How to calculate the wireless range in a building?

Question

Electronics

Hello. There was such a question, how to calculate the range of wireless communication in the room, in this case Zigbee. All inputs are known, such as transmitter power, receiver sensitivity, antenna gains.
But, everywhere I googling I meet calculations only according to the model of free propagation of waves. And here in the building. Which of the most (as for me close) found -tyk . Is this calculation acceptable in my case?

Answer 1

All inputs are known

Wall thickness?
Wall attenuation coefficient?
The angle at which the radiation falls on the wall?
Reflections from ceilings and floors?
Therefore, they probably don’t count, but based on experience they estimate, and then they select the locations and the amount of equipment at the place, even for DECT telephony, even for Wi-Fi, even for cellular repeaters, at least for something else similar

Answer 2

Panasonic's DEKT coverage area calculation uses the following method.
A couple of base stations are taken, then a handset is taken (there is an engineering series where you can see the signal strength and other useful information). And then zones with a strong/satisfactory/weak/bad signal level are plotted on the map of the premises, the optimal position for roaming between points is selected. Profit.
With other wireless networks, everything is about the same.