Hi koll,
I don’t think the downstream signal being better than upstream is necessarily true. It very much depends on your implementation and the schemes adopted for each. In many cases, the modulation schemes are different, so of course, the results are different. If you want to know the reason for a particular system, please attach the system file.
If the already allocated bandwidth is not enough, increasing it would boost the signal. Otherwise, it would cause more noise to be added to the signal and therefore the signal deteriorates.
Regards
.
