Description
The Power Delay Profile is the squared magnitude of the channel impulse response, |h(τ)|², as a function of propagation delay τ. PDP is reconstructed from CSI by an inverse Fourier transform across subcarriers and reveals discrete multipath taps — direct path, reflections, late scatterers. PDP-based features are the most physically interpretable CSI representation: each tap is a candidate scatterer whose energy and delay reveal the room geometry.
When it's used
- Multipath-aware CSI sensing (delay-domain features)
- LOS / NLOS classification from PDP shape
- Indoor channel-model validation
- Sub-tap-resolution time-of-arrival estimation
Limitations
- Resolution bounded by Wi-Fi bandwidth (~26 ns at 40 MHz, ~5 ns at 160 MHz)
- Requires phase-clean CSI
- Multipath taps blur into each other in cluttered rooms