CSI deals with issues

[yjxb1]

Hello, I read your paper WiFi-based Human Activity Recognition usingRaspberry Pi. I have some doubts,I'm doing related work. In the preprocessing part of the data, I want to add low-pass filtering, but I don't know how to set the cutoff frequency, and I don't know what the filtered result should look like, which makes it impossible for me to judge. Are the filter parameter settings correct?