TCM SCHEMES WITH PARTIALLY OVERLAPPED SIGNAL CONSTELLATIONS

In conventional TCM schemes, for a rate of n bits per channel symbol, a 2n+1-point constellation is used. In this work, we show that using c onstellations with less than 2n+1-points, one can achieve a considerab le coding gain in comparison to the traditional 2n+1-point constellati on. The increase in coding gain is due to a reduction in transmitted s ignal energy as a result of deleting some high power signals from the original 2n+1-point constellation and reuse of some of the low power s ignals instead.