Root Mean Square Delay Spread (RMS Delay Spread)

A statistical measure of multipath delay dispersion defined as the root‑mean‑square of excess delays weighted by received power. Given a power delay profile p(τ), define mean delay τ̄ = (∫ τ p(τ) dτ)/(∫ p(τ) dτ) and RMS delay spread τ_rms = sqrt[(∫ (τ − τ̄)^2 p(τ) dτ)/(∫ p(τ) dτ)].