Configurable Constellation Mapping to Control Spectral Efficiency Versus Signal-to-Noise Ratio

• US 20140247782A1
• Filed: 03/04/2014
• Published: 09/04/2014
• 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
• Granted Patent: US 9,634,795 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• 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. An apparatus, comprising:

a mixed mode constellation mapper to map a data block to a block of sub-carriers based on a set of one or more modulation schemes, wherein the set of one or more modulation schemes is configurable to control spectral efficiency versus signal-to-noise ratio (SEvSNR) of over a range of SNR.

2. The apparatus of claim 1, wherein the set is configurable to include multiple modulation schemes to provide a SEvSNR measure that is an average of SEvSNR measures of the multiple modulation schemes.

3. The apparatus of claim 2, wherein the set is configurable to include multiple modulation schemes to provide a SEvSNR measure that is a non-weighted average of SEvSNR measures of the multiple modulation schemes.

4. The apparatus of claim 2, wherein the set is configurable to include multiple modulation schemes to provide a SEvSNR measure that is a weighted average of SEvSNR measures of the multiple modulation schemes.

5. The apparatus of claim 2, wherein the set is configurable with respect to a ratio of sub-carriers of the multiple modulation schemes to control the SEvSNR measure over a range SNR.

6. The apparatus of claim 1, wherein the set is configurable to include a selectable one of:

a first modulation scheme to provide a first SEvSNR measure;

a second modulation scheme to provide a second SEvSNR measure; and

a combination of the first and second modulation schemes to provide a third SEvSNR measure that is between the first and second SEvSNR measures.

7. The apparatus of claim 1, wherein the set is configurable to include one or more of multiple quadrature amplitude modulation (QAM) schemes, each associated with a respective constellation map.

8. The apparatus of claim 1, further including a forward error correction (FEC) encoder to provide a FEC-encoded data block, wherein the mixed mode constellation mapper is configured to map a FEC-encoded data block to the block of sub-carriers, and wherein the mixed mode constellation mapper is configurable to control SEvSNR over a range of SNR at a fixed FEC code rate.

9. The apparatus of claim 8, wherein the FEC encoder is configured to block-encode at a highest one of multiple selectable code rates.

10. The apparatus of claim 9, wherein:

the FEC encoder includes a low-density parity-check (LDPC) outer encoder configured to block-encode with a code rate 8/9, and a BCH encoder to block-encode with an outer 12-bit error correcting BCH code and 168 parity bits; and

the set of one or more modulation schemes is configurable to include one or more of multiple non-square quadrature amplitude modulation (QAM) schemes.

11. The apparatus of claim 10, wherein the mixed mode constellation mapper is configurable to control SEvSNR over a range of SNR in increments of 1.5 dB SNR.

12. The apparatus of claim 1, further including a transceiver that includes a transmit path and a receive path, wherein the transmit path includes the mixed mode constellation mapper and wherein the receive path includes:

a demodulator to demodulate multiple sub-carriers from a receive signal;

a mixed mode least likelihood ratio (LLR) de-mapper to compute LLRs for a block of the demodulated sub-carriers based a set of one or more modulation schemes, wherein the mixed mode LLR de-mapper is configurable with respect to the set of one or more modulation schemes; and

a FEC block decoder to decode a bit stream based on the LLRs.

13. A non-transitory computer-readable medium encoded with a computer program, including instructions to cause a processor to:

map a data block to a block of sub-carriers based on a set of one or more modulation schemes; and

configure the set of one or more modulation schemes to control spectral efficiency versus signal-to-noise ratio (SEvSNR) of over a range of SNR.

14. The computer-readable medium of claim 13, further including instructions to cause the processor to configure the set to include multiple modulation schemes to provide a SEvSNR measure that is an average of SEvSNR measures of the multiple modulation schemes.

15. The computer-readable medium of claim 14, further including instructions to cause the processor to configure the set to include multiple modulation schemes to provide a SEvSNR measure that is a non-weighted average of SEvSNR measures of the multiple modulation schemes.

16. The computer-readable medium of claim 14, further including instructions to cause the processor to configure the set to include multiple modulation schemes to provide a SEvSNR measure that is a weighted average of SEvSNR measures of the multiple modulation schemes.

17. The computer-readable medium of claim 14, further including instructions to cause the processor to configure a ratio of sub-carriers of the multiple modulation schemes to control the SEvSNR measure over a range SNR.

18. The computer-readable medium of claim 13, further including instructions to cause the processor to configure the set include one of:

a first modulation scheme to provide a first SEvSNR measure;

a second modulation scheme to provide a second SEvSNR measure; and

a combination of the first and second modulation schemes to provide a third SEvSNR measure that is between the first and second SEvSNR measures.

19. The computer-readable medium of claim 13, further including instructions to cause the processor to configure the set to include one or more of multiple quadrature amplitude modulation (QAM) schemes, each associated with a respective constellation map.

20. The computer-readable medium of claim 14, further including instructions to cause the processor to:

block-encode a bit stream with a forward error correction (FEC) to provide a FEC-encoded data block;

map the FEC-encoded data block to the block of sub-carriers; and

manage the set to control SEvSNR over a range of SNR at a fixed FEC code rate.