DW1000:RSSI from the data obtained by dwt_readaccdata

Hi all
I have a new question.
In User Manual, RSSI(RX Level) can be calculated by the equation in "4.7.2 Estimating the receive signal power ".
In this equation, “C = the Channel Impulse Response Power value reported in the CIR_PWR field of Register file: 0x12 – Rx Frame Quality Information”
However, I want to find the value of “C” using the data I calculated based on the IQ value obtained by dwt_readaccdata ().
Is this possible?
If possible, I think I need the change of equation in 4.7.2.
How should I change this equation?