Appendix C Dynamic Power Control; Introduction - Comtech EF Data Vipersat 564L User Manual

D
YNAMIC

Introduction

Dynamic Power Control (DPC) provides a mechanism whereby VIPERSAT
satellite links have their transmit power levels adjusted in order to optimize the
receive signal quality (as measured by the demodulator E
tion process acts to either increase or decrease transmitted signal levels in order
to:
DPC can be selectively enabled and disabled on a link-by-link basis and works
on both point-to-point as well as point-to-multipoint links. DPC relies on the
passing of an IP message between the receive site (where the receive quality is
being measured) and the transmit site (where the power level is to be adjusted).
These DPC packets are IP unicast messages, and only the transmit site whose
frequency and Network ID number matches that contained in the IP message
will act on the message.
The Vipersat CDM (modulator) units have an algorithm that, when activated,
automatically adjusts the modulator transmit power to maintain a constant
nominal receive signal quality (E
This provides a mechanism to compensate for varying signal levels caused, for
example, by the use of different antenna sizes in a mesh network, or if Ku band
is being used as a means to compensate for rain fade conditions. The power
A p p e n d i x D y n a m i c P o w e r C o n t r o l
C -
P
OWER
• Achieve a minimum level of received E
error free link.
• Reduce transmit power where sufficient link margin exists in order to
optimize station uplink and satellite transponder power usage.
C
ONTROL
/N ) at the corresponding receive station(s).
b o
A
P P E N D I X
/N ). This optimiza-
b o
/N consistent with providing an
b o
C-1