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

Claim 0:
1. A communication system, comprising:
a sink device capable of receiving data bits;
a receiver capable of receiving 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 capable of demodulating a received signal into a demodulated signal;
a demapper, coupled to the demodulator, capable of determining 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; and

a decoder, coupled to the demapper, capable of using 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 use of the unequally spaced QAM-64 symbol constellation in combination with any LDPC code from the set of LDPC codes provides a greater SNR gain than is obtained when utilizing the uniformly spaced QAM-64 symbol constellation in combination with that particular LDPC code; 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.