Quadrature Amplitude Modulation Symbol Mapping Method for Cable Modem

摘要

The present invention relates to a cable modem, and in order to reduce the size of hardware and the simplicity of design by mapping symbols using 64 QAM constellations in common by one 256 QAM constellation in symbol mapping. It is an object of the present invention to provide a method for mapping a quadrature amplitude modulation symbol of a cable modem.;For this purpose, a total of 64 bundles of four 8-bit symbols corresponding to 256 QAM constellation coordinates are used as a bundle, and one of the 8-bit symbols in each bundle is represented as a representative symbol of each bundle. Next, if 8-bit data is input, symbol mapping is performed by the 256 QAM constellation. If 6-bit data is input, 64 QAM symbol mapping is performed by ignoring 2 bits of the 8-bit representative symbols. Is accomplished by