Newtec MDM6000 - Flexacm

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Feature Descriptions MDM6000 Satellite Modem
14.7 FlexACM
In a satellite link operated with FlexACM, the modulator and demodulator parts must exchange
signaling information with each other in order to control dynamically the modulation parameters in
function of the instantaneous receive conditions in the demodulator. This signaling consists of short
messages in IP format. The average bit rate of this communication is very low (only a few hundred
bits per second).
The ACM forward signaling is transmitted over the satellite link (RF). The return signaling can be
transmitted over any communication channel between the modulator and demodulator, being a
satellite link or a terrestrial link.
Since there is by definition always a satellite link between the modulator and demodulator, the
communication from the modulator to the demodulator is in most cases transmitted in the satellite
signal itself. It is possible to send this signaling message in the same stream as the IP payload, or to
isolate it from the payload in another DVB-S2 or S2-Extesnions stream (multi stream configuration).
For the FlexACM communication between the demodulator and the modulator, the implementation
depends on the topology of the network. For two-way DVB-S2 transmissions, the FlexACM
signaling can be transmitted in the DVB-S2 or S2-Extension return link, mixed with the IP payload or
in a separate DVB-S2 or S2-Extension stream. The FlexACM signaling can also be transmitted in
any other type of satellite return channel (for example VSAT) or terrestrial link (ADSL, GPRS,
etc…).
Enable ACM in the Encapsulator. Refer to the following sections:
• BBFEncapsulationChannelsonpage232
• TSEncapsulationPIDsonpage241