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 said cell words into constellation values of a non-uniform constellation, wherein
the modulator circuitry uses the following quarter of a non-uniform constellation having a total number of M=64 constellation points and a code rate 8/15,
the constellation points are defined by a constellation position vector W0 . . . b−1 with b=M/4
w0
0.2920 + 1.4827i
w1
0.8411 + 1.2563i
w2
0.2174 + 1.0211i
w3
0.5702 + 0.8798i
w4
1.4827 + 0.2920i
w5
1.2563 + 0.8410i
w6
1.0211 + 0.2174i
w7
0.8798 + 0.5702i
w8
0.1475 + 0.3040i
w9
0.1691 + 0.3028i
w10
0.1871 + 0.6855i
w11
0.3563 + 0.6126i
w12
0.3040 + 0.1475i
w13
0.3028 + 0.1691i
w14
0.6855 + 0.1871i
w15
0.6126 + 0.3563i
and the other three quarters are derived by symmetry from the said quarter of the non-uniform constellation and wherein bit positions of the non-uniform constellation are interchanged.
2. A demodulation and decoding apparatus, comprising:
a demodulator that demodulates constellation values of a non-uniform constellation used by the coding and modulation apparatus as claimed in claim 1 into said cell words; and
a decoder that decodes said 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 said constellation values into output data.
4. 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 8/15, and
the constellation points are defined by a constellation position vector W0 . . . b−1 with b=M/4
w0
0.2920 + 1.4827i
w1
0.8411 + 1.2563i
w2
0.2174 + 1.0211i
w3
0.5702 + 0.8798i
w4
1.4827 + 0.2920i
w5
1.2563 + 0.8410i
w6
1.0211 + 0.2174i
w7
0.8798 + 0.5702i
w8
0.1475 + 0.3040i
w9
0.1691 + 0.3028i
w10
0.1871 + 0.6855i
w11
0.3563 + 0.6126i
w12
0.3040 + 0.1475i
w13
0.3028 + 0.1691i
w14
0.6855 + 0.1871i
w15
0.6126 + 0.3563i
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.
5. The demodulation and decoding apparatus as claimed in claim 4 , wherein the following quarter represents cell words having a first two significant bits of zero.
6. The demodulation and decoding apparatus as claimed in claim 4 , wherein the cells words demodulated from the constellation position vector W0 . . . b−1 represent cell words having a first two significant bits of zero.
7. The demodulation and decoding apparatus as claimed in claim 4 , 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.
8. The demodulation and decoding apparatus as claimed in claim 4 , wherein the interchanged bit positions of the non-uniform constellation result in cell words having:
a value 000100 that is demodulated from position w0;
a value 000101 that is demodulated from the position w1;
a value 000110 that is demodulated from the position w2;
a value 000111 that is demodulated from the position w3;
a value 000000 that is demodulated from the position w4;
a value 000001 that is demodulated from the position w5;
a value 000010 that is demodulated from the position w6;
a value 000011 that is demodulated from the position w7;
a value 001100 that is demodulated from the position w8;
a value 001101 that is demodulated from the position w9;
a value 001110 that is demodulated from the position w10;
a value 001111 that is demodulated from the position w11;
a value 001000 that is demodulated from the position w12;
a value 001001 that is demodulated from the position w13;
a value 001010 that is demodulated from the position w14; and
a value 001011 that is demodulated from the position w15.
9. The demodulation and decoding apparatus as claimed in claim 4 , wherein when a signal is received by receiver circuitry with a code rate different from 8/15, the demodulator circuitry uses different constellation points of a different non-uniform constellation.
10. The demodulation and decoding apparatus as claimed in claim 4 , wherein the demodulator circuitry makes soft decisions as to the constellation point from which a cell word is decoded.
11. An Advanced Television Systems Committee (ATSC) receiver comprising:
the demodulation and decoding apparatus as claimed in claim 4 .
12. A receiver comprising:
the demodulation and decoding apparatus as claimed in claim 4 , wherein
the decoder circuitry and demodulator circuitry are configured to operate on Bit Interleaved Coded Modulation (BICM) data.
13. The receiver as claimed in claim 9 , further comprising a Forward Error Correction decoder.
14. 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 8/15,
the constellation points are defined by a constellation position vector W0 . . . b−1 with b=M/4
w0
0.2920 + 1.4827i
w1
0.8411 + 1.2563i
w2
0.2174 + 1.0211i
w3
0.5702 + 0.8798i
w4
1.4827 + 0.2920i
w5
1.2563 + 0.8410i
w6
1.0211 + 0.2174i
w7
0.8798 + 0.5702i
w8
0.1475 + 0.3040i
w9
0.1691 + 0.3028i
w10
0.1871 + 0.6855i
w11
0.3563 + 0.6126i
w12
0.3040 + 0.1475i
w13
0.3028 + 0.1691i
w14
0.6855 + 0.1871i
w15
0.6126 + 0.3563i
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.
15. The demodulation and decoding method as claimed in claim 14 , wherein the following quarter represents cell words having a first two significant bits of zero.
16. The demodulation and decoding method as claimed in claim 14 , wherein the cells words demodulated from the constellation position vector W0 . . . b−1 represent cell words having a first two significant bits of zero.
17. The demodulation and decoding method as claimed in claim 14 , 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.
18. The demodulation and decoding method as claimed in claim 17 , wherein the interchanged bit positions of the non-uniform constellation result in cell words having:
a value 000100 that is demodulated from position w0,
a value 000101 that is demodulated from the position w1;
a value 000110 that is demodulated from the position w2;
a value 000111 that is demodulated from the position w3;
a value 000000 that is demodulated from the position w4;
a value 000001 that is demodulated from the position w5;
a value 000010 that is demodulated from the position w6;
a value 000011 that is demodulated from the position w7;
a value 001100 that is demodulated from the position w8;
a value 001101 that is demodulated from the position w9;
a value 001110 that is demodulated from the position w10;
a value 001111 that is demodulated from the position w11;
a value 001000 that is demodulated from the position w12;
a value 001001 that is demodulated from the position w13;
a value 001010 that is demodulated from the position w14; and
a value 001011 that is demodulated from the position w15.
19. The demodulation and decoding method as claimed in claim 14 , further comprising making soft decisions as to the constellation point from which a cell word is decoded.
20. 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 8/15,
the constellation points including:
0.2920+1.4827i,
0.2174+1.0211i,
0.5702+0.8798i,
1.4827+0.2920i,
1.2563+0.8410i,
1.0211+0.2174i,
0.8798+0.5702i,
0.1475+0.3040i,
0.1691+0.3028i,
0.1871+0.6855i,
0.3563+0.6126i,
0.3040+0.1475i,
0.3028+0.1691i,
0.6855+0.1871i, and
0.6126+0.3563i
and the other three quarters are derived by symmetry from the quarter of the non-uniform constellation.