Coding and modulation apparatus using non-uniform constellation
View Patent ↗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 coding and modulation apparatus, comprising:
encoder circuitry configured to encode input data into cell words; and
modulator circuitry configured to modulate the cell words into constellation values of a non-uniform constellation, wherein
the modulator circuitry uses the following quarter of the non-uniform constellation having a total number of M=64 constellation points and a code rate 6/15,
the constellation points are defined by a constellation position vector W0 . . . b-1 with b=M/4
w0
0.5656 + 0.9499i
w1
0.2750 + 1.0676i
w2
0.8202 + 1.2651i
w3
0.3011 + 1.4529i
w4
0.9500 + 0.5641i
w5
1.0666 + 0.2744i
w6
1.2657 + 0.8178i
w7
1.4521 + 0.3005i
w8
0.3004 + 0.5417i
w9
0.2430 + 0.5607i
w10
0.2094 + 0.3579i
w11
0.1946 + 0.3566i
w12
0.5410 + 0.3002i
w13
0.5596 + 0.2431i
w14
0.3569 + 0.2094i
w15
0.3553 + 0.1948i
the other three quarters are derived by symmetry from the quarter of a non-uniform constellation, and
bit positions of the non-uniform constellation are interchanged.
2. A demodulation and decoding apparatus, comprising:
a demodulator that demodulates constellation values of the non-uniform constellation used by the coding and modulation apparatus as claimed in claim 1 into cell words; and
a decoder that decodes the cell words into output data.
3. A receiving apparatus, comprising:
a receiver that receives one or more transmission streams;
a deconverter that deconverts the received one or more transmission streams into constellation values; and
the demodulation and decoding apparatus as claimed in claim 2 that demodulates and decodes the constellation values into the output data.
4. A coding and modulation method, comprising:
encoding input data into cell words; and
modulating, by circuitry, the cell words into constellation values of a non-uniform constellation, wherein
the modulating uses the following quarter of the non-uniform constellation having a total number of M=64 constellation points and a code rate 6/15,
the constellation points are defined by a constellation position vector W0 . . . b-1 with b=M/4
w0
0.5656 + 0.9499i
w1
0.2750 + 1.0676i
w2
0.8202 + 1.2651i
w3
0.3011 + 1.4529i
w4
0.9500 + 0.5641i
w5
1.0666 + 0.2744i
w6
1.2657 + 0.8178i
w7
1.4521 + 0.3005i
w8
0.3004 + 0.5417i
w9
0.2430 + 0.5607i
w10
0.2094 + 0.3579i
w11
0.1946 + 0.3566i
w12
0.5410 + 0.3002i
w13
0.5596 + 0.2431i
w14
0.3569 + 0.2094i
w15
0.3553 + 0.1948i
the other three quarters are derived by symmetry from the quarter of the non-uniform constellation, and
the bit positions of the non-uniform constellation are interchanged.
5. A demodulation and decoding method, comprising:
demodulating constellation values of the non-uniform constellation used by the coding and modulation method as claimed in claim 4 ; and
decoding the cell words into output data.
6. A demodulation and decoding apparatus, comprising:
demodulator circuitry configured to demodulate constellation values of a non-uniform constellation into cell words; and
decoder circuitry decode the cell words into output data, wherein
the demodulator circuitry uses the following quarter of the non-uniform constellation having a total number of M=64 constellation points and a code rate 6/15,
the constellation points are defined by a constellation position vector W0 . . . b-1 with b=M/4
w0
0.5656 + 0.9499i
w1
0.2750 + 1.0676i
w2
0.8202 + 1.2651i
w3
0.3011 + 1.4529i
w4
0.9500 + 0.5641i
w5
1.0666 + 0.2744i
w6
1.2657 + 0.8178i
w7
1.4521 + 0.3005i
w8
0.3004 + 0.5417i
w9
0.2430 + 0.5607i
w10
0.2094 + 0.3579i
w11
0.1946 + 0.3566i
w12
0.5410 + 0.3002i
w13
0.5596 + 0.2431i
w14
0.3569 + 0.2094i
w15
0.3553 + 0.1948i
the other three quarters are derived by symmetry from the quarter of the non-uniform constellation, and
bit positions of the non-uniform constellation are interchanged.
7. 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 the following quarter of the non-uniform constellation having a total number of M=64 constellation points and a code rate 6/15,
the constellation points are defined by a constellation position vector W0 . . . b-1 with b=M4
w0
0.5656 + 0.9499i
w1
0.2750 + 1.0676i
w2
0.8202 + 1.2651i
w3
0.3011 + 1.4529i
w4
0.9500 + 0.5641i
w5
1.0666 + 0.2744i
w6
1.2657 + 0.8178i
w7
1.4521 + 0.3005i
w8
0.3004 + 0.5417i
w9
0.2430 + 0.5607i
w10
0.2094 + 0.3579i
w11
0.1946 + 0.3566i
w12
0.5410 + 0.3002i
w13
0.5596 + 0.2431i
w14
0.3569 + 0.2094i
w15
0.3553 + 0.1948i
the other three quarters are derived by symmetry from the quarter of the non-uniform constellation, and
bit positions of the non-uniform constellation are interchanged.
8. The demodulation and decoding apparatus as claimed in claim 6 , wherein the following quarter represents cell words having a first two significant bits of zero.
9. The demodulation and decoding apparatus as claimed in claim 6 , wherein cells words demodulated from the constellation position vector W0 . . . b-1 represent cell words having a first two significant bits of zero
10. The demodulation and decoding apparatus as claimed in claim 6 , 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.
11. The demodulation and decoding apparatus as claimed in claim 6 , wherein the interchanged bit positions of the non-uniform constellation result in cell words having:
a value 000111 is demodulated from position w0,
a value 000110 is demodulated from position w1;
a value 000101 is demodulated from position w2;
a value 000100 is demodulated from position w3;
a value 000011 is demodulated from position w4;
a value 000010 is demodulated from position w5;
a value 000001 is demodulated from position w6;
a value 000000 is demodulated from position w7;
a value 001111 is demodulated from position w8;
a value 001110 is demodulated from position w9;
a value 001101 is demodulated from position w10;
a value 001100 is demodulated from position w11;
a value 001011 is demodulated from position w12;
a value 001010 is demodulated from position w13;
a value 001001 is demodulated from position w14; and
a value 001000 is demodulated from position w15.
12. The demodulation and decoding apparatus as claimed in claim 6 , wherein when a signal is received by receiver circuitry with a code rate different from 6/15, the demodulator circuitry uses different constellation points of a different non-uniform constellation.
13. The demodulation and decoding apparatus as claimed in claim 6 , wherein the demodulator circuitry makes soft decisions as to the constellation point from which a cell word is decoded.
14. An ATSC receiver comprising:
the demodulation and decoding apparatus as claimed in claim 6 .
15. A receiver comprising:
the demodulation and decoding apparatus as claimed in claim 6 , wherein
the decoder circuitry and demodulator circuitry are configured to operate on Bit Interleaved Coded Modulation (BICM) data.
16. The receiver as claimed in claim 15 , further comprising a Forward Error Correction decoder.
17. The demodulation and decoding method as claimed in claim 7 , wherein the following quarter represents cell words having a first two significant bits of zero.
18. The demodulation and decoding method as claimed in claim 7 , wherein cells 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 method as claimed in claim 7 , 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 method as claimed in claim 7 , wherein the interchanged bit positions of the non-uniform constellation result in cell words having:
a value 000111 is demodulated from position w0;
a value 000110 is demodulated from position w1;
a value 000101 is demodulated from position w2;
a value 000100 is demodulated from position w3;
a value 000011 is demodulated from position w4;
a value 000010 is demodulated from position w5;
a value 000001 is demodulated from position w6;
a value 000000 is demodulated from position w7;
a value 001111 is demodulated from position w8;
a value 001110 is demodulated from position w9;
a value 001101 is demodulated from position w10;
a value 001100 is demodulated from position w11;
a value 001011 is demodulated from position w12;
a value 001010 is demodulated from position w13;
a value 001001 is demodulated from position w14; and
a value 001000 is demodulated from position w15.
21. The demodulation and decoding method as claimed in claim 7 , further comprising making soft decisions as to the constellation point from which a cell word is decoded.