Determining required SNR for beat signal from ADI FMCW RADAR component

It's the chain:

Triangle frequency shape sent from ADF5901(24 GHz VCO and PGA with 2-Channel PA Output)

Then receive from

ADF5904(4ch 24GHz receiver downconverter) -> ADA8282(RADAR receiver path AFE: 4CH LNA & PGA) 

I have some next stage:

AD817(Op-Amp) summer of 4ch together -> AD817(Op-Amp) sallen-key filter -> Transmit to other board

Seems I need to start through PA power then add max distance noise to it, then noise of receivers chain through their datasheet. Then some MATLAB simulation to determine least possible SNR required?