The Boeing Company

Kristin Farag

Susan E Bach

Methods and apparatus for use in making improved symbol decisions in a demodulator in the presence of distortion in the received signaling. In one implementation, a method includes the steps of: determining a centroid symbol location for a received symbol of a constellation, the centroid symbol location different than an ideal symbol location due to distortion of the received symbol; and adjusting a decision line bounding the received symbol based on the centroid symbol location. In preferred embodiments, the method is implemented in a satellite communication system, which the distortion is a nonlinear distortion and is caused by a high power amplifier at the transmitting terminal and in which bandwidth efficient modulation formats are used to transmit data at a high rate. In some embodiments, centroid symbol locations are used to improve soft decision decoding.

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San Dimas, CA, United States of America

Kristin Farag