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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
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
Recommended