Downstream FEC Proposal for EPoC

23rd January 2013

2

SupportersJorge Salinger Comcast

Rajeev Jain Qualcomm

Steve Shellhammer Qualcomm

Juan Montojo Qualcomm

Sanjay Kasturia Qualcomm

Alex Liu Qualcomm

Dylan Ko Qualcomm

Christian Pietsch Qualcomm

Nicola Varanese Qualcomm

Andrea Garavaglia Qualcomm

Mike Emmendorfer Arris

Boris Brun Harmonicinc

Charaf Hannah ST Microelectronics

Bill Powell Alcatel-Lucent

Venkat Arunarthi Cortina Systems

Tim Brophy Cisco

Robert Howald Motorola Mobility

Tom Staniec Cohere

3

• DVB-C2 Bit interleaved coded modulation (BICM)

• 16200-length shorter LDPC code + BCH outer code

• Column twisted Bit interleaver.

• This is mature and has been proven to work in HFC environment

• We propose to use code rate 8/9 as the primary code rate for all SNR

• We support all square constellations from QAM16 to QAM4096

• We extend DVB-C2 to non-square or odd constellations (128/512/2048)

• We define column-twisted bit interleavers for non-square constellations

• We combine successive modulations with a fixed 50:50 ratio to get 1.5 dB SNR step size in the spectral efficiency graph, using 8/9 code rate only (this will be explained in detail)

• We propose to include code rates 7/9 and 6/9 with minimal extra complexity for extreme burst conditions

FEC Proposal for EPOC Downstream

4

• DVB-C2 supports square QAM constellations only, but has six LDPC code rates

• Even with all these rates, some operating points are separated by about 3 dB along the SNR axis of the spectral efficiency graph. Also the operating points are not uniformly spaced.

• It is preferable to achieve a SNR point using a lower order modulation and higher code rate than higher order modulation and lower code rate

• Because of losses (e.g. phase noise) in the demodulator

• Furthermore, higher code rates are more hardware efficient than lower code rates because of fewer number of parity check equations

• Hence our aim has been to use only the highest code rate of 8/9

• To achieve a 3 dB SNR resolution in the spectral efficiency graph with 8/9 code rate we have defined non-square constellations & associated column-twisted bit interleavers

• Then we go up and down the spectral efficiency graph in 3 dB steps by changing only the modulation, keeping code rate fixed

• See later for the way of achieving 1.5 dB SNR step

Extension to Non-Square Constellations

5

• Back-up material of this presentation contains:

• Details of column twisted bit interleavers for QAM128/512/2048

• Details of constellation mappings

• Modifications to the tables of the DVB-C2 specification to include odd or non-square constellations

Detailed Specification of Odd or Non-square QAM Constellations

Idea for Achieving 1.5 dB SNR Resolution

• In each OFDM symbol

• We make 50% of the data carriers square-QAM, say QAM4096

• We make other 50% of data carriers non-square-QAM, say QAM2048

Frequency

QAM4096

QAM2048

LLRGenerator

16200-bit LDPCDecoder

(with outer BCH)

• So the spectral efficiency of the new modulation is halfway between QAM4096 and QAM2048

• We show that the SNR requirement is also halfway between the SNR requirements of QAM4096 and QAM2048

• Same applies to QAM-1024/2048, 512/1024, 256/512 & 128/256

Combined Modulation Definition

• The only purpose of the combined modulation idea is to achieve approximate 1.5 dB SNR resolution in the spectral efficiency graph

• For example, to get the mid-point between QAM2048 and QAM4096 we combine these modulations 50:50 within one LDPC codeword

• LDPC-coded bits to OFDM carrier mapping has a fixed pattern and ratio:

• QAM2N+1 carriers occupy locations 0, 2, 4, …

• QAM2N carriers occupy locations 1, 3, 5, …

• This bits to carrier mapping happens after LDPC encoding and bit interleaving but before time and frequency interleaving

• This fixed mapping is signalled by the same parameter that is used to signal the QAM constellation. It is an “effective constellation” halfway between QAM2N+1 and QAM2N

• Note also that a LDPC codeword always maps onto an integer number of OFDM sub-carriers. This means that in some instances there could be unused bits in the last sub-carrier, that are discarded by receiver.

• For combined modulation we use the bit interleaver defined for QAM4096

AWGN Performance

1.00E-10

1.00E-09

1.00E-08

1.00E-07

1.00E-06

1.00E-05

1.00E-04

1.00E-03

20 22 24 26 28 30 32 34 36 38

SNR (dB)

CODE RATE 8/9

QAM4096

QAM2048/4096

QAM2048

QAM1024/2048

QAM1024

QAM512/1024

QAM512

QAM256/512

QAM256

QAM128

15 iterations

• Shows square and non-square constellations, as well as those in between

• The performance has been measured by limiting iteration count to 15

Spectral Efficiency Graph

8/9

8/9

8/9

8/9

8/9

8/9

8/9

8/9

8/9

8/96

7

8

9

10

11

12

20 22 24 26 28 30 32 34 36

Sp

ect

ral

Eff

icie

ncy

(b

its/

s/H

z)

SNR (dB)

Code Rate 8/9

Capacity

QAM4096

QAM2048/4096

QAM2048

QAM1024/2048

QAM1024

QAM512/1024

QAM512

QAM 256/512

QAM256

QAM128

15 iterations

• All results obtained using the simplest LDPC code rate of 8/9

• Operating points are more uniformly spaced than in the DVB-C2 standard which uses six code rates

Burst Performance

• We propose using a convolutional time interleaver operating on OFDM sub-carriers to mitigate broadband burst noise

• Different sub-carriers of each OFDM symbol delayed by different amounts

• Burst errors in the channel can impact one (or even two) OFDM symbols

• Convolutional de-interleaver will spread this burst over M symbols

• M is the depth of the interleaver in OFDM symbols

• Value of M limited by the tolerable latency and memory size

• We propose making the interleaver depth programmable with a maximum value of 32

• Use of convolutional sub-carrier-level interleaving gives the most memory efficient hardware architecture

Time Interleaver Structure

J

2J

3J

(M-1)J

Burst noise

M

Time

Freq.

Burst noise distributed over M symbols

Interleaver depth = M symbolsLatency = M symbols

Time Interleaver Parameter J

J

2J

3J

(M-1)J

Interleaver depth = M symbolsLatency = M symbols

• Let N be the number of data carriers in the OFDM symbol. N may not be a multiple of M

• Define J = (N/M)

• But (N/M) may be a fraction. Then J is the next highest integer

• Append (JM – N) dummy carriers to make the symbol length a multiple of M

• Enter the dummy carriers into the interleaver, but discard at interleaver output

• But during implementation dummy carriers not written or read

13

Burst Noise Performance Simulations

Burst Condition Interleaver depth

+20 dB SNR burst of 16 us impacting Two symbols 10-12 symbols with code rate 8/9

-inf SNR burst of erasing One complete symbol 12 symbols with code rate 8/9

-inf SNR burst of erasing Two complete symbols 26 symbols with code rate 8/9

-inf SNR burst of erasing Two complete symbols 18 symbols with code rate 7/9

-inf SNR burst of erasing Two complete symbols 8 symbols with code rate 6/9

• Hence we propose including code rates 7/9 and 6/9 code rates as back-up for low latency applications operating in extreme burst noise conditions

14

• We propose DVB-C2 FEC with

• 16200-length LDPC code + BCH outer code

• Column twisted Bit interleaver.

• We propose to use code rate 8/9 as the primary code rate for all SNR

• Support all square (even) QAM constellations from QAM16 to QAM4096

• Extended to non-square (odd) QAM constellations QAM128, 512 and 2048

• With column-twisted bit interleavers defined for non-square constellations

• We propose combining successive modulations with fixed 50:50 ratio and fixed odd-even locations within an FEC codeword to achieve 1.5 dB resolution along the SNR axis of the spectral efficiency graph

• We propose to include code rates 7/9 and 6/9 with minimal extra complexity for extreme burst conditions

Conclusions

Proposed Motion

• Propose that the DVB-C2 Forward Error Correction scheme, with the following modifications, be adopted as the downstream Forward Error Correction Scheme of EPOC

• Use a single primary code rate of 8/9 to cover all SNR conditions

• Use back-up rates 7/9 and 6/9 for extreme burst noise conditions

• Include odd order QAM constellations with associated column-twisted bit interleavers

• Provide an option to map carriers with successive QAM constellations onto one LDPC codeword, via the bit interleaver defined for QAM4096, but with fixed 50:50 ratio and fixed odd-even locations

� Moved by: � Seconded by: � Technical motion (>=75%) � Yes / No / Abstain

THANK YOU!

16

17

ETSI EN 302 769 V1.2.1 (2011-04) Digital Video Broadcasting (DVB); Frame structure channel coding and modulation for a second generation digital transmission system for cable systems (DVB-C2)

The following pages contain changes to the DVB-C2 specification to incorporate non-square constellations 128, 512 and 1024

Details of Specification

18

Column-twisted Bit Interleaver for Non-Square QAM

Since 16,200 is not divisible by 7 and 11, for QAM-128 and QAM-2048 constellations, zeros shall be appended after parity interleaving and prior to column-twist interleaving at the end of the block (5 zero bits for QAM-128 and 3 zero bits for QAM-2048 added after the 16,200th bit), thus the extended block of 16,205 bits or 16,203 bits shall be interleaved by the column-twist interleaver for QAM-128 and QAM-2048 respectively.

The following rows are added to table 6 of DVB-C2 specification.

ModulationRows Nr Columns

NcNldpc = 64 800 Nldpc = 16 200

128QAM - 2 315 7

512QAM - 1 800 9

2048QAM - 1 473 11

The following rows are added to table 7(a) of DVB-C2 specification.

ModulationColumns

Nldpc

Twisting parameter tc

Nc Col. 0 1 2 3 4 5 6 7 8 9 10 11

128QAM

7 16200 0 1 2 2 2 3 3 - - - - -

512 QAM 9 16200 0 1 2 3 5 6 7 9 11 - - -

2048 QAM 11 16200 0 0 0 0 0 3 3 4 4 4 4 -

19

Constellation Mappings for Non-Square QAM

-11 -9 -7 -5 -3 -1 1 3 5 7 9 11

-11

-9

-7

-5

-3

-1

1

3

5

7

9

11

01

23

4 5

6 7

8 9

10 11

12 13

14 15

16 17

18 19

2021

2223

24 25

26 27

2829

3031

3233

3435

36 37

38 39

40 41

42 43

44 45

46 47

48 49

50 51

5253

5455

56 57

58 59

6061

6263

64 65

66 67

6869

7071

7273

7475

7677

7879

8081

8283

84 85

86 87

8889

9091

92 93

94 95

96 97

98 99

100101

102103

104105

106107

108109

110111

112113

114115

116 117

118 119

120121

122123

124 125

126 127

The mapping is given in decimal number format and the symbols are arranged on an odd integer grid.

QAM128

20

QAM512

-23 -21 -19 -17 -15 -13 -11 -9 -7 -5 -3 -1 1 3 5 7 9 11 13 15 17 19 21 23

-23

-21

-19

-17

-15

-13

-11

-9

-7

-5

-3

-1

1

3

5

7

9

11

13

15

17

19

21

23

01

23

4 5

6 7

89

1011

12 13

14 15

16 17

18 19

2021

2223

24 25

26 27

2829

3031

32 33

34 35

3637

3839

40 41

42 43

4445

4647

48 49

50 51

5253

5455

56 57

58 59

6061

6263

64 65

66 67

6869

7071

72 73

74 75

7677

7879

8081

8283

84 85

86 87

8889

9091

92 93

94 95

96 97

98 99

100101

102103

104 105

106 107

108109

110111

112113

114115

116 117

118 119

120121

122123

124 125

126 127

128129

130131

132 133

134 135

136137

138139

140 141

142 143

144 145

146 147

148149

150151

152 153

154 155

156157

158159

160 161

162 163

164165

166167

168 169

170 171

172173

174175

176 177

178 179

180181

182183

184 185

186 187

188189

190191

192 193

194 195

196197

198199

200 201

202 203

204205

206207

208209

210211

212 213

214 215

216217

218219

220 221

222 223

224 225

226 227

228229

230231

232 233

234 235

236237

238239

240241

242243

244 245

246 247

248249

250251

252 253

254 255

256 257

258 259

260261

262263

264 265

266 267

268269

270271

272273

274275

276 277

278 279

280281

282283

284 285

286 287

288289

290291

292 293

294 295

296297

298299

300 301

302 303

304305

306307

308 309

310 311

312313

314315

316 317

318 319

320321

322323

324 325

326 327

328329

330331

332 333

334 335

336 337

338 339

340341

342343

344 345

346 347

348349

350351

352353

354355

356 357

358 359

360361

362363

364 365

366 367

368 369

370 371

372373

374375

376 377

378 379

380381

382383

384 385

386 387

388389

390391

392 393

394 395

396397

398399

400401

402403

404 405

406 407

408409

410411

412 413

414 415

416417

418419

420 421

422 423

424425

426427

428 429

430 431

432433

434435

436 437

438 439

440441

442443

444 445

446 447

448449

450451

452 453

454 455

456457

458459

460 461

462 463

464 465

466 467

468469

470471

472 473

474 475

476477

478479

480481

482483

484 485

486 487

488489

490491

492 493

494 495

496 497

498 499

500501

502503

504 505

506 507

508509

510511

21

QAM2048 Quadrant 1

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

13579

11131517192123252729313335373941434547

01

23

4 5

6 7

89

1011

12 13

14 15

16 17

18 19

2021

2223

24 25

26 27

2829

3031

3233

3435

36 37

38 39

4041

4243

44 45

46 47

48 49

50 51

5253

5455

56 57

58 59

6061

6263

64 65

66 67

6869

7071

72 73

74 75

7677

7879

8081

8283

84 85

86 87

8889

9091

92 93

94 95

96 97

98 99

100101

102103

104 105

106 107

108109

110111

112113

114115

116 117

118 119

120121

122123

124 125

126 127

128 129

130 131

132133

134135

136 137

138 139

140141

142143

144145

146147

148 149

150 151

152153

154155

156 157

158 159

160 161

162 163

164165

166167

168 169

170 171

172173

174175

176177

178179

180 181

182 183

184185

186187

188 189

190 191

192 193

194 195

196197

198199

200 201

202 203

204205

206207

208209

210211

212 213

214 215

216217

218219

220 221

222 223

224 225

226 227

228229

230231

232 233

234 235

236237

238239

240241

242243

244 245

246 247

248249

250251

252 253

254 255

256 257

258 259

260261

262263

264 265

266 267

268269

270271

272273

274275

276 277

278 279

280281

282283

284 285

286 287

288 289

290 291

292293

294295

296 297

298 299

300301

302303

304305

306307

308 309

310 311

312313

314315

316 317

318 319

320321

322323

324 325

326 327

328329

330331

332 333

334 335

336 337

338 339

340341

342343

344 345

346 347

348349

350351

352353

354355

356 357

358 359

360361

362363

364 365

366 367

368 369

370 371

372373

374375

376 377

378 379

380381

382383

384 385

386 387

388389

390391

392 393

394 395

396397

398399

400401

402403

404 405

406 407

408409

410411

412 413

414 415

416 417

418 419

420421

422423

424 425

426 427

428429

430431

432433

434435

436 437

438 439

440441

442443

444 445

446 447

448449

450451

452 453

454 455

456457

458459

460 461

462 463

464 465

466 467

468469

470471

472 473

474 475

476477

478479

480481

482483

484 485

486 487

488489

490491

492 493

494 495

496 497

498 499

500501

502503

504 505

506 507

508509

510511

22

QAM2048 Quadrant 2

-47 -45 -43 -41 -39 -37 -35 -33 -31 -29 -27 -25 -23 -21 -19 -17 -15 -13 -11 -9 -7 -5 -3 -1

13579

11131517192123252729313335373941434547

1024 1025

1026 1027

10281029

10301031

1032 1033

1034 1035

10361037

10381039

10401041

10421043

1044 1045

1046 1047

10481049

10501051

1052 1053

1054 1055

1056 1057

1058 1059

10601061

10621063

1064 1065

1066 1067

10681069

10701071

10721073

10741075

1076 1077

1078 1079

10801081

10821083

1084 1085

1086 1087

10881089

10901091

1092 1093

1094 1095

10961097

10981099

1100 1101

1102 1103

1104 1105

1106 1107

11081109

11101111

1112 1113

1114 1115

11161117

11181119

11201121

11221123

1124 1125

1126 1127

11281129

11301131

1132 1133

1134 1135

1136 1137

1138 1139

11401141

11421143

1144 1145

1146 1147

11481149

11501151

11521153

11541155

1156 1157

1158 1159

11601161

11621163

1164 1165

1166 1167

1168 1169

1170 1171

11721173

11741175

1176 1177

1178 1179

11801181

11821183

11841185

11861187

1188 1189

1190 1191

11921193

11941195

1196 1197

1198 1199

1200 1201

1202 1203

12041205

12061207

1208 1209

1210 1211

12121213

12141215

12161217

12181219

1220 1221

1222 1223

12241225

12261227

1228 1229

1230 1231

1232 1233

1234 1235

12361237

12381239

1240 1241

1242 1243

12441245

12461247

12481249

12501251

1252 1253

1254 1255

12561257

12581259

1260 1261

1262 1263

1264 1265

1266 1267

12681269

12701271

1272 1273

1274 1275

12761277

12781279

12801281

12821283

1284 1285

1286 1287

12881289

12901291

1292 1293

1294 1295

1296 1297

1298 1299

13001301

13021303

1304 1305

1306 1307

13081309

13101311

13121313

13141315

1316 1317

1318 1319

13201321

13221323

1324 1325

1326 1327

1328 1329

1330 1331

13321333

13341335

1336 1337

1338 1339

13401341

13421343

1344 1345

1346 1347

13481349

13501351

1352 1353

1354 1355

13561357

13581359

13601361

13621363

1364 1365

1366 1367

13681369

13701371

1372 1373

1374 1375

1376 1377

1378 1379

13801381

13821383

1384 1385

1386 1387

13881389

13901391

13921393

13941395

1396 1397

1398 1399

14001401

14021403

1404 1405

1406 1407

14081409

14101411

1412 1413

1414 1415

14161417

14181419

1420 1421

1422 1423

1424 1425

1426 1427

14281429

14301431

1432 1433

1434 1435

14361437

14381439

14401441

14421443

1444 1445

1446 1447

14481449

14501451

1452 1453

1454 1455

1456 1457

1458 1459

14601461

14621463

1464 1465

1466 1467

14681469

14701471

1472 1473

1474 1475

14761477

14781479

1480 1481

1482 1483

14841485

14861487

14881489

14901491

1492 1493

1494 1495

14961497

14981499

1500 1501

1502 1503

1504 1505

1506 1507

15081509

15101511

1512 1513

1514 1515

15161517

15181519

15201521

15221523

1524 1525

1526 1527

15281529

15301531

1532 1533

1534 1535

23

QAM2048 Quadrant 3

-47 -45 -43 -41 -39 -37 -35 -33 -31 -29 -27 -25 -23 -21 -19 -17 -15 -13 -11 -9 -7 -5 -3 -1

-47

-45

-43

-41

-39

-37

-35

-33

-31

-29

-27

-25

-23

-21

-19

-17

-15

-13

-11

-9

-7

-5

-3

-1

1536 1537

1538 1539

15401541

15421543

1544 1545

1546 1547

15481549

15501551

15521553

15541555

1556 1557

1558 1559

15601561

15621563

1564 1565

1566 1567

1568 1569

1570 1571

15721573

15741575

1576 1577

1578 1579

15801581

15821583

15841585

15861587

1588 1589

1590 1591

15921593

15941595

1596 1597

1598 1599

16001601

16021603

1604 1605

1606 1607

16081609

16101611

1612 1613

1614 1615

1616 1617

1618 1619

16201621

16221623

1624 1625

1626 1627

16281629

16301631

16321633

16341635

1636 1637

1638 1639

16401641

16421643

1644 1645

1646 1647

1648 1649

1650 1651

16521653

16541655

1656 1657

1658 1659

16601661

16621663

16641665

16661667

1668 1669

1670 1671

16721673

16741675

1676 1677

1678 1679

1680 1681

1682 1683

16841685

16861687

1688 1689

1690 1691

16921693

16941695

16961697

16981699

1700 1701

1702 1703

17041705

17061707

1708 1709

1710 1711

1712 1713

1714 1715

17161717

17181719

1720 1721

1722 1723

17241725

17261727

17281729

17301731

1732 1733

1734 1735

17361737

17381739

1740 1741

1742 1743

1744 1745

1746 1747

17481749

17501751

1752 1753

1754 1755

17561757

17581759

17601761

17621763

1764 1765

1766 1767

17681769

17701771

1772 1773

1774 1775

1776 1777

1778 1779

17801781

17821783

1784 1785

1786 1787

17881789

17901791

17921793

17941795

1796 1797

1798 1799

18001801

18021803

1804 1805

1806 1807

1808 1809

1810 1811

18121813

18141815

1816 1817

1818 1819

18201821

18221823

18241825

18261827

1828 1829

1830 1831

18321833

18341835

1836 1837

1838 1839

1840 1841

1842 1843

18441845

18461847

1848 1849

1850 1851

18521853

18541855

1856 1857

1858 1859

18601861

18621863

1864 1865

1866 1867

18681869

18701871

18721873

18741875

1876 1877

1878 1879

18801881

18821883

1884 1885

1886 1887

1888 1889

1890 1891

18921893

18941895

1896 1897

1898 1899

19001901

19021903

19041905

19061907

1908 1909

1910 1911

19121913

19141915

1916 1917

1918 1919

19201921

19221923

1924 1925

1926 1927

19281929

19301931

1932 1933

1934 1935

1936 1937

1938 1939

19401941

19421943

1944 1945

1946 1947

19481949

19501951

19521953

19541955

1956 1957

1958 1959

19601961

19621963

1964 1965

1966 1967

1968 1969

1970 1971

19721973

19741975

1976 1977

1978 1979

19801981

19821983

1984 1985

1986 1987

19881989

19901991

1992 1993

1994 1995

19961997

19981999

20002001

20022003

2004 2005

2006 2007

20082009

20102011

2012 2013

2014 2015

2016 2017

2018 2019

20202021

20222023

2024 2025

2026 2027

20282029

20302031

20322033

20342035

2036 2037

2038 2039

20402041

20422043

2044 2045

2046 2047

24

QAM2048 Quadrant 4

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

-47-45-43-41-39-37-35-33-31-29-27-25-23-21-19-17-15-13-11

-9-7-5-3-1

512513

514515

516 517

518 519

520521

522523

524 525

526 527

528 529

530 531

532533

534535

536 537

538 539

540541

542543

544545

546547

548 549

550 551

552553

554555

556 557

558 559

560 561

562 563

564565

566567

568 569

570 571

572573

574575

576 577

578 579

580581

582583

584 585

586 587

588589

590591

592593

594595

596 597

598 599

600601

602603

604 605

606 607

608 609

610 611

612613

614615

616 617

618 619

620621

622623

624625

626627

628 629

630 631

632633

634635

636 637

638 639

640 641

642 643

644645

646647

648 649

650 651

652653

654655

656657

658659

660 661

662 663

664665

666667

668 669

670 671

672 673

674 675

676677

678679

680 681

682 683

684685

686687

688689

690691

692 693

694 695

696697

698699

700 701

702 703

704 705

706 707

708709

710711

712 713

714 715

716717

718719

720721

722723

724 725

726 727

728729

730731

732 733

734 735

736 737

738 739

740741

742743

744 745

746 747

748749

750751

752753

754755

756 757

758 759

760761

762763

764 765

766 767

768 769

770 771

772773

774775

776 777

778 779

780781

782783

784785

786787

788 789

790 791

792793

794795

796 797

798 799

800 801

802 803

804805

806807

808 809

810 811

812813

814815

816817

818819

820 821

822 823

824825

826827

828 829

830 831

832833

834835

836 837

838 839

840841

842843

844 845

846 847

848 849

850 851

852853

854855

856 857

858 859

860861

862863

864865

866867

868 869

870 871

872873

874875

876 877

878 879

880 881

882 883

884885

886887

888 889

890 891

892893

894895

896 897

898 899

900901

902903

904 905

906 907

908909

910911

912913

914915

916 917

918 919

920921

922923

924 925

926 927

928 929

930 931

932933

934935

936 937

938 939

940941

942943

944945

946947

948 949

950 951

952953

954955

956 957

958 959

960961

962963

964 965

966 967

968969

970971

972 973

974 975

976 977

978 979

980981

982983

984 985

986 987

988989

990991

992993

994995

996 997

998 999

10001001

10021003

10041005

10061007

10081009

10101011

10121013

10141015

10161017

10181019

10201021

10221023

25

The following rows are added to table 8 of DVB-C2 specification.

LDPC block length (NLDPC) Modulation mode ηηηηMODNumber of output Data

Cells

16 200

128QAM 7 2 315

512QAM 9 1 800

2048QAM 11 1 473

The following rows are added to table 9 of DVB-C2 specification.

Modulation NLDPC Number of sub-streams, Nsubstreams

128QAM 16200 7

512QAM 16200 9

2048QAM 16200 11

26

The following rows are added to table 10(a) and 10(b) of DVB-C2 specification.

Modulation format 128QAM (NLDPC = 16200) Input bit-number,

di mod Nsubstreams 0 1 2 3 4 5 6

Output bit-number, e 6 5 4 1 2 3 0

Modulation format 2048QAM (NLDPC = 16200) Input bit-number,

di mod Nsubstreams 0 1 2 3 4 5 6 7 8 9 10

Output bit-number, e 10 9 8 7 2 3 4 5 6 1 0

Modulation format 512QAM (NLDPC = 16200) Input bit-number,

di mod Nsubstreams 0 1 2 3 4 5 6 7 8

Output bit-number, e 8 7 6 1 2 3 4 5 0

27

The following rows are added to table 13 of DVB-C2 specification.

Modulation Normalization

128QAM 82q

q

zf =

512QAM 330

qq

zf =

2048QAM 1322

qq

zf =