SHAPING THE FUTURE OF SATELLITE COMMUNICATIONS
Figure 88 - LME – Linear Environment
In a linear environment, as described in Figure 88, the Link Margin Estimates
(LME) provided with or without NoDE is identical. They correspond with the
difference between the channels Es/No and the (Es/No)
QEF
of the corresponding
ModCod, which is the real operation margin of the transmission.
Figure 89 :LME – Non-Linear Environment
When non-linear distortion is present, the real link margin is decreased and is no
longer equal to the difference between the measured Es/No value and (Es/No)
QEF
.
NoDE calculates the amount of distortion present on the received signal, then
corrects the minimum ES/No value to obtain quasi error-free transmission by a delta
Δ that takes into account the effect of the distortion. In a non-linear environment, as
described in Figure 89, NoDE enables the measurement of an accurate Link
Margin Estimation. By providing the operator with an accurate estimation of the
Real Link Margin, NoDE prevents the link being operated in a region where the
performance is unpredictable and only marginally stable.
By observing the evolution of (Es/No)
QEF
+ Δ functioning in a variation of the uplink
power, NoDE can also help the operator to find the optimal operational point of the
transponder without interrupting the transmission.
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