A17.21.1 Description of the model

This path loss model was developed by 3GPP and its detailed description can be found in [1]. The model is applicable for link and system level simulations in the frequency band 0.5–100 GHz, for bandwidths up to 10% of the center frequency but not larger than 2 GHz, and for urban macro cell (UMa), urban micro cell street canyon (UMi-Street canyon), rural macro cell (RMa), and indoor office. Note that only outdoor scenarios UMa, UMi-Street canyon, and RMa are implemented in SEAMCAT. 3GPP TR 38.901 is an empirical path loss model based on measurements and it is to a large extent aligned with earlier empirical path loss models valid below 6 GHz, such as IMT-Advanced model ITU-R M.2135. The model supports LOS and NLOS propagation conditions as well as the LOS probabilities. This model includes clutter loss and as such it is not to be combined with the clutter loss model of Recommendation ITU-R P.2108-0.

Table 1: 3GPP TR 38.901 Path Loss model

Note 1:

Breakpoint distance where fc is the centre frequency in Hz, c=3×108 m/s is the propagation velocity in free space, and hBS' and hMS' are the effective antenna heights at the BS and the MS, respectively. The effective antenna heights hBS' and hMS' are computed as follows: hBS'=hBS-hE, hMS'=hMS-hE, where hBS and hMS are the actual antenna heights, and hE is the effective environment height. For UMi, hE=1 m. For UMa, hE=1 m with a probability equal to and chosen from a discrete uniform distribution uniform (12,15,…,(hMS-1.5)) otherwise.

With C(d2D, hMS) given by;

Note that hE depends on d2D and hMS and thus needs to be independently determined for every link between BS sites and MSs. A BS site may be a single BS or multiple co-located BSs.

3-D distance is defined as:

Note 2:
fc denotes the center frequency normalized by 1 GHz, all distance and height related values are normalized by 1 m, unless it is stated otherwise.

Note 3:
UMa NLOS pathloss is from TR 36.873 with simplified format and PLUMa-LOS is equal to pathloss of UMa LOS outdoor scenario.

Note 4:
PLUMi-LOS is the pathloss of UMi-Street Canyon LOS outdoor scenario.

Note 5:
Break point distance dBP=2πhBShMSfc/c, where fc is the centre frequency in Hz, c=3×108 m/s is the propagation velocity in free space, and hBS and hMS are the antenna heights at the BS and the MS, respectively.

SEAMCAT specific implementation:

Table 2: LOS Probability

Note: The LOS probability is derived assuming antenna heights of 3 m for indoor, 10 m for UMi and 25 m for UMa.

In case the LOS probability is used, the path loss is computed as follows:

for a given Tx-Rx distance d:

compute probability of LoS:
draw a sample value from uniform distribution
if the path is LoS:

else the path is NLoS:

where path losses in the LOS and NLOS conditions ( and ) and the LOS probability, , for a given scenario are shown in Table A.17.19.1 and Table A.17.19.2, respectively.

A17.20.2 Input parameters

The input parameters for the path loss model 3GPP TR 38.901 are shown in Figure 1 and defined in Table 3.

Figure 1: GUI of the 3GPP TR 38.901 path loss model

Table 3: Parameters of the 3GPP TR 38.901 Path loss model

Description	Symbol	Type	Unit	Comments
Variation	σSF	B	dB	Variation in path loss (applies shadow fading)
Scenario	-	S	-	Urban Macro Cell (UMa), Urban Micro Cell-Street canyon (UMi-Street canyon), or Rural Macro Cell (RMa)
Line of Sight	-	S	-	Line of Sight (LOS), Non-Line of Sight (NLOS), or LOS Probabilities
Street width	W	D	m	Average street width for RMa scenario
Building height	h	D	m	Average building height for RMa scenario

References

[1]	3GPP, "TR 38.901 5G; Study on channel model for frequencies from 0.5 to 100 GHz," 2018.

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