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.
Claims19
A digital, communication system, comprising:
- a transmitter configured to transmit signals to a receiver via a communication channel;
- wherein the transmitter, comprises:
- a coder configured to receive user bits and output encoded bits at an expanded output encoded bit rate;
- a mapper configured to map said encoded bits to symbols in a symbol, constellation;
- a modulator configured to generate a signal, for transmission via the communication channel, using symbols generated by the mapper;
- wherein the receiver, comprises:
- a demodulator configured to demodulate the received signal, via the communication channel;
- a demapper configured to estimate likelihoods from the demodulated signal;
- a decoder that is configured to estimate decoded bits from the likelihoods generated by the demapper;
- and
- wherein the points of the symbol, constellation have non-uniform inter-point distances selected to achieve a gain in capacity for a predetermined signal, to noise ratio (SNR) relative to a symbol, constellation having uniform inter-point distances.
Dependencies are inferred from the claim text.