A17.18 ITU-R P.2109-0

This Recommendation provides a method for estimating building entry loss (additional loss due to one of the radio terminals being inside a building while the other is outside) at frequencies between about 80 MHz and 100 GHz.

The model makes no attempt to separate the loss suffered by a signal penetrating the exterior wall and the attenuation suffered in the path through the building. The buildings in this model fall into two distinct populations: where modern, “thermally-efficient” building methods are used (metallised glass, foil-backed panels) building entry loss is generally significantly higher than for “traditional” buildings without such materials. This classification, of “thermally-efficient” and “traditional,” refers purely to the thermal efficiency of construction materials. No assumption should be made on the year of construction, type (single or multi-floors), heritage or building method. For building entry loss, it is important to consider the thermal efficiency of the complete building (or the overall thermal efficiency). A highly thermally-efficient main structure with poorly insulated windows (e.g., single glazed with thin glass) can make the building thermally-inefficient and vice versa.

Table 1: Input parameters of ITU-R P.2109-0

The building entry loss distribution is given by a combination of two lognormal distributions. The building entry loss not exceeded for the probability, P, is given by:

\({L_{BEL}}\left( P \right) = 10{\rm{log}}\left( {{{10}^{0.1A\left( P \right)}} + {{10}^{0.1B\left( P \right)}} + {{10}^{0.1C}}\;} \right)\)  dB                                                                       (Eq. 1)

where:

                             \(A\left( P \right) = {F^{ - 1}}\left( P \right){\sigma _1} + {\mu _1}\)                   (Eq. 2)

                             \(B\left( P \right) = {F^{ - 1}}\left( P \right){\sigma _2} + {\mu _2}\)                   (Eq. 3)

                                                                   \(C =  - 3.0\)                                                         (Eq. 4)

                                                    \({{\rm{\mu }}_1} = {L_h} + {L_e}\)                                          (Eq. 5)

                                        \({{\rm{\mu }}_2} = w + x\;{\rm{log}}\left( f \right)\)                              (Eq. 6)

                                      \({{\rm{\sigma }}_1} = u + v\;{\rm{log}}\left( f \right)\)                            (Eq. 7)

                                      \({{\rm{\sigma }}_2} = y + z\;{\rm{log}}\left( f \right)\)                             (Eq. 8)

with:

\({L_h}\;\)being the median loss for horizontal paths, given by:

                \({L_h} = r + s\;{\rm{log}}\left( f \right) + t\;{\left( {{\rm{log}}\left( f \right)} \right)^2}\)      (Eq. 9)

\({L_e}\) being the correction for elevation angle of the path at the building façade:

                                              \({L_e} = 0.212{\rm{\;}}\left| \theta  \right|\)                                  (Eq. 10)

and

\({F^{ - 1}}\left( P \right)\) being the inverse cumulative normal distribution as a function of probability \(P\).

In Local Environments in the SEAMCAT’s GUI, the user can define the percentage of receiver and transmitter terminals that are indoor (see Figure 1). For those terminals that are indoors, the parameters of the building entry loss can be set by editing the Local Environment as shown in Figure 2. Note that the user can also set the percentage of traditional and thermally efficient buildings.

Figure 1: GUI of Local Environments in SEAMCAT.

Figure 2: GUI of ITU-R P.2109-0 for predicting building entry loss in SEAMCAT.