Editing DOCSIS (section)

===Physical layer===
* Channel width:
** Downstream: All versions of DOCSIS earlier than 3.1 use either 6&nbsp;MHz channels (e.g. North America) or 8&nbsp;MHz channels ("EuroDOCSIS"). DOCSIS 3.1 uses channel bandwidths of up to 192&nbsp;MHz in the downstream.<ref>{{cite web |title=DOCSIS Technology |url=https://www.rohde-schwarz.com/pl/technologies/cable_tv/docsis/docsis-technology/docsis_technology_55513.html |website=Rohde & Schwarz}}</ref>
** Upstream: DOCSIS 1.0/1.1 specifies channel widths between 200&nbsp;kHz and 3.2&nbsp;MHz. DOCSIS 2.0 & 3.0 specify 6.4&nbsp;MHz, but can use the earlier, narrower channel widths for backward compatibility. DOCSIS 3.1 uses channel bandwidths of up to 96&nbsp;MHz in the upstream.
* Modulation:
** Downstream: All versions of DOCSIS prior to 3.1 specify that 64-level or 256-level [[Quadrature amplitude modulation|QAM]] (64-QAM or 256-QAM) be used for modulation of downstream data, using the [[ITU-T]] J.83-Annex B standard<ref>{{cite web |url=http://www.itu.int/rec/T-REC-J.83-200611-S!Amd1/en |title=Recommendation J.83 (1997) Amendment 1 (11/06) |date=November 2006 |access-date=June 20, 2013 }}</ref> for 6&nbsp;MHz channel operation, and the DVB-C modulation standard for 8&nbsp;MHz (EuroDOCSIS) operation. 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.
** Upstream: Upstream data uses [[Phase-shift keying#Quadrature phase-shift keying (QPSK)|QPSK]] or 16-level QAM (16-QAM) for DOCSIS 1.x, while QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM are used for DOCSIS 2.0 and 3.0. DOCSIS 2.0 and 3.0 also support 128-QAM with [[Trellis modulation|trellis coded modulation]] in [[SCDMA|S-CDMA]] mode (with an effective [[spectral efficiency]] equivalent to that of 64-QAM). DOCSIS 3.1 supports data modulations from QPSK up to 1024-QAM, with optional support for 2048-QAM and 4096-QAM.