The influence of the selection of constellations set on the bit/power carrier loading in DMT modulation is analyzed. Two constellations sets are used: rectangular (non- optimum) and square/cross/triangle (closer to optimum) as well as a variant of Hughes-Hartogs bit/power loading algorithm.

The constellation set selection only slightly affects total throughput but the variations of transmitted subcarrier powers are much higher for (non-optimum) rectangular constellations.