Measurements results reported in the literature indicate that the presence of people across the propagation link between a transmitter and a receiver could cause additional loss (of up to 20 to 30dB), as a result of body loss or multi-path interference due to body scattering.
In circumstances where the spatial density of TSs is high (as in the geometries investigated in ECC Report 131), the probability of TS-TS path blocking is also high, and hence the TS-TS path can no longer be treated as line-of-sight. Consequently, a path loss model with a greater exponent is more suitable than the free space path loss model for the characterisation of TS-TS links in dense hotspots.
In ECC Report 131, the mean path loss is characterised by a dual-slope model with a break point at 5 m. In addition, the log-normal distributed shadowing with standard deviations of 3 dB and 4 dB is assumed in ECC Report 131 for separations of less than 5 metres and greater than 5 metres respectively
Where the calculated path loss is less than free space attenuation for the same distance, the free space attenuation is used instead.