Predistortion of signal constellation? I am trying to learn aspects of space/satellite communications. So Amplitude-Phase Shift Keying is quite popular in this domain.

APSK over Non Linear channels has worse performance than the earlier used PSK. Which is important because to non linear effects caused by the power amplifier on board. To counteract the effects of non linear distortion, one of the techniques used is Pre Compensation at the modulator.

This involves constellation predistortion. What does this mean? 

Does this refer to error control encoding schemes like convolutional coding, tcm, turbo coding etc?
In very general terms, pre-distortion means altering a signal's shape, so that after it goes through the channel, the output looks like the original signal. So you basically alter the signal by the inverse of the distortion.

This is a separate issue from coding.