Estimate indoor cell radius, cell area and AP count from EIRP, target RSSI, wall losses and a path-loss exponent.
The one-slope indoor model anchors path loss at a one-metre reference and then grows it by 10·N decibels per decade of distance. Solving it for distance at the point where received power equals the target RSSI gives the cell radius; multiplying the circle area by 0.65 accounts for overlap and non-circular real-world cells. Predictive designs live or die on the path-loss exponent and wall losses — assume free space indoors and you will deploy half the APs you need, then re-survey after go-live.
Coverage Heatmap
PL(d) = 20·log10(f_MHz) − 27.56 + 10·N·log10(d_m), inverted for d at a link budget of EIRP − target RSSI − wall losses − fade margin.
PL(d) = 20·log10(f_MHz) − 27.56 + 10·N·log10(d_m), inverted for d at a link budget of EIRP − target RSSI − wall losses − fade margin. The one-slope indoor model anchors path loss at a one-metre reference and then grows it by 10·N decibels per decade of distance. Solving it for distance at the point where received power equals the target RSSI gives the cell radius; multiplying the circle area by 0.65 accounts for overlap and non-circular real-world cells.
Predictive designs live or die on the path-loss exponent and wall losses — assume free space indoors and you will deploy half the APs you need, then re-survey after go-live.
This calculator takes 8 inputs: AP EIRP, Frequency, Target RSSI at the cell edge, Walls between AP and cell edge, Loss per wall, Shadow-fade margin, Path-loss exponent, Floor area to cover. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.