via the ab channel along signal path 510 and the ac channel along signal path 512 therefore in fig1 a a plot 1000 of carrier frequency signals of various bit loading constellations 1002 versus carrier number 1004 for the ab channel path between node a and node b is shown line 1006 represents the ab channel and follows an envelope of the constellation sizes of the 8 different carrier number signals within the ab channel as an example within the ab channel carrier number signals 1 and 8 may transmit at a constellation size of 256 qam carrier number signals 2 3 and 7 may transmit at a constellation size of 128 qam carrier number signals 4 and 6 may transmit at a constellation size of 64 qam and carrier number signal 5 may be off i e no carrier signal of any constellation size may be transmitted because of the null in the channel characteristics similarly in fig1 b a plot 1008 of carrier frequency signals of various bit loading constellations 1010 versus carrier number 1012 for the ac channel path between node a and node c is shown line 1014 represents the ac channel and follows an envelope of the constellation sizes of the 8 different carrier number signals within the ac channel as an example within the ac channel carrier number signals 1 2 4 6 and 8 may transmit at.