1. technology and computing
2. hardware
3. computer networking
4. router

SCPC Return and Multi-Channel Demod Configuration Brief
iDX 3.1 software is the latest upgrade to iDirect’s Evolution platform. iDX 3.0 and iDX 3.1 bring significant new
features and benefits to users.
The most innovative feature is SCPC Return capability enabling users to operate Evolution® routers in DVB-S2/
ACM outbound and in either TDMA or SCPC Return mode. With this new switching capability in iDX 3.0,
users gain the flexibility to adjust service levels to dynamic applications and changing traffic patterns, while
maintaining an economical way to utilize total network capacity and optimize operational efficiencies.
Another important feature of iDX 3.0 is adding a Multi-Channel Demod capability to Evolution® line cards. An
Evolution XLC-M or eM0DM line card can now support 4 or 8 return channels with the appropriate software
license key. In iDX 3.1 a license for 16 narrowband return channels is also available for the XLC-M. This multichannel demod capability of operating multiple return channels on the same line card allows users to take
advantage of efficiencies in their hub infrastructure of up to 40% due to fewer line cards and chassis space
needed. The following configuration details are important when designing your multi-channel SCPC or TDMA
network:
Line cards and Remotes
• Most Evolution line cards (XLC-M, eM1D1 and eM0DM) support SCPC-Return
• All Evolution remotes (X3, X5, e8350, e800 and e850mp) support TDMA and SCPC Return. The Evolution X1
remote only supports TDMA
Multi-channel Licenses
• No license is required to operate the XLC-M/eM0DM as a single TDMA or SCPC Return demodulator (the eM1D1
can only operate in single channel TDMA or SCPC Return)
• With appropriate licenses new or existing XLC-M/eM0DM line cards under iDX 3.0 can be configured to operate
up to 4 or 8 TDMA demodulators or up to 8 SCPC Return demodulators. In iDX 3.1 the XLC-M can also be
configured to operate 16 TDMA demodulators.
• Each XLC-M/eM0DM line card can receive up to the licensed number of channels within 36MHz of spectrum
(+/-18MHz from chosen center frequency)
• SCPC Return allows independence of symbol rates, modulation, FEC coding and block size across all channels
on the line card. For TDMA, the symbol rate, modulation, and block sizes of all channels must be identical
Maximum Carrier Sizes
In TDMA mode
• The line card supports an aggregate symbol rate of up to 7.5Msps depending on the inroute modulation,
coding and code block size chosen
• The multichannel TDMA image has a maximum symbol rate of 5.875Msps for any single channel
• The 16 TDMA channel license limits each return channel to 128 ksps
• Uses iDirect’s unique and highly efficient inbound FEC coding scheme 2D 16-State, TPC is not supported
• When on different inroute groups each carrier can be independently configured in terms of symbol rate,
modulation, FEC rate and block size, thus each link can be optimized to link budget and data rate requirements
SCPC Return and Multi-Channel Demod Configurations
In SCPC mode
• The line card supports a maximum symbol rate of 11.75Msps for any single channel (XLC-M and eM0DM), and
a maximum of 15 Msps (eM1D1)
• The max aggregate carrier combination on a line card cannot exceed 40Mbps
• SCPC Return demodulator speeds can exceed the maximum throughput of some remotes, therefore the
stated speeds for the demodulator may not be achieved on a per remote basis
TDMA Inroute Groups
• An XLC-M can be configured with eight homogeneous TDMA channels supporting an inroute group with
multiple remotes. ‘Homogeneous TDMA channels’ means that each TDMA channel on an XLC-M/eM0DM
must be configured with the same symbol rate and same FEC and block size coding
• Multiple TDMA channels can be associated with the same line card
• One inroute group is supported per XLC-M/eM0DM line card. All channels on a single XLC-M line card must
belong to the same inroute group
• The symbol rate, MODCOD, and block sizes of TDMA channels need to be assigned to the same inroute group
and thus be identical
Redundancy
• An unlicensed XLC-M can function as a single channel demod of either TDMA or SCPC Return and for
redundancy may be backed up by any XLC-M whether licensed or not
• A XLC-M licensed for more than one demodulator on a given type (TDMA or SCPC Return) may only be
backed up by another licensed for equal or more multichannel demods of the same type
• The XLC-M licensed with 16 narrowband return channels can only be backed up by another 16 channel
licensed XLC-M card
Network Management
The entire network is managed by iDirect’s NMS, iVantage®. The process of moving routers between TDMA
and SCPC Return is done via the NMS configuration tool, iBuilder. In support of the SCPC Return feature and
multi-channel capability of the line card, iBuilder is optimized in iDX 3.0 to allow for easier and more dynamic
management of multiple inroutes whether in SCPC or TDMA mode.
If you need assistance with designing your network or want to learn more about iDX 3.0 and iDX
3.1capabilities, please contact your iGT Sales Representative.
iDirect Government Technologies
13921 Park Center Road
Suite 600
Herndon, VA 20171
703.648.8118
www.iDirectGT.com
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