The mean path loss is characterised by a dual-slope model with a break point d_BP, an exponent of 2 for all distances less than d_BP, and an exponent of 3.5 otherwise. In short, the mean path loss, L, in dB is

(Eq. 243)

where d is the separation between the transmitter and receiver in kilometres, d_BP = 0.005 is the break-point in km (i.e. 5 m), and L_FS is free space path loss.

(Eq. 244)

where h_Tx and h_Rx are the height of the transmitter (Tx) and receiver (Rx) respectively and are expressed in m. d is the distance between the Tx and Rx and is expressed in km. f is the frequency and is expressed in MHz.

The log-normal distributed shadowing with the corresponding standard deviation is applied to the pathloss calculated.

This propagation model is used to calculate terminal-terminal interference and takes account of shadowing losses due to objects between the two terminals, but does not explicitly account for any loss from near-field objects, such as the person carrying the equipment.

Figure 477: GUI of the IEEE 802.11 Model C (modified)

Table 92: IEEE 802.11 Model C (modified) propagation model

Description	Symbol	Type	Unit	Comments
Variation	-	Boolean	-	Variation in path loss takes into account the uncertainty of building design, furniture, room size, etc.
Distance to break point	BP	Scalar	m
Log-Normal distribution before BP	-	Scalar	dB
Log-Normal distribution after BP	-	Scalar	dB

Browser not supported