The mean path loss is characterised by a dual-slope model with a break point dBP, an exponent of 2 for all distances less than dBP, 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, dBP = 0.005 is the break-point in km (i.e. 5 m), and LFS is free space path loss.
(Eq. 244)
where hTx and hRx 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 standard deviations 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 | - | B | - | Variation in path loss takes into account the uncertainty of building design, furniture, room size, etc. |
Distance to break point | BP | S | m |
|
Log-Normal distribution before BP | - | S | dB |
|
Log-Normal distribution after BP | - | S | dB |
|