Uplink Power Control
Pronunciation: U-P-C
Also written as: UPC — Uplink Power Control
An automatic system that increases the earth station's transmit power during propagation fade events to maintain a stable received signal level at the satellite.
Full Definition
Uplink Power Control (UPC), also called Automatic Uplink Power Control (AUPC), is a closed-loop or open-loop technique used at ground stations to counteract the effects of rain fade and other propagation impairments on the uplink. In closed-loop UPC, the satellite or a reference station measures the received Eb/No or carrier level and feeds back a correction signal to the transmitting earth station, which then adjusts its HPA output. UPC range is typically 0 to 10 dB above the nominal clear-sky power level. Editors must distinguish UPC from downlink fade compensation, which may use ACM or site diversity at the receive end rather than increased transmit power.
Usage
Usage note: Expand 'UPC' as 'Uplink Power Control' on first use. Distinguish from AUPC (which implies a closed-loop feedback mechanism) if the document requires that level of precision.
In Context
- "The ground station's UPC range of 6 dB provides sufficient headroom to maintain link availability during moderate rain events." — System design report
- "AUPC was enabled and the transmit power ramped up by 4.5 dB during the convective rain event." — Operations log