Patent ID: 11864007
Assignee: CONSTELLATION DESIGNS, LLC
Field: Digital communication (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 23:
24. A communication system, comprising:
a sink device capable of receiving data bits;
a receiver that receives signals via a communication channel having a channel signal-to-noise ratio (SNR) and providing data bits to the sink device, wherein the receiver comprises:
a demodulator that demodulates a received signal into a demodulated signal;
a demapper that determines likelihoods using the demodulated signal and a symbol constellation selected from a set of symbol constellations comprising:
an unequally spaced Quadrature Amplitude Modulated 64 point (QAM-64) symbol constellation; and
a uniformly spaced QAM-64 signal constellation that maximizes the minimum distance, dmin, between the constellation points; and

a decoder that uses the likelihoods determined by the demapper to provide a sequence of received bits based upon a low density parity check (LDPC) code selected from a set of LDPC codes having different code rates;

wherein the demapper is interposed between the demodulator and the decoder, and the demapper receives information from the demodulator and provides information to the decoder; and
wherein use of a specific LDPC code having a code rate that is greater than 1/2 from the set of LDPC codes in combination with the unequally spaced QAM-64 symbol constellation provides a larger SNR gain than the SNR gains achieved using the unequally spaced QAM-64 symbol constellation in combination with any of the other LDPC codes from the set of LDPC codes.