Methods and apparatuses for signaling with geometric constellations
AssigneeConstellation Designs, LLC
InventorsMaged F. Barsoum, Christopher R. Jones
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Abstract
Communication systems are described that use signal constellations, which have unequally spaced (i.e. ‘geometrically’ shaped) points. In many embodiments, the communication systems use specific geometric constellations that are capacity optimized at a specific SNR. In addition, ranges within which the constellation points of a capacity optimized constellation can be perturbed and are still likely to achieve a given percentage of the optimal capacity increase compared to a constellation that maximizes dmin, are also described. Capacity measures that are used in the selection of the location of constellation points include, but are not limited to, parallel decode (PD) capacity and joint capacity.
Claims23
A method of receiving data, comprising:
- receiving a signal at a receiver via a communication channel having a channel signal-to-noise ratio (SNR), where the receiver comprises a demodulator, a demapper, and a decoder;
- demodulating the received signal into a demodulated signal using the demodulator and providing the demodulated signal to the demapper via a coupling between the demodulator and the demapper;
- determining likelihoods using the demapper based upon the demodulated signal and a non-uniform quadrature amplitude modulation 1024-point symbol constellation (NU-QAM 1024);
- providing the determined likelihoods to the decoder via a coupling between the demapper and the decoder;
- and
- providing a sequence of received bits from the decoder based upon the determined likelihoods and a low density parity check (LDPC) code;
- wherein the NU-QAM 1024 constellation comprises an in-phase component and a quadrature component, where each component comprises 32 levels of amplitude such that the amplitudes scaled by a scaling factor are within 0.15 from the following set of amplitudes:
- −34.448, −30.817, −27.660, −24.807, −22.185, −19.751, −17.476, −15.333, −13.305, −11.366, −9.509, −7.701, −5.953, −4.220, −2.533, −0.834, 0.833, 2.533, 4.220, 5.953, 7.701, 9.509, 11.366, 13.305, 15.333, 17.476, 19.752, 22.186, 24.808, 27.660, 30.818, and 34.449.
Dependencies are inferred from the claim text.