Newtec MDM6000 - Dummy PL Scrambler Mode; Physical Layer Scrambler Signature; Roll off Signaling

Newtec Proprietary
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Feature Descriptions MDM6000 Satellite Modem
14.1.17.2.1 Dummy PL Scrambler Mode
MDM6000 >> Modulator >> Modulation >> Dummy PL scrambler mode
When bursty traffic (like IP) is transported, the physical layer can run out of data to transmit. In that
case dummy physical layer frames are transmitted in order to keep the receiver locked.
There are two possible modes to perform scrambling of the dummy physical layer frames.
• DVB-S2 and DVB-S2X Standardized Reset (reinitialized):
In this mode the randomization sequence is reinitialized at the end of each dummy physical layer
frame header.
• Continuous:
In this mode there is no re-initialization at the end of each dummy physical layer frame header.
This is done to achieve more randomness in the dummy physical layer frames (carrier data) as
desirable for bandwidth cancellation. The bandwidth canceller needs randomization in order to
measure the time delay between the transmitted and the returned signal.
This Continuous mode is only valid for the dummy physical layer frames!
The Continuous mode is not DVB compliant.
As a consequence it is possible that some non-Newtec demodulators are not capable
of working with this mode.
14.1.17.2.2 Physical Layer Scrambler Signature
MDM6000 >> Modulator >> PL Scrambler Signature
The following information about the Physical Scrambler Signature is taken from the
DVB-S2 standard. Refer to the following document, ETSI EN 302 307.
In case of broadcasting services, the PL Scrambler Signature = 0 shall be used as default sequence,
this to avoid manual receiver setting or synchronization delays.
The PL Scrambler Signature, assuming values in the range 0 to 262 141, indicates the spreading
sequence number. The use of different PL Scrambling sequences allows a reduction of interference
correlation between different services. For the same purpose, it is possible to reuse a shifted version
of the same sequence in different satellite beams. Furthermore, the PL Scrambler Signature can be
unequivocally associated to each satellite operator, satellite, or transponder, thus permitting
identification of an interfering signal via the PL Scrambling "signature" detection. There is no explicit
signaling method to convey the PL Scrambling signature value to the receiver.
14.1.17.2.3 Roll Off Signaling
MDM6000 >> Modulator >> Roll Off Signaling