Constellation map optimization for highly spectrally efficient communications
A method and system for optimizing symbol mapping in partial response based communications that are based on use of pulse-shaping that incorporates a predetermined amount of inter-symbol interference (ISI). Optimizing symbol mapping symbol mapping may comprise configuring optimized constellation mapping for use in mapping and/or de-mapping data communicated using the partial response pulse-shaping. In this regard, the optimized constellation mapping may be based on a reference constellation mapping that is utilized for reference modulation scheme, and the configuring comprises applying adjustments to one or more constellation points in the reference constellation mapping. The optimized constellation mapping may be configured to optimize an applicable minimum distance for one or more selected error patterns for a given spectral compression applied during partial response based communications. The configuring of the optimized constellation mapping may be based on feedback information provided during communication of data.
1. A system comprising:
circuitry of a transmitter, said circuitry being operable to:
receive a bitstream to be transmitted;
map, using a symbol constellation, each of a plurality of groups of one or more bits of said bitstream to a corresponding one of a plurality of symbols;
transmit said plurality of symbols; and
adjust, during said mapping of said plurality of groups of one or more bits of said bitstream, a configuration of said symbol constellation based on one or more error patterns determined to be associated with one or more of said plurality of symbols.
2. The system of claim 1 , wherein said adjustment of said configuration of said symbol constellation is such that a first configuration of said symbol constellation is used for a first one of said plurality of groups of one or more bits of said bitstream and a second configuration of said symbol constellation is used for a second one of said plurality of groups of one or more bits of said bitstream.
3. The system of claim 1 , wherein said adjustment of said configuration of said symbol constellation is based on a minimum distance of said one or more error patterns.
4. The system of claim 3 , wherein said adjustment of said configuration of said symbol constellation attempts to increase said minimum distance.
5. The system of claim 1 , wherein:
a first subset of the points of said symbol constellation are the same for a first configuration of said symbol constellation and a second configuration of said symbol constellation; and
a second subset of the points of said symbol constellation are different for said first configuration of said symbol constellation and said second configuration of said symbol constellation.
6. The system of claim 1 wherein:
for a first configuration of said symbol constellation, the points of said symbol constellation are regularly spaced;
for a second configuration of said symbol constellation, the points of said constellation are irregularly spaced.
7. The system of claim 1 , wherein said adjustment of said configuration of said symbol constellation is based on feedback from a receiver of said plurality of symbols.
8. The system of claim 7 , wherein said feedback comprises a performance indicator associated with said plurality of symbols.
9. The system of claim 1 , wherein:
said one or more error patterns are the N most-frequently occurring error patterns for said system; and
N is a positive integer.
10. The system of claim 1 , wherein:
said circuitry of said transmitter comprises a pulse shaping filter; and
said circuitry is operable to adjust a response of said pulse shaping filter in conjunction with said adjustment of said configuration of said symbol constellation.
11. A method comprising:
performing in circuitry of a transmitter:
receiving a bitstream to be transmitted;
mapping, using a symbol constellation, each of a plurality of groups of one or more bits of said bitstream to a corresponding one of a plurality of symbols;
transmitting said plurality of symbols; and
adjusting, during said mapping of said plurality of groups of one or more bits of said bitstream, a configuration of said symbol constellation based on one or more error patterns determined to be associated with one or more of said plurality of symbols.
12. The method of claim 11 , wherein said adjusting of said configuration of said symbol constellation is such that a first configuration of said symbol constellation is used for a first one of said plurality of groups of one or more bits of said bitstream and a second configuration of said symbol constellation is used for a second one of said plurality of groups of one or more bits of said bitstream.
13. The method of claim 11 , comprising performing said adjusting of said configuration of said symbol constellation based on a minimum distance of said one or more error patterns.
14. The method of claim 13 , wherein said performing said adjusting of said configuration of said symbol constellation attempts to increase said minimum distance.
15. The method of claim 11 , wherein:
a first subset of the points of said symbol constellation are the same for a first configuration of said symbol constellation and a second configuration of said symbol constellation; and
a second subset of the points of said symbol constellation are different for said first configuration of said symbol constellation and said second configuration of said symbol constellation.
16. The method of claim 11 wherein:
for a first configuration of said symbol constellation, the points of said symbol constellation are regularly spaced;
for a second configuration of said symbol constellation, the points of said constellation are irregularly spaced.
17. The method of claim 11 , comprising performing said adjusting of said configuration of said symbol constellation based on feedback from a receiver of said plurality of symbols.
18. The method of claim 17 , wherein said feedback comprises a performance indicator associated with said plurality of symbols.
19. The method of claim 11 , wherein said one or more error patterns are the most-frequently-occurring error patterns for a system comprising said transmitter.
20. The method of claim 11 , comprising adjusting a response of a pulse shaping filter of said transmitter in conjunction with said adjusting said configuration of said symbol constellation.