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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 m and greater than 5 metres m respectively.
Where the calculated path loss is less than free space attenuation for the same distance, the free space attenuation is used instead.