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

• US 10,341,046 B2
• Filed: 04/05/2017
• Issued: 07/02/2019
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Arambepola, Bernard, Tal, Noam, Gamage, Sahan S., Hewavithana, Thushara, Shulman, Shaul
• Primary Examiner(s): Wei, Siren
• Application Number:
  US15/479,878
• Publication Number:
  US 20170272201A1
• Time in Patent Office: 818 Days
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/0008 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 Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 5/0046 Determination of how many bits are transmitted on different sub-channels

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.

Claims

1. A cable modem including:

an inverse multiplexer to distribute a data bit stream into multiple segments;

a constellation mapper to map each of the segments to a respective subset of subcarriers to yield constellation symbols, wherein;

the constellation mapper is to modulate each subset of subcarriers using a respective modulation scheme selected from multiple selectable modulation schemes, wherein the multiple selectable modulation schemes include a pair of QAM constellations including 1024 QAM and 2048 QAM;

the constellation mapper is to modulate subsets of the subcarriers based on predetermined selectable combinations of modulation schemes; and

each subset of subcarriers includes Orthogonal Frequency Division Multiple Access (OFDMA) subcarriers; and

the cable modem to cause transmission of a Radio Frequency (RF) signal, the RF signal based on the constellation symbols.

2. The cable modem of claim 1, further including a block encoder to block encode the data bit stream to generate a block encoded data bit stream, the constellation mapper to map the block encoded data bit stream.

3. The cable modem of claim 2, wherein the block encoder is to block encode the data bit stream using Low-Density Parity Check (LDPC) Forward Error Correction (FEC) coding.

4. The cable modem of claim 3, wherein the block encoder is to select a FEC code rate for the FEC coding from multiple selectable FEC code rates, the multiple selectable FEC code rates including a maximum selectable code rate.

5. The cable modem of claim 1, wherein the modulation schemes include non-square Quadrature Amplitude Modulation (QAM) constellations.

6. The cable modem of claim 1, wherein the multiple selectable modulation schemes include Quadrature Amplitude Modulation (QAM) constellations including 128 QAM, 256 QAM, 512 QAM, 1024 QAM, 2048 QAM and 4096 QAM.

7. The cable modem of claim 6, wherein the multiple selectable modulation schemes further include pairs of QAM constellations including:

128 QAM and 256 QAM;

256 QAM and 512 QAM;

512 QAM and 1024 QAM; and

2048 QAM and 4096 QAM.

8. The cable modem of claim 1, further including an interleaver to add pilots to the constellation symbols and to interleave the constellation symbols in at least one of time and frequency.

9. The cable modem of claim 8, further including a pre-equalizer to pre-distort the constellation symbols after interleaving to generate pre-equalized symbols to compensate for a channel response associated with a transmission channel for a transmission of the RF signal.

10. The cable modem of claim 9, further including an Inverse Fast Fourier Transform (IFFT) module to transform each of the pre-equalized symbols into a time domain to generate time domain symbols.

11. The cable modem of claim 10, further including a cyclic prefix (CP) and windowing block to prepend a cyclic prefix and to perform a windowing operation on the time domain symbols.

12. A product comprising one or more tangible computer-readable non-transitory storage media comprising computer-executable instructions operable to, when executed by at least one computer processor, cause the at least one computer processor to implement operations at a cable modem, the operations comprising:

distributing a data bit stream into multiple segments;

mapping each of the segments to a respective subset of subcarriers to yield constellation symbols, mapping including modulating each subset of subcarriers using a respective modulation scheme selected from multiple selectable modulation schemes, wherein the multiple selectable modulation schemes include a pair of QAM constellations including 1024 QAM and 2048 QAM, and wherein each subset of subcarriers includes Orthogonal Frequency Division Multiple Access (OFDMA) subcarriers, mapping further including modulating subsets of the subcarriers based on predetermined selectable combinations of modulation schemes; and

causing transmission of a Radio Frequency (RF) signal, the RF signal based on the constellation symbols.

13. The product of claim 12, the operations further including block encoding the data bit stream to generate a block encoded data bit stream, mapping the data bit stream including mapping the block encoded data bit stream.

14. The product of claim 13, wherein block encoding the data bit stream includes using Low-Density Parity Check (LDPC) Forward Error Correction (FEC) coding.

15. The product of claim 14, wherein block encoding the data bit stream includes selecting a FEC code rate for the FEC coding from multiple selectable FEC code rates, the multiple selectable FEC code rates including a maximum selectable code rate.

16. The product of claim 12, wherein the modulation schemes include non-square Quadrature Amplitude Modulation (QAM) constellations.

17. The product of claim 12, wherein the multiple selectable modulation schemes include Quadrature Amplitude Modulation (QAM) constellations including 128 QAM, 256 QAM, 512 QAM, 1024 QAM, 2048 QAM and 4096 QAM.

18. The product of claim 17, wherein the multiple selectable modulation schemes further include pairs of QAM constellations including:

128 QAM and 256 QAM;

256 QAM and 512 QAM;

512 QAM and 1024 QAM; and

2048 QAM and 4096 QAM.

19. The product of claim 12, the operations further including adding pilots to the constellation symbols and interleaving the constellation symbols in at least one of time and frequency.

20. The product of claim 19, the operations further including pre-distorting the constellation symbols after interleaving to generate pre-equalized symbols to compensate for a channel response associated with a transmission channel for a transmission of the RF signal.

21. The product of claim 20, the operations further including using an Inverse Fast Fourier Transform (IFFT) module to transform each of the pre-equalized symbols into a time domain to generate time domain symbols.

22. The product of claim 21, the operations further including prepending a cyclic prefix and performing a windowing operation on the time domain symbols.

23. A method to be performed at a wireless modem, the method including:

distributing a data bit stream into multiple segments;

mapping each of the segments to a respective subset of subcarriers to yield constellation symbols, mapping including modulating each subset of subcarriers using a respective modulation scheme selected from multiple selectable modulation schemes, wherein the multiple selectable modulation schemes include a pair of QAM constellations including 1024 QAM and 2048 QAM, and wherein each subset of subcarriers includes Orthogonal Frequency Division Multiple Access (OFDMA) subcarriers, mapping further including modulating subsets of the subcarriers based on predetermined selectable combinations of modulation schemes; and

causing transmission of a Radio Frequency (RF) signal, the RF signal based on the constellation symbols.

24. The method of claim 23, further including block encoding the data bit stream to generate a block encoded data bit stream, mapping the data bit stream including mapping the block encoded data bit stream.

25. The method of claim 24, wherein block encoding the data bit stream includes using Low-Density Parity Check (LDPC) coding and Forward Error Correction (FEC) coding.

26. The method of claim 25, wherein block encoding the data bit stream includes selecting a FEC code rate for the FEC coding from multiple selectable FEC code rates, the multiple selectable FEC code rates including a maximum selectable code rate.

27. The method of claim 23, wherein the modulation schemes include non-square Quadrature Amplitude Modulation (QAM) constellations.

28. The method of claim 23, wherein the multiple selectable modulation schemes include Quadrature Amplitude Modulation (QAM) constellations including 128 QAM, 256 QAM, 512 QAM, 1024 QAM, 2048 QAM and 4096 QAM.

29. The method of claim 28, wherein the multiple selectable modulation schemes further include pairs of QAM constellations including:

128 QAM and 256 QAM;

256 QAM and 512 QAM;

512 QAM and 1024 QAM; and

2048 QAM and 4096 QAM.

30. The method of claim 23, further including adding pilots to the constellation symbols and interleaving the constellation symbols in at least one of time and frequency.

31. The method of claim 30 further including pre-distorting the constellation symbols after interleaving to generate pre-equalized symbols to compensate for a channel response associated with a transmission channel for a transmission of the RF signal.

32. The method of claim 31, including using an Inverse Fast Fourier Transform (IFFT) module to transform each of the pre-equalized symbols into a time domain to generate time domain symbols.

33. The method of claim 32, including prepending a cyclic prefix and performing a windowing operation on the time domain symbols.