Log-distance path loss (log-normal shadowing) — model, PLE, and formula
Log-distance / log-normal shadowing path loss: formula beyond Friis, path-loss exponent by environment, shadowing χ, and how it extends free-space models.
propagation path model
Friis free-space path loss — formula, assumptions, and dB form
Friis transmission equation and free-space path loss: $latex (4\pi d/\lambda)^2$, dB form, assumptions, and when to move to log-distance or two-ray models.