That is indeed the only solution.
You can’t reduce the Gb traffic, because most of it is user-related traffic.
KS > You could check the ratio of “GMM & SM Signalling” vs “User Data”, to ensure that the amount of signalling isn’t too high. If you have a lot of GMM/SM signalling, then you must investigate which procedure is done too many times. (ATTACH/DETACH ? PDP CONTEXT ACTIVATION/DEACTIVATION ? ROUTING AREA UPDATE ?)
In some case, you can decrease the amount of signalling by adjusting some parameters.