Method and system for providing long and short block length low density parity check (LDPC) codes

• US 20050091570A1
• Filed: 10/22/2004
• Published: 04/28/2005
• Est. Priority Date: 10/27/2003
• Status: Active Grant

• Current Assignee: DTVG Licensing, Inc. (AT&T, Inc.)
• Original Assignee: The DIRECTV Group, Inc. (AT&T, Inc.)
• Inventors: Sun, Feng-Wen, Lee, Lin-Nan, Eroz, Mustafa
• Granted Patent: US 7,376,883 B2
• Time in Patent Office: Days
• US Class Current: 714/800
• CPC Class Codes: H03M 13/1137 Partly parallel processing, i.e. sub-blocks or sub-groups of nodes being processed in parallel
• CPC Class Codes: H03M 13/1165 QC-LDPC codes as defined for the digital video broadcasting [DVB] specifications, e.g. DVB-Satellite [DVB-S2]
• CPC Class Codes: H03M 13/152 Bose-Chaudhuri-Hocquenghem [BCH] codes
• CPC Class Codes: H03M 13/2906 using block codes H03M13/2957 takes precedence

Abstract

An approach is provided for generating Low Density Parity Check (LDPC) codes. An LDPC encoder generates a LDPC code with an outer Bose Chaudhuri Hocquenghem (BCH) code. For ⅓ rate, the relevant parameters are as follows: q=120, n_ldpc=64,800, k_ldpc=n_BCH=21600, k_BCH=21408 (12 bit error correcting BCH). For ¼ rate, the LDPC code has the following relevant parameters: q=135, n_ldpc=64,800, k_ldpc=n_BCH=16200, k_BCH=16008 (12 bit error correcting BCH). For ⅖ rate, the following parameters exist: q=108, n_ldpc=64800, k_ldpc=n_BCH=25920, k_BCH=25728 (12 bit error correcting BCH). The above approach has particular application in digital video broadcast services over satellite.

Claims

1. A method for encoding, comprising:

receiving information bits; and

generating, based on the information bits, parity bits of a Low Density Parity Check (LDPC) code according to one of a code rate of ⅓

, a code rate of ¼

, or a code rate of ⅖

associated with respective tables each specifying address of parity bit accumulators,

Address of Parity Bit Accumulators (Rate ⅓

)34903 20927 32093 1052 25611 16093 16454 5520 506 37399 1851821120 11636 14594 22158 14763 15333 6838 22222 37856 14985 3104118704 32910 17449 1665 35639 16624 12867 12449 10241 11650 2562234372 19878 26894 29235 19780 36056 20129 20029 5457 8157 3555421237 7943 13873 14980 9912 7143 35911 12043 17360 37253 2558811827 29152 21936 24125 40870 40701 36035 39556 12366 19946 2907216365 35495 22686 11106 8756 34863 19165 15702 13536 40238 446540034 40590 37540 17162 1712 20577 14138 31338 19342 9301 393753211 1316 33409 28670 12282 6118 29236 35787 11504 30506 195585100 24188 24738 30397 33775 9699 6215 3397 37451 34689 231267571 1058 12127 27518 23064 11265 14867 30451 28289 2966 1166015334 16867 15160 38343 3778 4265 39139 17293 26229 42604 1348631497 1365 14828 7453 26350 41346 28643 23421 8354 16255 1105524279 15687 12467 13906 5215 41328 23755 20800 6447 7970 280333262 39843 5363 22469 38091 28457 36696 34471 23619 2404 2422941754 1297 18563 3673 39070 14480 30279 37483 7580 29519 3051939831 20252 18132 20010 34386 7252 27526 12950 6875 43020 3156639069 18985 15541 40020 16715 1721 37332 39953 17430 32134 2916210490 12971 28581 29331 6489 35383 736 7022 42349 8783 6767 1187121675 10325 11548 25978 431 24085 1925 10602 28585 12170 1515634404 8351 13273 20208 5800 15367 21764 16279 37832 34792 2125034192 7406 41488 18346 29227 26127 25493 704839948 28229 2489917408 14274 3899338774 15968 2845941404 27249 2742541229 6082 4311413957 4979 406543093 3438 3499234082 6172 2876042210 34141 4102114705 17783 1013441755 39884 2277314615 15593 164229111 37061 398609579 33552 63312951 21137 3960838244 27361 294172939 10172 3647929094 5357 192249562 24436 2863740177 2326 135046834 21583 4251640651 42810 2570931557 32138 3814218624 41867 3929637560 14295 162456821 21679 3157025339 25083 220818047 697 352689884 17073 1999526848 35245 839018658 16134 1480712201 32944 503525236 1216 3898642994 24782 868128321 4932 342494107 29382 3212422157 2624 1446838788 27081 79364368 26148 1057825353 4122 39751Address of Parity Bit Accumulators (Rate ¼

)23606 36098 1140 28859 18148 18510 6226 540 42014 20879 2380247088 16419 24928 16609 17248 7693 24997 42587 16858 34921 2104237024 20692 1874 40094 18704 14474 14004 11519 13106 28826 3866922363 30255 31105 22254 40564 22645 22532 6134 9176 39998 238928937 15608 16854 31009 8037 40401 13550 19526 41902 28782 1330432796 24679 27140 45980 10021 40540 44498 13911 22435 32701 1840539929 25521 12497 9851 39223 34823 15233 45333 5041 44979 4571042150 19416 1892 23121 15860 8832 10308 10468 44296 3611 148037581 32254 13817 6883 32892 40258 46538 11940 6705 21634 2815043757 895 6547 20970 28914 30117 25736 41734 11392 22002 573927210 27828 34192 37992 10915 6998 3824 42130 4494 35739 85151191 13642 30950 25943 12673 16726 34261 31828 3340 8747 3922518979 17058 43130 4246 4793 44030 19454 29511 47929 15174 2433319354 16694 8381 29642 46516 32224 26344 9405 18292 12437 2731635466 41992 15642 5871 46489 26723 23396 7257 8974 3156 3742044823 35423 13541 42858 32008 41282 38773 26570 2702 27260 469741469 20887 27426 3855322152 24261 829719347 9978 2780234991 6354 3356129782 30875 295239278 48512 1434938061 4165 438788548 33172 3441022535 28811 2395020439 4027 2418638618 8187 3094735538 43880 214597091 45616 150635505 9315 2190836046 32914 118367304 39782 3372116905 29962 1298011171 23709 2246034541 9937 4450014035 47316 881515057 45482 2446130518 36877 8797583 13364 24332448 27056 468212083 31378 216701159 18031 222117028 38715 935017343 24530 2957446128 31039 3281820373 36967 1834546685 20622 32806Address of Parity Bit Accumulators (Rate ⅖

)5650 4143 8750 583 6720 8071 635 1767 1344 6922 738 66585696 1685 3207 415 7019 5023 5608 2605 857 6915 1770 80163992 771 2190 7258 8970 7792 1802 1866 6137 8841 886 19314108 3781 7577 6810 9322 8226 5396 5867 4428 8827 7766 22544247 888 4367 8821 9660 324 5864 4774 227 7889 6405 89639693 500 2520 2227 1811 9330 1928 5140 4030 4824 806 31341652 8171 14353366 6543 37459286 8509 46457397 5790 89726597 4422 17999276 4041 38478683 7378 49465348 1993 91866724 9015 56464502 4439 84745107 7342 94421387 8910 2660

2. A method according to claim 1, further comprising:

modulating the LDPC coded signal; and

transmitting the modulated signal.

3. A method according to claim 2, wherein the modulated signal is transmitted over a satellite link in support of a broadband satellite application.

4. A method according to claim 2, wherein the modulating step is performed according to a signal constellation that includes one of 8-PSK (Phase Shift Keying), 16-QAM (Quadrature Amplitude Modulation), QPSK (Quadrature Phase Shift Keying), 16-APSK (Amplitude Phase Shift Keying) or 32-APSK.

5. A computer-readable medium bearing instructions for encoding, said instruction, being arranged, upon execution, to cause one or more processors to perform the method of claim 1.

6. An encoder comprising:

means for receiving information bits; and

means for generating, based on the information bits, a Low Density Parity Check (LDPC) code having an outer Bose Chaudhuri Hocquenghem (BCH) code for transmission as the LDPC coded signal according to one of a plurality of code rates associated with respective tables each specifying address of parity bit accumulators,

Address of Parity Bit Accumulators (Rate ⅓

)34903 20927 32093 1052 25611 16093 16454 5520 506 37399 1851821120 11636 14594 22158 14763 15333 6838 22222 37856 14985 3104118704 32910 17449 1665 35639 16624 12867 12449 10241 11650 2562234372 19878 26894 29235 19780 36056 20129 20029 5457 8157 3555421237 7943 13873 14980 9912 7143 35911 12043 17360 37253 2558811827 29152 21936 24125 40870 40701 36035 39556 12366 19946 2907216365 35495 22686 11106 8756 34863 19165 15702 13536 40238 446540034 40590 37540 17162 1712 20577 14138 31338 19342 9301 393753211 1316 33409 28670 12282 6118 29236 35787 11504 30506 195585100 24188 24738 30397 33775 9699 6215 3397 37451 34689 231267571 1058 12127 27518 23064 11265 14867 30451 28289 2966 1166015334 16867 15160 38343 3778 4265 39139 17293 26229 42604 1348631497 1365 14828 7453 26350 41346 28643 23421 8354 16255 1105524279 15687 12467 13906 5215 41328 23755 20800 6447 7970 280333262 39843 5363 22469 38091 28457 36696 34471 23619 2404 2422941754 1297 18563 3673 39070 14480 30279 37483 7580 29519 3051939831 20252 18132 20010 34386 7252 27526 12950 6875 43020 3156639069 18985 15541 40020 16715 1721 37332 39953 17430 32134 2916210490 12971 28581 29331 6489 35383 736 7022 42349 8783 6767 1187121675 10325 11548 25978 431 24085 1925 10602 28585 12170 1515634404 8351 13273 20208 5800 15367 21764 16279 37832 34792 2125034192 7406 41488 18346 29227 26127 25493 704839948 28229 2489917408 14274 3899338774 15968 2845941404 27249 2742541229 6082 4311413957 4979 406543093 3438 3499234082 6172 2876042210 34141 4102114705 17783 1013441755 39884 2277314615 15593 164229111 37061 398609579 33552 63312951 21137 3960838244 27361 294172939 10172 3647929094 5357 192249562 24436 2863740177 2326 135046834 21583 4251640651 42810 2570931557 32138 3814218624 41867 3929637560 14295 162456821 21679 3157025339 25083 220818047 697 352689884 17073 1999526848 35245 839018658 16134 1480712201 32944 503525236 1216 3898642994 24782 868128321 4932 342494107 29382 3212422157 2624 1446838788 27081 79364368 26148 1057825353 4122 39751Address of Parity Bit Accumulators (Rate ¼

)23606 36098 1140 28859 18148 18510 6226 540 42014 20879 2380247088 16419 24928 16609 17248 7693 24997 42587 16858 34921 2104237024 20692 1874 40094 18704 14474 14004 11519 13106 28826 3866922363 30255 31105 22254 40564 22645 22532 6134 9176 39998 238928937 15608 16854 31009 8037 40401 13550 19526 41902 28782 1330432796 24679 27140 45980 10021 40540 44498 13911 22435 32701 1840539929 25521 12497 9851 39223 34823 15233 45333 5041 44979 4571042150 19416 1892 23121 15860 8832 10308 10468 44296 3611 148037581 32254 13817 6883 32892 40258 46538 11940 6705 21634 2815043757 895 6547 20970 28914 30117 25736 41734 11392 22002 573927210 27828 34192 37992 10915 6998 3824 42130 4494 35739 85151191 13642 30950 25943 12673 16726 34261 31828 3340 8747 3922518979 17058 43130 4246 4793 44030 19454 29511 47929 15174 2433319354 16694 8381 29642 46516 32224 26344 9405 18292 12437 2731635466 41992 15642 5871 46489 26723 23396 7257 8974 3156 3742044823 35423 13541 42858 32008 41282 38773 26570 2702 27260 469741469 20887 27426 3855322152 24261 829719347 9978 2780234991 6354 3356129782 30875 295239278 48512 1434938061 4165 438788548 33172 3441022535 28811 2395020439 4027 2418638618 8187 3094735538 43880 214597091 45616 150635505 9315 2190836046 32914 118367304 39782 3372116905 29962 1298011171 23709 2246034541 9937 4450014035 47316 881515057 45482 2446130518 36877 8797583 13364 24332448 27056 468212083 31378 216701159 18031 222117028 38715 935017343 24530 2957446128 31039 3281820373 36967 1834546685 20622 32806Address of Parity Bit Accumulators (Rate ⅖

)5650 4143 8750 583 6720 8071 635 1767 1344 6922 738 66585696 1685 3207 415 7019 5023 5608 2605 857 6915 1770 80163992 771 2190 7258 8970 7792 1802 1866 6137 8841 886 19314108 3781 7577 6810 9322 8226 5396 5867 4428 8827 7766 22544247 888 4367 8821 9660 324 5864 4774 227 7889 6405 89639693 500 2520 2227 1811 9330 1928 5140 4030 4824 806 31341652 8171 14353366 6543 37459286 8509 46457397 5790 89726597 4422 17999276 4041 38478683 7378 49465348 1993 91866724 9015 56464502 4439 84745107 7342 94421387 8910 2660

7. An encoder according to claim 6, wherein the LDPC coded signal is modulated and transmitted over a satellite link.

8. An encoder according to claim 7, wherein the modulated signal is in support of a broadband satellite application.

9. An encoder according to claim 7, wherein the modulation is performed according to a signal constellation that includes one of 8-PSK (Phase Shift Keying), 16-QAM (Quadrature Amplitude Modulation), QPSK (Quadrature Phase Shift Keying), 16-APSK (Amplitude Phase Shift Keying) or 32-APSK.

10. A transmitter for supporting transmission of a Low Density Parity Check (LDPC) coded signal, comprising:

a Low Density Parity Check (LDPC) encoder configured to output, based on received information bits, an LDPC code; and

a Bose Chaudhuri Hocquenghem (BCH) encoder coupled to the LDPC encoder and configured to provide an outer code to the LDPC code, wherein the LDPC code is generated according to one of a code rate of ⅓

, a code rate of ¼

, or a code rate of ⅖

associated with respective tables each specifying address of parity bit accumulators,

Address of Parity Bit Accumulators (Rate ⅓

)34903 20927 32093 1052 25611 16093 16454 5520 506 37399 1851821120 11636 14594 22158 14763 15333 6838 22222 37856 14985 3104118704 32910 17449 1665 35639 16624 12867 12449 10241 11650 2562234372 19878 26894 29235 19780 36056 20129 20029 5457 8157 3555421237 7943 13873 14980 9912 7143 35911 12043 17360 37253 2558811827 29152 21936 24125 40870 40701 36035 39556 12366 19946 2907216365 35495 22686 11106 8756 34863 19165 15702 13536 40238 446540034 40590 37540 17162 1712 20577 14138 31338 19342 9301 393753211 1316 33409 28670 12282 6118 29236 35787 11504 30506 195585100 24188 24738 30397 33775 9699 6215 3397 37451 34689 231267571 1058 12127 27518 23064 11265 14867 30451 28289 2966 1166015334 16867 15160 38343 3778 4265 39139 17293 26229 42604 1348631497 1365 14828 7453 26350 41346 28643 23421 8354 16255 1105524279 15687 12467 13906 5215 41328 23755 20800 6447 7970 280333262 39843 5363 22469 38091 28457 36696 34471 23619 2404 2422941754 1297 18563 3673 39070 14480 30279 37483 7580 29519 3051939831 20252 18132 20010 34386 7252 27526 12950 6875 43020 3156639069 18985 15541 40020 16715 1721 37332 39953 17430 32134 2916210490 12971 28581 29331 6489 35383 736 7022 42349 8783 6767 1187121675 10325 11548 25978 431 24085 1925 10602 28585 12170 1515634404 8351 13273 20208 5800 15367 21764 16279 37832 34792 2125034192 7406 41488 18346 29227 26127 25493 704839948 28229 2489917408 14274 3899338774 15968 2845941404 27249 2742541229 6082 4311413957 4979 406543093 3438 3499234082 6172 2876042210 34141 4102114705 17783 1013441755 39884 2277314615 15593 164229111 37061 398609579 33552 63312951 21137 3960838244 27361 294172939 10172 3647929094 5357 192249562 24436 2863740177 2326 135046834 21583 4251640651 42810 2570931557 32138 3814218624 41867 3929637560 14295 162456821 21679 3157025339 25083 220818047 697 352689884 17073 1999526848 35245 839018658 16134 1480712201 32944 503525236 1216 3898642994 24782 868128321 4932 342494107 29382 3212422157 2624 1446838788 27081 79364368 26148 1057825353 4122 39751Address of Parity Bit Accumulators (Rate ¼

)23606 36098 1140 28859 18148 18510 6226 540 42014 20879 2380247088 16419 24928 16609 17248 7693 24997 42587 16858 34921 2104237024 20692 1874 40094 18704 14474 14004 11519 13106 28826 3866922363 30255 31105 22254 40564 22645 22532 6134 9176 39998 238928937 15608 16854 31009 8037 40401 13550 19526 41902 28782 1330432796 24679 27140 45980 10021 40540 44498 13911 22435 32701 1840539929 25521 12497 9851 39223 34823 15233 45333 5041 44979 4571042150 19416 1892 23121 15860 8832 10308 10468 44296 3611 148037581 32254 13817 6883 32892 40258 46538 11940 6705 21634 2815043757 895 6547 20970 28914 30117 25736 41734 11392 22002 573927210 27828 34192 37992 10915 6998 3824 42130 4494 35739 85151191 13642 30950 25943 12673 16726 34261 31828 3340 8747 3922518979 17058 43130 4246 4793 44030 19454 29511 47929 15174 2433319354 16694 8381 29642 46516 32224 26344 9405 18292 12437 2731635466 41992 15642 5871 46489 26723 23396 7257 8974 3156 3742044823 35423 13541 42858 32008 41282 38773 26570 2702 27260 469741469 20887 27426 3855322152 24261 829719347 9978 2780234991 6354 3356129782 30875 295239278 48512 1434938061 4165 438788548 33172 3441022535 28811 2395020439 4027 2418638618 8187 3094735538 43880 214597091 45616 150635505 9315 2190836046 32914 118367304 39782 3372116905 29962 1298011171 23709 2246034541 9937 4450014035 47316 881515057 45482 2446130518 36877 8797583 13364 24332448 27056 468212083 31378 216701159 18031 222117028 38715 935017343 24530 2957446128 31039 3281820373 36967 1834546685 20622 32806Address of Parity Bit Accumulators (Rate ⅖

)5650 4143 8750 583 6720 8071 635 1767 1344 6922 738 66585696 1685 3207 415 7019 5023 5608 2605 857 6915 1770 80163992 771 2190 7258 8970 7792 1802 1866 6137 8841 886 19314108 3781 7577 6810 9322 8226 5396 5867 4428 8827 7766 22544247 888 4367 8821 9660 324 5864 4774 227 7889 6405 89639693 500 2520 2227 1811 9330 1928 5140 4030 4824 806 31341652 8171 14353366 6543 37459286 8509 46457397 5790 89726597 4422 17999276 4041 38478683 7378 49465348 1993 91866724 9015 56464502 4439 84745107 7342 94421387 8910 2660

11. A transmitter according to claim 10, further comprising:

a modulator configured to modulate the LDPC coded signal.

12. A transmitter according to claim 11, wherein the modulated signal is transmitted over a satellite link in support of a broadband satellite application.

13. A transmitter according to claim 11, wherein the modulation is performed according to a signal constellation that includes one of 8-PSK (Phase Shift Keying), 16-QAM (Quadrature Amplitude Modulation), QPSK (Quadrature Phase Shift Keying), 16-APSK (Amplitude Phase Shift Keying) or 32-APSK.

14. (canceled)