A17.13.2 Interpolation ambiguity

In parallel to the development of the JTG 5-6 plugins for CPG PTD, similar activities in SE42 (CEPT project team under WGSE closed in 2010) were on-going and in the course of the development of the plugins an ambiguity was found with respect to the interpretation of the interpolation between 100 m and 1 km and the 40 m to 100 m (see details in Doc. ECC/CPG11 PT-D(09)024).

Therefore, there was a need to develop two plugins to be made available based on the following figure:

Figure 480: Interpolation ambiguity (red: original WP3K/JTG 5-6/54, green: SE42 modification)

JTG56 (based on the WP3K/JTG 5-6/54 document) where the interpolation is between the local Hata and P1546_1km and where the loss is max of (interpolated value, free space)). This is equivalent to the red curve of the illustrative figure.
JTG56 (based on SE42 modification) is the same as above but with a modification to the interpolation as agreed in SE42 where the interpolation is made between max(hata,free space) and P1546_1km and loss is directly the interpolated value. Finally the loss is max (loss, free space). This is equivalent to the green curve of the illustrative figure above.

The selection between the two implementations is presented in the GUI of the JTG5-6 below:

Figure 481: GUI of the JTG5-6

Table 92: JTG 5-6 propagation model

Description	Symbol	Type	Unit	Comments
Variation				Variation in path loss
Allow reciprocity in the antenna height
Use the SE42 modification (Extended Hata instead of Free space for d<=0.1km)
General environment				Environment of the propagation: rural, suburban, urban.
Time probability [1% or 50%]				time probability: either 50 % or 1% for the interfering path (using P.1546 model)
Cut off distance [<100m]
User defined local clutter height