View source for Physics:ITU model for indoor attenuation

The '''ITU indoor propagation model''', also known as ''ITU model for indoor attenuation'', is a [[Physics:Radio propagation model|radio propagation model]] that estimates the [[Path loss|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==

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

==Coverage==

[[Physics:Frequency|Frequency]]: 900 MHz to 5.2 GHz

Floors: 1 to 3

==Mathematical formulations==
===The model===

The ITU indoor path loss model is formally expressed as:

<math>L \; = \; 20 \; \log_{10} f \; + \; N \; \log_{10} d \; + \; P_f(n) \; - \; 28</math>

where,
:''L'' = the total [[Path loss|path loss]]. Unit: [[Physics:Decibel|decibel]] (dB).
:''f'' = [[Physics:Frequency|Frequency]] of transmission. Unit: [[Megahertz|megahertz]](MHz).
:''d'' = Distance. Unit: meter (m).
:''N'' = The distance power loss coefficient.
:''n'' = Number of floors between the transmitter and receiver.
:''P''<sub>f</sub>(n) = the floor loss penetration factor.

===Calculation of distance power loss coefficient===

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.<ref name="ITU_2">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</ref>

{|class="wikitable"
! Frequency band !! Residential area !! Office area !! Commercial area
|-
| 900&nbsp;MHz || N/A ||  33 || 20
|-
| 1.2–1.3 GHz || N/A || 32 || 22
|-
| 1.8–2.0 GHz || 28 || 30 || 22
|-
| 4&nbsp;GHz || N/A || 28 || 22
|-
| 5.2&nbsp;GHz || 30 (apartment), 28 (house) || 31 || N/A
|-
| 5.8&nbsp;GHz || N/A || 24 || N/A
|-
| 6.0&nbsp;GHz || N/A || 22 || 17
|}

===Calculation of floor penetration loss factor===

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.<ref name="ITU_2"/>

{| class="wikitable"
! Frequency band !! Number of floors !! Residential area !! Office area !! Commercial area
|-
| 900&nbsp;MHz || 1 || N/A || 9 || N/A
|-
| 900&nbsp;MHz || 2 || N/A || 19 || N/A
|-
| 900&nbsp;MHz || 3 || N/A || 24 || N/A
|-
| 1.8–2.0&nbsp;GHz || n || 4n || 15+4(''n''-1) || 6 + 3(''n''-1)
|-
| 5.2&nbsp;GHz || 1 || N/A || 16 || N/A
|-
| 5.8&nbsp;GHz || 1 || N/A || 22 (1 floor), 28 (2 floors) || N/A
|}

==Points to note==
==Further reading==

* ''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&nbsp;MHz to 100&nbsp;GHz, ITU-R Recommendations, Geneva, 2001.
* Propagation data and prediction methods for the planning of indoor radiocommunication systems and radio local area networks in the requency range 900 MHz to 100 GHz, Recommendation ITU-R P.1238-7, Geneva, 2012

==See also==

*[[Physics:Log-distance path loss model|Log-distance path loss model]]
*[[Physics:Radio propagation model|Radio propagation model]]
*[[Physics:Young model|Young model]]

==References==
<references/>

[[Category:Radio frequency propagation]]

{{Sourceattribution|ITU model for indoor attenuation|1}}