By Maher Harb, Comcast Jude Ferreira, Comcast Larry Wolcott, Comcast Belal Hamzeh, Comcast Kang Lin, Comcast Jon-En Wang, Comcast
This technical paper focuses on four topics related to the prediction, detection, and mitigation of amplifier non-linearities. First, reviewing the fundamental theory behind the phenomenon alongside examples obtained from lab measurements. Second, introducing a method for detecting amplifier nonlinearity based on measuring the distortion noise from a cable modem’s full band capture (FBC). Third, introducing data analysis performed across the entire virtualized cable modem termination system (vCMTS) footprint to inform deployment priority groups such that spectrum activation proceeds on nodes where the risk of encountering amplifier nonlinearity is lowest. Finally, presenting a statistical model for the prediction of amplifier non-linearity based on features derived from the FBC, RxMER, and expected change in spectrum utilization post-2nd OFDM deployment.