Configurable constellation mapping to control spectral efficiency versus signal-to-noise ratio

Patent metadata

Field	Value
Publication number	US-11075713-B2
Application number	US-201916714640-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Mar 4, 2013
Publication date	Jul 27, 2021
Grant date	Jul 27, 2021

Abstract

Mixed mode constellation mapping to map a data block to a block of sub-carriers based on a configurable set of one or more constellation mapping schemes, and corresponding mixed mode least likelihood ratio (LLR) de-mapping based on the configurable set of one or more modulation schemes. The set may be configurable to include multiple modulation schemes to provide to a SEvSNR measure that is a non-weighted or weighted average of SEvSNR measures of the multiple modulation schemes. Mixed mode constellation mapping may be useful be configurable to control spectral efficiency versus SNR (SEvSNR) over a range of SNR with relatively fine SNR granularity, and may be configurable to control SEvSNR over a range of SNR at a fixed FEC code rate, which may include a highest available or highest permitted code rate.

First claim

What is claimed is:

1. A cable modem modulation apparatus, comprising:
a constellation mapper to assign sub-carriers representing a bit stream amongst Quadrature Amplitude Modulation (QAM) constellations including a square QAM constellation and a non-square QAM constellation;
a modulator to modulate the sub-carriers assigned to the square QAM constellation and the non-square QAM constellation to yield constellation symbols of mixed-modulation data sub-carriers, wherein the data sub-carriers include Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers;
an interleaver to interleave the constellation symbols in time and frequency;
a Fourier Transform module to transform the constellation symbols from the interleaver into a time domain to generate time domain symbols; and
a cyclic prefix (CP) and windowing block to prepend a cyclic prefix and to perform a windowing operation on the time domain symbols.

2. The apparatus of claim 1 , wherein the constellation mapper to assign unequal numbers of the sub-carriers to a first and second QAM constellation.

3. The apparatus of claim 2 , wherein the first QAM constellation is the square QAM constellation and the second QAM constellation is the non-square QAM constellation.

4. The apparatus of claim 1 , wherein the constellation mapper further to adjust a ratio of the sub-carriers amongst the QAM constellations.

5. The apparatus of claim 4 , wherein the constellation mapper further to adjust the ratio of the sub-carriers amongst the square and non-square QAM constellations.

6. The apparatus of claim 1 , wherein the non-square QAM constellation is selected from the group consisting of 128, 512 QAM constellations and a 2048 QAM constellation.

7. The apparatus of claim 6 , wherein the square QAM constellation is selected from the group consisting of 16, 64, 256, 1024 QAM constellations and a 4096 QAM constellation.

8. The apparatus of claim 1 , wherein the constellation mapper to selectively assign the sub-carriers to the square QAM constellation and the non-square QAM constellation that increases signal to noise ratio (SNR) efficiency (SEvSNR).

9. The apparatus of claim 1 , wherein the constellation mapper to assign the sub-carriers amongst a mix of selectable square and non-square QAM constellation mapper units.

10. The apparatus of claim 1 , wherein the constellation mapper to provide segments of the bit stream to selected constellation mappers.

11. The apparatus of claim 10 , wherein the constellation mapper to map the bit stream to the respective square QAM constellation and the non-square QAM constellation.

12. The apparatus of claim 1 , wherein the constellation mapper includes an inverse multiplexer that assigns the sub-carriers.

13. A cable modem transceiver, comprising:
constellation mapper means to assign sub-carriers representing a bit stream amongst Quadrature Amplitude Modulation (QAM) constellations including a square QAM constellation and a non-square QAM constellation;
a modulator to modulate the sub-carriers assigned to the square QAM constellation and the non-square QAM constellation to yield constellation symbols of mixed-modulation data sub-carriers, wherein the data sub-carriers include Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers;
an interleaver to interleave the constellation symbols in time and frequency;
a Fourier Transform module to transform the constellation symbols from the interleaver into a time domain to generate time domain symbols; and
a cyclic prefix (CP) and windowing block to prepend a cyclic prefix and to perform a windowing operation on the time domain symbols.

14. The cable modem transceiver of claim 13 , wherein the constellation mapper means to assign unequal numbers of the sub-carriers to a first and second QAM constellation.

15. The cable modem transceiver of claim 14 , wherein the first QAM constellation is the square QAM constellation and the second QAM constellation is the non-square QAM constellation.

16. The cable modem transceiver of claim 13 , wherein the constellation mapper means further to adjust a ratio of the sub-carriers amongst the QAM constellations.

17. The cable modem transceiver of claim 13 , wherein the non-square QAM constellation is selected from the group consisting of 128, 512 QAM constellations and a 2048 QAM constellation.

18. The cable modem transceiver of claim 17 , wherein the square QAM constellation is selected from the group consisting of 16, 64, 256, 1024 QAM constellations and a 4096 QAM constellation.

19. The cable modem transceiver of claim 13 , wherein the constellation mapper means to assign the sub-carriers amongst a mix of selectable square and non-square QAM constellation mapper units.

20. The cable modem transceiver of claim 13 , wherein the constellation mapper means includes an inverse multiplexer that assigns the sub-carriers.

21. A method for modulating sub-carriers of a cable modem comprising:
assigning sub-carriers representing a bit stream amongst Quadrature Amplitude Modulation (QAM) constellations including a square QAM constellation and a non-square QAM constellation;
modulating the sub-carriers assigned to the square QAM constellation and the non-square QAM constellation to yield constellation symbols of mixed-modulation data sub-carriers, wherein the data sub-carriers include Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers;

interleaving the constellation symbols in time and frequency;
transforming the constellation symbols from the interleaver into a time domain to generate time domain symbols; and
prepending a cyclic prefix and performing a windowing operation on the time domain symbols.

22. The method of claim 21 , wherein the constellation mapper to assign unequal numbers of the sub-carriers to a first and second QAM constellation.

23. The method of claim 21 , further comprising selecting the non-square QAM constellation from the group consisting of 128, 512 QAM constellations and a 2048 QAM constellation.

24. The method of claim 22 , further comprising selecting the square QAM constellation from the group consisting of a 16, 64, 256, 1024 QAM constellations and a 4096 QAM constellation.

25. A non-transitory computer-readable medium comprising instructions stored thereon, that if executed by a processor, cause the processor to:
assign sub-carriers representing a bit stream amongst Quadrature Amplitude Modulation (QAM) constellations including a square QAM constellation and a non-square QAM constellation;
modulate the sub-carriers assigned to the square QAM constellation and the non-square QAM constellation to yield constellation symbols of mixed-modulation data sub-carriers, wherein the data sub-carriers include Orthogonal Frequency Division Multiplexing (OFDM) sub-carriers;

interleave the constellation symbols in time and frequency;
transform the constellation symbols from the interleaver into a time domain to generate time domain symbols; and
prepend a cyclic prefix and perform a windowing operation on the time domain symbols.

26. The computer-readable medium of claim 25 , wherein the constellation mapper to assign unequal numbers of the sub-carriers to a first and second QAM constellation.

27. The computer-readable medium of claim 25 , further to select the non-square QAM constellation from the group consisting of 128, 512 QAM constellations and a 2048 QAM constellation.

Assignees

• Intel Corp

Inventors

• Arambepola Bernard
• Tal Noam
• Gamage Sahan S
• Hewavithana Thushara
• Shulman Shaul

Classifications

• H04L27/2634 Primary

  Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation · CPC title

• H04L1/004 Primary

  by using forward error control (H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00) · CPC title

• H04L1/0041

  Arrangements at the transmitter end · CPC title

• H04L27/0008

  arrangements for allowing a transmitter or receiver to use more than one type of modulation (negotiating modulation type for two-way transmission paths H04L5/1453) · CPC title

• H04L5/0046

  Determination of the number of bits transmitted on different sub-channels · CPC title