Statistical evaluation of the influence of irregularities of reflecting surfaces at the planning of WLAN indoors

Planning and maintenance of WLAN includes continuous monitoring of the signal level throughout the volume of the coverage area. Simulation methods of frequency planning and territorial planning based on ray tracing of signals are widely used for this purpose. The main limitation of these methods is the smooth approximation of reflecting surfaces in a room. A method of accounting irregularities of the walls and floors of the building is proposed in this paper. Statistical evaluation of the influence of irregularities of reflecting surfaces is obtained by the random variation of the coordinates that define the position of the planes in space. It is shown that the arithmetic mean of the signal is not more than 5 % different from the deterministic experience in case of the irregularities of up to two wavelengths. A distribution law of the WLAN transfer ratio module is very close to the normal law in the shadow area only.