Estimate an indoor WiFi coverage radius with a log-distance path-loss model using transmit power, antenna gains, receiver sensitivity, frequency, environmental path-loss exponent, obstacles, and fade margin. The result provides a planning radius and approximate circular area for scenario comparison.
The result is a theoretical planning radius to the entered sensitivity threshold. Real usable coverage is irregular and must also meet capacity, interference, roaming, and uplink requirements.
This simplified model cannot replace a predictive design or on-site survey. Respect local transmit-power limits and use client-side capabilities, not access-point specifications alone.
At 20 dBm transmit power, 3 dBi transmit gain, 0 dBi client gain, −67 dBm sensitivity, 5 GHz, path-loss exponent 3, 8 dB obstacles, and 10 dB fade margin, estimated radius is 7.12 m, covering about 159 m² as a perfect circle.
Higher frequency produces greater free-space path loss at the same distance, all else equal, though antenna design, channel choice, and regulatory power also matter.
Use a value derived from measurements or a predictive model for the building. Open spaces and obstructed interiors can have materially different exponents.
No. Walls, doors, furniture, floor levels, and interference make real cells irregular. The circular area is only a geometric comparison.
Fade margin reserves signal strength for movement, multipath, changing obstacles, and modeling error instead of designing exactly at receiver sensitivity.
No. A location can have adequate signal yet insufficient airtime or throughput. Run a separate capacity model and validate both requirements.
| Input | Purpose |
|---|---|
| Transmit power | User-adjustable planning assumption |
| Transmit antenna gain | User-adjustable planning assumption |
| Client antenna gain | User-adjustable planning assumption |
| Receiver sensitivity | User-adjustable planning assumption |
| Frequency | User-adjustable planning assumption |