Patent ID: 7515642

Claim:
A communication device that is operable to generate an LDPC (Low Density Parity Check) coded signal, the communication device comprising: an LDPC encoder that encodes a plurality of information bits using a generator matrix G, that has a corresponding parity check matrix H, thereby generating a plurality of 7 bit symbol labels comprising 3 uncoded bits and 4 coded bits; and a symbol mapper that maps the plurality of 7 bit symbol labels according to a 128 DSQ (Double Square Quadrature amplitude modulation) constellation comprising 128 constellation points into modulation symbols, wherein: the 128 DSQ constellation consists of 2 separate 64 QAM (Quadrature Amplitude Modulation) constellations, offset with respect to each other, whose 128 constellation points are divided into 8 regions such that each region comprises 16 constellation points therein; the 3 uncoded bits indicate to which of the 8 regions a 7 bit symbol label corresponds; and the 4 coded bits indicate to which of the 16 constellation points within a region the 7 bit symbol label corresponds.