4 ms·
> Don't forget that the QAMs can go pretty high, 128/256 points iif the SNR is sensible. Isn't 4096-QAM already pretty commonplace these days? For example DOCS
by zokier 3y ago
> Don't forget that the QAMs can go pretty high, 128/256 points iif the SNR is sensible.
Isn't 4096-QAM already pretty commonplace these days? For example DOCSIS is apparently pushing already 16k QAM:
> DOCSIS 3.1 adds 16-QAM, 128-QAM, 512-QAM, 1024-QAM, 2048-QAM and 4096-QAM, with optional support of 8192-QAM/16384-QAM.
https://en.wikipedia.org/wiki/DOCSIS https://en.wikipedia.org/wiki/DOCSIS
- voxadam 3y agoI'm almost certain that modern ADSL variants employ up to at least 32768-QAM.
- dfox 3y agoModern ADSL and VDSL version typically use DMT, which is more or less the same thing as OFDM. Interesting part of that in context of xDSL is that each of the subcarriers (typically QAM-64 modulated) can have different amount of actual payload data assigned to them depending on the loop quality and interference (many xDSL CPEs have spectrogram somewhere in their web interface which directly shows how the payload is distributed over the subcarriers).