e.g.
[Fig 1]
(ref : gaussianwaves)
Let this is the PDP measured at the ESP32 as a receiver. If we move Access point further away , the P (blue line) should be at further time ( more right on x-axis) .
Now, I'm struggling with finding a way to obtain the Power Delay Profile from ESP32. Surely, I attached an external antenna to the ESP32 to enhance its signal precision.
First, I discovered that the Power Delay Profile (PDP) can be resulted from the Inverse fast Fourier transform (IFFT) of CSI data. But, the thing is the CSI that can be worked that way should be aligned in frequency domain so it can be turned into the time domain (PDP) . I coded with 'esp-idf' and obtain CSI data from callback function as many work does. Unfortunately, the CSI obtained from ESP32 is in subcarrier format and contains some null.
[Fig 2]
So, I need to convert ESP32 RAW CSI (Fig 2) (that is in subcarrier domain) to frequency domain CSI which can probably be done by some Frequency Matching algorithm. So , I posted this to ask if there is already a way to match subcarriers to frequency or to get a precise Power Delay Profile. May you share to be a big contribution to my work, please?