Q-Flex Satellite Modem Installation and Operating Handbook
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7.9 DVB-S2 and SmartLink
The
Q-Flex™
modem supports SCPC, DVB-S2 and combined SCPC/DVB-S2 operation.
The DVB-S2 standard was approved by ETSI (European Telecommunications Standards
Institute) in November of 2006. The new standard incorporates the latest technology in
order to provide greater spectral efficiency and improved stability, using high-order
modulation schemes and more powerful FEC coding.
It is a common misconception that DVB-S2 is a standard for the broadcast of video but
this is incorrect as the standard is essentially data agnostic. DVB-S2 allows for
both
continuous data streams (such as those provided by G.703, HSSI and EIA530 interfaces)
and packetised data (such as IP and MPEG video). The space segment savings of DVB-
S2 can therefore be obtained equally on a wide range of satellite links ranging from
traditional low-rate SCPC links to high rate broadcast video and IP. Initial DVB-S2
satellite modem products in the industry reflected the high pioneering costs of the
technology and were aimed at high-end broadcast video and IP markets. Teledyne
Paradise Datacom is proud to bring this technology to a much wider market in the form of
the cost-competitive
Q-Flex™
modem, which provides backwards compatibility for legacy
SCPC links and a painless migration path to newer bandwidth-saving technology.
The
Q-Flex™
allows:
•
DVB-S2 outbound with an SCPC return or an SCPC outbound with a DVB-S2
return.
•
DVB-S2 outbound and return.
•
SCPC outbound and return.
•
SmartLink
mode where SCPC features are combined with DVB-S2 space
segment savings. All traditional SCPC features such as IBS, IDR, Drop and Insert,
ESC, AUPC, etc. are supported.
DVB-S2 does not directly support any of these SCPC features and therefore
SmartLink
was developed to allow existing SCPC services to benefit immediately by switching to the
newer highly-efficient DVB-S2 technology without compromising the services being
provided.
SCPC, DVB-S2 and
SmartLink
processing paths through the modem are shown in the
diagram
overleaf.
The
top
path
(Interface-Framer-Outer
FEC-Inner
FEC-
Modulator/Demodulator) shows the path used in SCPC processing and the functionality
that is associated with each of these blocks. The lower path (Interface-SCPC Framer-
DVB-S2 Framer-Outer FEC-Inner FEC-Modulator/Demodulator) shows the path used in
DVB-S2 and
SmartLink
processing. Note that ‘pure’ DVB-S2 bypasses the SCPC framer
and uses the DVB-S2 framer only.
SmartLink
takes the output of the SCPC framer (which
includes the output from Drop and Insert, the ESC channel, etc.) and overlays this with
DVB-S2 framing. Even although this can involve two lots of framing (depending on
whether SCPC Closed Network mode is selected) the increased overhead is more than
offset by the savings of switching to DVB-S2 space segment.
Figure 7-14
shows which features can be mixed in
SmartLink
mode and which cannot –
for example, 16QAM appears on the SCPC processing path only and is therefore not
available when
SmartLink
is operational.
