Coding and modulation apparatus using non-uniform constellation
A coding and modulation apparatus and method are presented. The apparatus comprises an encoder that encodes input data into cell words, and a modulator that modulates said cell words into constellation values of a non-uniform constellation. The modulator is configured to use, based on the total number M of constellation points of the constellation and the code rate, a non-uniform constellation from one or several groups of constellations each comprising one or more constellations.
1. A demodulation and decoding apparatus, comprising:
demodulator circuitry configured to demodulate constellation values of a constellation into cell words; and
decoder circuitry configured to decode the cell words into output data, wherein
the demodulator circuitry is configured to use two-hundred and fifty six constellation points associated with a code rate 12/15, wherein sixty four of the constellation points are defined by the following real and imaginary parts
1.1980 + 1.1541i
0.9192 + 1.2082i
1.2778 + 0.8523i
1.0390 + 0.9253i
0.6057 + 1.2200i
0.7371 + 1.4217i
0.6678 + 1.0021i
0.8412 + 0.9448i
1.2128 + 0.5373i
1.0048 + 0.5165i
1.4321 + 0.6343i
1.0245 + 0.7152i
0.6384 + 0.6073i
0.8175 + 0.5684i
0.6568 + 0.7801i
0.8311 + 0.7459i
0.1349 + 1.4742i
0.1105 + 1.2309i
0.0634 + 0.9796i
0.1891 + 1.0198i
0.4142 + 1.4461i
0.3323 + 1.2279i
0.4998 + 0.9827i
0.3467 + 1.0202i
0.0680 + 0.6501i
0.2016 + 0.6464i
0.0719 + 0.8075i
0.2088 + 0.8146i
0.4809 + 0.6296i
0.3374 + 0.6412i
0.4955 + 0.8008i
0.3431 + 0.8141i
1.2731 + 0.1108i
1.0794 + 0.0977i
1.5126 + 0.1256i
0.9029 + 0.0853i
0.5429 + 0.0694i
0.6795 + 0.0559i
0.5628 + 0.1945i
0.7326 + 0.1410i
1.2283 + 0.3217i
1.0269 + 0.3261i
1.4663 + 0.3716i
0.9085 + 0.2470i
0.6160 + 0.45491
0.7818 + 0.4247i
0.5938 + 0.3170i
0.7600 + 0.2850i
0.0595 + 0.0707i
0.1722 + 0.0706i
0.0599 + 0.2119i
0.1748 + 0.2114i
0.4134 + 0.0701i
0.2935 + 0.0705i
0.4231 + 0.2066i
0.2979 + 0.2100i
0.0638 + 0.5002i
0.1905 + 0.4966i
0.0612 + 0.3552i
0.1810 + 0.3533i
0.4630 + 0.4764i
0.3231 + 0.4895i
0.4416 + 0.3397i
0.3083 + 0.3490i
each constellation point representing one of sixty four binary values for one quarter of the two hundred and fifty six constellation points.
2. The demodulation and decoding apparatus as claimed in claim 1 , wherein positive values for both the real and the imaginary parts indicate cell words having a first two significant bits of zero.
3. The demodulation and decoding apparatus as claimed in claim 2 , wherein each cell word demodulated from the constellation points represent eight bit cell words comprising the first two significant bits of zero and the one of sixty four binary values.
4. The demodulation and decoding apparatus as claimed in claim 1 , wherein negative values of either or both of th real and imaginary parts of others of the two hundred and fifty six constellation points define the first two significant bits of a decoded cell word.
5. The demodulation and decoding apparatus as claimed in claim 1 , wherein when a signal is received by receiver circuitry with a code rate different from 12/15, the demodulator circuitry is configured to use different constellation points of a different non-uniform constellation.
6. The demodulation and decoding apparatus as claimed in claim 1 , wherein the demodulator circuitry is configured to make soft decisions as to a constellation point from which a cell word is decoded.
7. An Advanced Television Systems Committee (ATSC) receiver comprising the demodulation and decoding apparatus as claimed in claim 1 .
8. A receiver comprising:
the demodulation and decoding apparatus as claimed in claim 1 , wherein
the decoder circuitry and demodulator circuitry are configured to operate on Bit Interleaved Coded Modulation (BICM) data.
9. The receiver as claimed in claim 8 , comprising a Forward Error Correction decoder.
10. A demodulation and decoding method, comprising:
demodulating, by circuitry, constellation values of a non-uniform constellation into cell words; and
decoding the cell words into output data, wherein
the demodulating uses a following quarter of the non-uniform constellation having a total number of M=256 constellation points associated with a code rate 12/15, and
the constellation points are defined by a constellation position vector w0 . . . b−1 with b=M/4
w0
1.1980 + 1.1541i
w1
0.9192 + 1.2082i
w2
1.2778 + 0.8523i
w3
1.0390 + 0.9253i
w4
0.6057 + 1.2200i
w5
0.7371 + 1.4217i
w6
0.6678 + 1.0021i
w7
0.8412 + 0.9448i
w8
1.2128 + 0.5373i
w9
1.0048 + 0.5165i
w10
1.4321 + 0.6343i
w11
1.0245 + 0.7152i
w12
0.6384 + 0.6073i
w13
0.8175 + 0.5684i
w14
0.6568 + 0.7801i
w15
0.8311 + 0.7459i
w16
0.1349 + 1.4742i
w17
0.1105 + 1.2309i
w18
0.0634 + 0.9796i
w19
0.1891 + 1.0198i
w20
0.4142 + 1.4461i
w21
0.3323 + 1.2279i
w22
0.4998 + 0.9827i
w23
0.3467 + 1.0202i
w24
0.0680 + 0.6501i
w25
0.2016 + 0.6464i
w26
0.0719 + 0.8075i
w27
0.2088 + 0.8146i
w28
0.4809 + 0.6296i
w29
0.3374 + 0.6412i
w30
0.4955 + 0.8008i
w31
0.3431 + 0.8141i
w32
1.2731 + 0.1108i
w33
1.0794 + 0.0977i
w34
1.5126 + 0.1256i
w35
0.9029 + 0.0853i
w36
0.5429 + 0.0694i
w37
0.6795 + 0.0559i
w38
0.5628 + 0.1945i
w39
0.7326 + 0.1410i
w40
1.2283 + 0.3217i
w41
1.0269 + 0.3261i
w42
1.4663 + 0.3716i
w43
0.9085 + 0.2470i
w44
0.6160 + 0.45491
w45
0.7818 + 0.4247i
w46
0.5938 + 0.3170i
w47
0.7600 + 0.2850i
w48
0.0595 + 0.0707i
w49
0.1722 + 0.0706i
w50
0.0599 + 0.2119i
w51
0.1748 + 0.2114i
w52
0.4134 + 0.0701i
w53
0.2935 + 0.0705i
w54
0.4231 + 0.2066i
w55
0.2979 + 0.2100i
w56
0.0638 + 0.5002i
w57
0.1905 + 0.4966i
w58
0.0612 + 0.3552i
w59
0.1810 + 0.3533i
w60
0.4630 + 0.4764i
w61
0.3231 + 0.4895i
w62
0.4416 + 0.3397i
w63
0.3083 + 0.3490i
and the other three quarters are derived by symmetry from the quarter of the non-uniform constellation.
11. The demodulation and decoding method as claimed in claim 10 , wherein the following quarter represents cell words having a first two significant bits of zero.
12. The demodulation and decoding method as claimed in claim 10 , wherein the cell words demodulated from the constellation position vector w0 . . . b−1 represent cell words having a first two significant bits of zero.
13. The demodulation and decoding method as claimed in claim 10 , wherein the other three quarters of the non-uniform constellation represent constellation points which, when a cell word is demodulated therefrom have first significant bits of 01 or 10 or 11 according to the quarter of the non-uniform constellation from which they are demodulated.
14. The demodulation and decoding method as claimed in claim 10 , comprising making soft decisions as to a constellation point from which a cell word is decoded.
15. The demodulation and decoding method as claimed in claim 10 , wherein when a signal is received with a code rate different from 12/15, the demodulation and decoding method comprises using different constellation points of a different non-uniform constellation.
16. A demodulation and decoding apparatus, comprising:
demodulator circuitry configured to demodulate constellation values of a non-uniform constellation into cell words; and
decoder circuitry configured to decode the cell words into output data, wherein
the demodulator circuitry is configured to use a following quarter of the non-uniform constellation having a total number of M=256 constellation points assocated with a code rate 12/15, and
the constellation points are defined by a constellation position vector w0 . . . b−1 with b=M/4
w0
1.1980 + 1.1541i
w1
0.9192 + 1.2082i
w2
1.2778 + 0.8523i
w3
1.0390 + 0.9253i
w4
0.6057 + 1.2200i
w5
0.7371 + 1.4217i
w6
0.6678 + 1.0021i
w7
0.8412 + 0.9448i
w8
1.2128 + 0.5373i
w9
1.0048 + 0.5165i
w10
1.4321 + 0.6343i
w11
1.0245 + 0.7152i
w12
0.6384 + 0.6073i
w13
0.8175 + 0.5684i
w14
0.6568 + 0.7801i
w15
0.8311 + 0.7459i
w16
0.1349 + 1.4742i
w17
0.1105 + 1.2309i
w18
0.0634 + 0.9796i
w19
0.1891 + 1.0198i
w20
0.4142 + 1.4461i
w21
0.3323 + 1.2279i
w22
0.4998 + 0.9827i
w23
0.3467 + 1.0202i
w24
0.0680 + 0.6501i
w25
0.2016 + 0.6464i
w26
0.0719 + 0.8075i
w27
0.2088 + 0.8146i
w28
0.4809 + 0.6296i
w29
0.3374 + 0.6412i
w30
0.4955 + 0.8008i
w31
0.3431 + 0.8141i
w32
1.2731 + 0.1108i
w33
1.0794 + 0.0977i
w34
1.5126 + 0.1256i
w35
0.9029 + 0.0853i
w36
0.5429 + 0.0694i
w37
0.6795 + 0.0559i
w38
0.5628 + 0.1945i
w39
0.7326 + 0.1410i
w40
1.2283 + 0.3217i
w41
1.0269 + 0.3261i
w42
1.4663 + 0.3716i
w43
0.9085 + 0.2470i
w44
0.6160 + 0.45491
w45
0.7818 + 0.4247i
w46
0.5938 + 0.3170i
w47
0.7600 + 0.2850i
w48
0.0595 + 0.0707i
w49
0.1722 + 0.0706i
w50
0.0599 + 0.2119i
w51
0.1748 + 0.2114i
w52
0.4134 + 0.0701i
w53
0.2935 + 0.0705i
w54
0.4231 + 0.2066i
w55
0.2979 + 0.2100i
w56
0.0638 + 0.5002i
w57
0.1905 + 0.4966i
w58
0.0612 + 0.3552i
w59
0.1810 + 0.3533i
w60
0.4630 + 0.4764i
w61
0.3231 + 0.4895i
w62
0.4416 + 0.3397i
w63
0.3083 + 0.3490i
and the other three quarters are derived by symmetry from the quarter of the non-uniform constellation.
17. The demodulation and decoding apparatus as claimed in claim 16 , wherein the following quarter represents cell words having a first two significant bits of zero.
18. The demodulation and decoding apparatus as claimed in claim 16 , wherein the cell words demodulated from the constellation position vector w0 . . . b−1 represent cell words having a first two significant bits of zero.
19. The demodulation and decoding apparatus as claimed in claim 16 , wherein the other three quarters of the non-uniform constellation represent constellation points which, when a cell word is demodulated therefrom, have first significant bits of 01 or 10 or 11 according to the quarter of the non-uniform constellation from which they are demodulated.
20. The demodulation and decoding apparatus as claimed in claim 16 , wherein when a signal is received by receiver circuitry with a code rate different from 12/15, the demodulator circuitry is configured to use different constellation points of a different non-uniform constellation.
21. An Advanced Television Systems Committee (ATSC) receiver comprising the demodulation and decoding apparatus as claimed in claim 16 .
22. A demodulation and decoding method, comprising:
demodulating, by circuitry, constellation values of a constellation into cell words; and
decoding the cell words into output data, wherein the demodulating uses two-hundred and fifty six constellation points associated with a code rate 12/15, wherein sixty four of the constellation points are defined by the following real and imaginary parts:
1.1980 + 1.1541i
0.9192 + 1.2082i
1.2778 + 0.8523i
1.0390 + 0.9253i
0.6057 + 1.2200i
0.7371 + 1.4217i
0.6678 + 1.0021i
0.8412 + 0.9448i
1.2128 + 0.5373i
1.0048 + 0.5165i
1.4321 + 0.6343i
1.0245 + 0.7152i
0.6384 + 0.6073i
0.8175 + 0.5684i
0.6568 + 0.7801i
0.8311 + 0.7459i
0.1349 + 1.4742i
0.1105 + 1.2309i
0.0634 + 0.9796i
0.1891 + 1.0198i
0.4142 + 1.4461i
0.3323 + 1.2279i
0.4998 + 0.9827i
0.3467 + 1.0202i
0.0680 + 0.6501i
0.2016 + 0.6464i
0.0719 + 0.8075i
0.2088 + 0.8146i
0.4809 + 0.6296i
0.3374 + 0.6412i
0.4955 + 0.8008i
0.3431 + 0.8141i
1.2731 + 0.1108i
1.0794 + 0.0977i
1.5126 + 0.1256i
0.9029 + 0.0853i
0.5429 + 0.0694i
0.6795 + 0.0559i
0.5628 + 0.1945i
0.7326 + 0.1410i
1.2283 + 0.3217i
1.0269 + 0.3261i
1.4663 + 0.3716i
0.9085 + 0.2470i
0.6160 + 0.4549i
0.7818 + 0.4247i
0.5938 + 0.3170i
0.7600 + 0.2850i
0.0595 + 0.0707i
0.1722 + 0.0706i
0.0599 + 0.2119i
0.1748 + 0.2114i
0.4134 + 0.0701i
0.2935 + 0.0705i
0.4231 + 0.2066i
0.2979 + 0.2100i
0.0638 + 0.5002i
0.1905 + 0.4966i
0.0612 + 0.3552i
0.1810 + 0.3533i
0.4630 + 0.4764i
0.3231 + 0.4895i
0.4416 + 0.3397i
0.3083 + 0.3490i
each constellation point representing one of sixty four binary values for one quarter of the two hundred and fifty six constellation points.