3.12 Data channel for ECSD at full rate, 32.0 kbit/s radio interface rate (32.0 kbit/s services (E-TCH/F32.0))

3GPP45.003GSM/EDGE Channel codingRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

The definition of a 32.0 kbit/s radio interface rate data flow for data services is given in 3GPP TS 44.021.

3.12.1 Interface with user unit

The user unit delivers to the encoder a bit stream organized in blocks of 640 information bits (data frames) every 20 ms.

3.12.2 Void

3.12.3 Convolutional encoder

3.12.3.1 Tailing bits for a data frame

Before convolutional encoding 6 tail bits {d(k)=0, k=640,…,645} are added to the end of each data block.

3.12.3.2 Convolutional encoding for a data frame

This block of 646 bits {d(0),…,d(645)} is encoded with the 1/3 rate convolutional code (the same code as for MCS-1) defined by the following polynomials:

G4 = 1 + D2 + D3 + D5 + D6

G7 = 1 + D + D2 + D3 + D6

G5 = 1 + D + D⁴+ D⁶

resulting in 1938 coded bits {c(0), c(1),…, c(1937)} with

c(3k) = d(k) + d(k-2) + d(k-3) + d(k-5) + d(k-6) ;

c(3k+1) = d(k) + d(k-1) + d(k-2) + d(k-3) + d(k-6) ;

c(3k+2) = d(k) + d(k-1) + d(k-4) + d(k-6) ;

for k = 0,1,…,645 ; d(k) = 0 for k<1

The code is punctured using the rate matching algorithm of clause 6.2.3, such that the following 546 coded bits:

c(0), c(3), c(7), c(10), c(14), c(17), c(21), c(24), c(28), c(31), c(35), c(39), c(42), c(46), c(49), c(53), c(56), c(60), c(63), c(67), c(70), c(74), c(78), c(81), c(85), c(88), c(92), c(95), c(99), c(102), c(106), c(110), c(113), c(117), c(120), c(124), c(127), c(131), c(134), c(138), c(141), c(145), c(149), c(152), c(156), c(159), c(163), c(166), c(170), c(173), c(177), c(181), c(184), c(188), c(191), c(195), c(198), c(202), c(205), c(209), c(212), c(216), c(220), c(223), c(227), c(230), c(234), c(237), c(241), c(244), c(248), c(252), c(255), c(259), c(262), c(266), c(269), c(273), c(276), c(280), c(283), c(287), c(291), c(294), c(298), c(301), c(305), c(308), c(312), c(315), c(319), c(323), c(326), c(330), c(333), c(337), c(340), c(344), c(347), c(351), c(354), c(358), c(362), c(365), c(369), c(372), c(376), c(379), c(383), c(386), c(390), c(393), c(397), c(401), c(404), c(408), c(411), c(415), c(418), c(422), c(425), c(429), c(433), c(436), c(440), c(443), c(447), c(450), c(454), c(457), c(461), c(464), c(468), c(472), c(475), c(479), c(482), c(486), c(489), c(493), c(496), c(500), c(504), c(507), c(511), c(514), c(518), c(521), c(525), c(528), c(532), c(535), c(539), c(543), c(546), c(550), c(553), c(557), c(560), c(564), c(567), c(571), c(575), c(578), c(582), c(585), c(589), c(592), c(596), c(599), c(603), c(606), c(610), c(614), c(617), c(621), c(624), c(628), c(631), c(635), c(638), c(642), c(646), c(649), c(653), c(656), c(660), c(663), c(667), c(670), c(674), c(677), c(681), c(685), c(688), c(692), c(695), c(699), c(702), c(706), c(709), c(713), c(716), c(720), c(724), c(727), c(731), c(734), c(738), c(741), c(745), c(748), c(752), c(756), c(759), c(763), c(766), c(770), c(773), c(777), c(780), c(784), c(787), c(791), c(795), c(798), c(802), c(805), c(809), c(812), c(816), c(819), c(823), c(827), c(830), c(834), c(837), c(841), c(844), c(848), c(851), c(855), c(858), c(862), c(866), c(869), c(873), c(876), c(880), c(883), c(887), c(890), c(894), c(898), c(901), c(905), c(908), c(912), c(915), c(919), c(922), c(926), c(929), c(933), c(937), c(940), c(944), c(947), c(951), c(954), c(958), c(961), c(965), c(969), c(972), c(976), c(979), c(983), c(986), c(990), c(993), c(997), c(1000), c(1004), c(1008), c(1011), c(1015), c(1018), c(1022), c(1025), c(1029), c(1032), c(1036), c(1039), c(1043), c(1047), c(1050), c(1054), c(1057), c(1061), c(1064), c(1068), c(1071), c(1075), c(1079), c(1082), c(1086), c(1089), c(1093), c(1096), c(1100), c(1103), c(1107), c(1110), c(1114), c(1118), c(1121), c(1125), c(1128), c(1132), c(1135), c(1139), c(1142), c(1146), c(1150), c(1153), c(1157), c(1160), c(1164), c(1167), c(1171), c(1174), c(1178), c(1181), c(1185), c(1189), c(1192), c(1196), c(1199), c(1203), c(1206), c(1210), c(1213), c(1217), c(1221), c(1224), c(1228), c(1231), c(1235), c(1238), c(1242), c(1245), c(1249), c(1252), c(1256), c(1260), c(1263), c(1267), c(1270), c(1274), c(1277), c(1281), c(1284), c(1288), c(1292), c(1295), c(1299), c(1302), c(1306), c(1309), c(1313), c(1316), c(1320), c(1323), c(1327), c(1331), c(1334), c(1338), c(1341), c(1345), c(1348), c(1352), c(1355), c(1359), c(1362), c(1366), c(1370), c(1373), c(1377), c(1380), c(1384), c(1387), c(1391), c(1394), c(1398), c(1402), c(1405), c(1409), c(1412), c(1416), c(1419), c(1423), c(1426), c(1430), c(1433), c(1437), c(1441), c(1444), c(1448), c(1451), c(1455), c(1458), c(1462), c(1465), c(1469), c(1473), c(1476), c(1480), c(1483), c(1487), c(1490), c(1494), c(1497), c(1501), c(1504), c(1508), c(1512), c(1515), c(1519), c(1522), c(1526), c(1529), c(1533), c(1536), c(1540), c(1544), c(1547), c(1551), c(1554), c(1558), c(1561), c(1565), c(1568), c(1572), c(1575), c(1579), c(1583), c(1586), c(1590), c(1593), c(1597), c(1600), c(1604), c(1607), c(1611), c(1615), c(1618), c(1622), c(1625), c(1629), c(1632), c(1636), c(1639), c(1643), c(1646), c(1650), c(1654), c(1657), c(1661), c(1664), c(1668), c(1671), c(1675), c(1678), c(1682), c(1685), c(1689), c(1693), c(1696), c(1700), c(1703), c(1707), c(1710), c(1714), c(1717), c(1721), c(1725), c(1728), c(1732), c(1735), c(1739), c(1742), c(1746), c(1749), c(1753), c(1756), c(1760), c(1764), c(1767), c(1771), c(1774), c(1778), c(1781), c(1785), c(1788), c(1792), c(1796), c(1799), c(1803), c(1806), c(1810), c(1813), c(1817), c(1820), c(1824), c(1827), c(1831), c(1835), c(1838), c(1842), c(1845), c(1849), c(1852), c(1856), c(1859), c(1863), c(1867), c(1870), c(1874), c(1877), c(1881), c(1884), c(1888), c(1891), c(1895), c(1898), c(1902), c(1906), c(1909), c(1913), c(1916), c(1920), c(1923), c(1927), c(1930), c(1934)

are not transmitted.

The result is a block of 1392 coded bits, {c(0),c(1),…, c(1391)}.

3.12.4 Interleaving

The coded bits are reordered and interleaved according to the following rule:

i(B,j) = c(n,k), for k = 0,1,…,1391

n = 0,1,…,N,N+1,…

B = B0 + 4n + (k mod 12)

j = 3*[(49*(k+int(k/348)) mod 116) + int[(k mod 12)/4]

The result of the interleaving is a distribution of the reordered 348 bits of a given data block, n = N, over 12 blocks, 29 bits equally distributed in each block. The block of coded data is interleaved "diagonal", where a new block of coded data starts with every fourth burst and is distributed over 12 bursts.

3.12.5 Mapping on a Burst

The mapping is given by the rule:

e(B,j) = i(B,j) for j = 0,1,…,347

NOTE: No stealing flags are used.