Real-time adaptive power control in satellite communications systems

Apparatus for providing adaptive power control in communications systems wherein first and second stations communicate serial streams of binary data bits via a power-limited repeater having a power output which is functionally related to power input, comprising:

• quality monitor means associated with said second station for providing an indication of the quality of the signal received by said second station from said first station via said power-limited repeater;
• encoding means for encoding said signal quality indication onto a first serial stream of binary data bits transmitted to said first station from said second station, and including means responsive to said signal quality indication for providing a second serial stream of binary data bits in accordance therewith and having a bit rate equal to X/Nth that of said first serial stream of binary data bits, where X and N are integers and means responsive to said first and second serial streams of binary data bits for providing an output bit stream having a bit rate (N+X)/N times the bit rate of said first serial stream of binary data bits, wherein N/(N+X) of the bits of said output bit stream correspond to the bits of said first serial stream of binary data bits, and X/(N+X) of the bits of said output bit stream correspond to the bits of said second serial stream of binary data bits, said output bit stream being provided for transmission to said first station in place of said first serial stream of binary data bits;
• decoding means associated with said first station, responsive to said output bit stream received from said second station, for extracting said signal quality indication therefrom and including means responsive to said output bit stream for separating said first and second serial streams of binary data therefrom;
• and
• means at said first station for adjusting the power level of said signal transmitted by said first station to said second station via said repeater, in accordance with said signal quality indication as recovered by said decoding means,
• whereby said signal quality indications are communicated between said stations without requiring a separate communications channel.