

Frequency band Residential area Office area Commercial area
900 MHz N/A 33 20
1.2 GHz N/A 32 22
1.3 GHz N/A 32 22
1.8 GHz 28 30 22
4 GHz N/A 28 22
5.2 GHz N/A 31 N/A
60 GHz N/A 22 17

Calculation of floor penetration loss factor[edit]

The floor penetration loss factor is an empirical constant dependent on the number of floors the waves need to penetrate. Some values are tabulated in Table 2.[1]

Frequency band Number of floors Residential area Office area Commercial area
900 MHz 1 N/A 9 N/A
900 MHz 2 N/A 19 N/A
900 MHz 3 N/A 24 N/A
1.8 GHz n 4n 15+4(n-1) 6 + 3(n-1)
2.0 GHz n 4n 15+4(n-1) 6 + 3(n-1)
5.2 GHz 1 N/A 16 N/A

Points to note[edit]

Further reading[edit]

  • Introduction to RF propagation, John S. Seybold, 2000, John Wiley and Sons.
  • Propagation data and prediction methods for the planning of indoor radio communication systems and the radio local area networks in the frequency range 900 MHz to 100 GHz, ITU-R Recommendations, Geneva, 2001.

See also[edit]

References[edit]

  1. ^ a b Propagation data and prediction methods for the planning of indoor radio communication systems and the radio local area networks in the frequency range 900 MHz to 100 GHz, ITU-R Recommendations, Geneva, 2001