Dear Li,
I think the best thing to do is to try to correlate OSRN with the dispersion and nonlinearity in the fiber (SPM, XPM). Eventually, these phenomena will affect the Q-factor. Unfortunately, there is no direct formula that correlate those parameters together. However, you may use AI to set some algorithms to get intelligence on these effects. You may contact me at ahmad.atieh@optiwave.com for further discussions.
Regards,
Ahmad