CMTS Edge Series Universal Quick Start Guide
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Section 8
–
OFDM Channel Setup
The CMTS Edge 32 Plus and the CMTS Edge MAX support an additional OFDM downstream channel that
can be used by DOCSIS 3.1 cable modems. The CMTS Edge 32 Plus supports one (1) OFDM channel,
while the CMTS Edge MAX supports up to five (5) full-spectrum (192Mhz) OFDM channels. Follow these
steps to enable them.
To enable OFDM channels, click on the
OFDM Channel
under the
RF Configuration section
of the left
menu.
1.
Do not OPEN (activate) the OFDM channel until all changes have been made and saved.
2.
Subcarrier Spacing
can be either 25 or 50 kHz (50 is the default).
3.
Subcarrier Zero Frequency
should be 6.4 MHz below the
Start Spectrum
.
4.
Start Spectrum
is the beginning edge of the OFDM channel spectrum . Do not overlap any
Downstream channels other active carriers on the RF cable system.
5.
End Spectrum
defines the upper edge of the OFDM channel spectrum. OFDM channels can be
24-192 MHz wide.
6.
PLC Frequency
is the Physical Link Channel - a 6-MHz wide carrier within the OFDM channel that
carries information to the CM about the OFDM channel. This is what the CM first locks on to and
must be within the OFDM channel spectrum.
7.
Once all settings have been made,
Submit
the changes to the
Running Configuration
, and
Save
Config
to the
Startup Configuration.
8.
Select
the channel(s) you just modified, and click the
Open OFDM Channel
to activate the
channel(s). The status will change from a yellow “X” to a green Check Mark.
Figure 15 is an example of (2) OFDM channels (194 and 195) whose spectrum is configured above 32
active DOCSIS 3.0 downstream channels on a CMTS (D3.0 channel information not shown here). The
diplexer in use is a 204/258 MHz diplexer.
These settings should enable DOCSIS 3.1 modems to register. Additional settings for OFDM channels
are further explained in the Command Reference Guide Manual. Above settings shown for testing
purposes with a 204/258 MHz diplexer.
Section 9
–
OFDMA Channel Setup
The CMTS Edge MAX allows the use of both ATDMA DOCSIS 3.0 upstream channels and up to two
(2) OFDMA DOCSIS 3.1 upstream channels simultaneously, provided the cable modem is able to
operate in “mixed
-
mode”.
Figure 15
–
OFDM Channel Setup
