SHAPING THE FUTURE OF SATELLITE COMMUNICATIONS
9.2 The Noise and Distortion Estimator (NoDE)
9.2.1 Introduction
NoDE (Noise & Distortion Estimator) simplifies ground station operation activities
and enables an efficient usage of transponders. NoDE is a unique and innovative
tool that simplifies ground station operation activities by providing a means to
monitor the quality of the satellite link. It performs a continuous and accurate
measurement of the noise margin and the amount of non-linear distortion on the
received satellite signal. NoDE allows operators to easily fine tune their satellite
links to their optimal operational point under any circumstances. Regular fine
tuning of the satellite link parameters will increase the efficiency of the transponder
and at the same time provide financial benefits.
In addition, NoDE enables the operator to view the linear and non-linear effects
from changes in the uplink power. It can help to prevent errors in operations such
as the addition of too much power and distortion that could lead to the total loss of
the communication links.
NoDE is the perfect tool to provide operators full control over transmission
performance when linear and non-linear distortions are present. It enables higher
modulation schemes such as 16APSK and 32 APSK and helps operators to get the
most out of their transponder.
9.2.2 How Does NoDE work
In digital satellite communications the energy per symbol related to the noise
power spectral density (Es/No) is an important parameter used to determine the
quality of the transmission. The Es/No measurement at the receiver side needs a
certain threshold to ensure an error-free transmission.
Figure 87 - PER Vs Es/No
It is commonly accepted that a transmission is considered as error-free when the
PER (Packet Error Rate) at the reception side is below 10
-7
. For each DVB-S2
ModCod, as shown in Figure 87, a minimum value (Es/No)
QEF
guarantees quasi
error free transmission.
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