Premier Mounts CDM-600 specifications Automatic Uplink Power Control, Introduction

Chapter 12. AUTOMATIC UPLINK POWER CONTROL

12.1Introduction

Automatic Uplink Power Control (AUPC) is a feature whereby a local modem is permitted to adjust its own output power level in order to attempt to maintain the Eb/No at the remote modem.

WARNING

The user MUST obtain permission from the Satellite Operator to use this feature.

Improper use of this feature could result in a transmitting terminal seriously exceeding its allocated flux density on the Operator’s satellite. This could produce interference to other carriers, and could cause transponder saturation problems

To accomplish this, either the EDMAC or D&I++ framing types may be used. The remote modem constantly sends back information about the demodulator Eb/No using reserved bytes in the overhead structure. The local modem then compares this value of Eb/No with a pre-defined target value. If the Remote Eb/No is below the target, the local modem will increase its output power, creating a closed-loop feedback system over the satellite link. A particularly attractive benefit of this feature is that whenever framed operation is selected, the remote demodulator’s Eb/No can be viewed from the front panel display of the local modem. Note that both EDMAC and AUPC can be used simultaneously with either framing type.

There are several important parameters associated with this mode of operation, and the user needs to understand how the AUPC feature works, and the implications of setting these parameters.

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