The EGN model (download EGN model paper) provides excellent accuracy in predicting the amount of non-linearity (or non-linear interference noise, NLI) affecting each channel in a WDM system.

See below the June 2014 news for more details. However, the EGN model is substantially more complex than the GN model. 

Three OptCom papers on non-linearity modeling and system impact have been accepted at ECOC 2014. They make use of the high-accuracy non-linear propagation EGN model to perform advanced studies of special system conditions. They can be dowloaded directly below.

The paper on the enhanced version of the GN model (the EGN model) is now available on Optics Express. The EGN model achieves excellent accuracy in predicting the power of non-linearity interference (NLI) that perturbs each transmitted channel. A version of the same paper that includes extended appendices on formulas derivations can be downloaded from arXiv: download paper with extended appendices from here. The EGN model has no limitations related to transmission format, Baud rate, channel spacing, number of channels, amplification type, span len