Conversion of CIR to CFR matrix, signal processing -- 2

Job ID: 34585982

Budget: ₹1,500 – ₹12,500 INR

Hello
I have a Channel Impulse Response matrix which is 4D and have to convert that to Channel frequency response matrix, i know it can be done by FFT but i need to know the relation between the two. You only need to explain few things, like how can i extract signal and others. There is no coding involved.
Thanks