Study on non-linear compensation technique based on signal point error estimation over satellite transponder

We are studying 16APSK and 32APSK, which can transmit more HDTV programs per channel or be applied for high quality services beyond HDTV. Multi-level modulations such as these APSK schemes are vulnerable to the non-linear distortion of a satellite transponder. We propose a compensation technique for estimating the signal point error vectors over a satellite simulator in advance and compensating for the error vectors of each signal point at the transmitter. We report on both 16APSK and 32APSK performances in terms of the required C/N and optimum operating point of the traveling wave tube amplifier (TWTA) by using a computer simulation on the effect of this compensation technique.