US Patent 7684756 Adaptive subcarrier loading

A wireless multicarrier transmission method wherein subcarriers of the transmission are adaptively modulated. The fading condition of each subcarrier is detected to generate fading channel profile information. Adaptive loading tables are calculated for lower, standard, and higher modulation schemes. One of the adaptive loading tables is selected and those subcarriers having low fading channel profile information are modulated with the lower modulation scheme, subcarriers having medium fading channel profile information are modulated with the standard modulation scheme, and subcarriers having high fading channel profile information are modulated with the higher modulation scheme.