4.10A Coding for E-ROCH
25.2123GPPMultiplexing and channel coding (FDD)Release 17TS
The following information is transmitted by means of the E-DCH rank and offset channel (E-ROCH):
– S-ETFC Offset: xseo,1, xseo,2, …, xseo,5
– Rank Indication: xri,1
4.10A.1 Overview
The E-ROCH coding chain uses the same coding chain as the E-AGCH. Figure 24B below illustrates the overall coding chain for the E-ROCH.
Figure 24B: Coding for E-ROCH
4.10A.2 E-ROCH information field mapping
4.10A.2.1 Information field mapping of the S-ETFC Offset
The S-ETFC Offset information is specified in Table 16D. The values are mapped such that xseo,1 corresponds to the MSB of the index.
Table 16D: Mapping of S-ETFC Offset value
|
S-ETFC Offset Value |
Index |
|
60/30 |
31 |
|
55/30 |
30 |
|
50/30 |
29 |
|
45/30 |
28 |
|
40/30 |
27 |
|
35/30 |
26 |
|
30/30 |
25 |
|
28/30 |
24 |
|
26/30 |
23 |
|
24/30 |
22 |
|
22/30 |
21 |
|
21/30 |
20 |
|
20/30 |
19 |
|
19/30 |
18 |
|
18/30 |
17 |
|
17/30 |
16 |
|
16/30 |
15 |
|
15/30 |
14 |
|
14/30 |
13 |
|
13/30 |
12 |
|
12/30 |
11 |
|
11/30 |
10 |
|
10/30 |
9 |
|
9/30 |
8 |
|
8/30 |
7 |
|
7/30 |
6 |
|
6/30 |
5 |
|
5/30 |
4 |
|
4/30 |
3 |
|
3/30 |
2 |
|
2/30 |
1 |
|
1/30 |
0 |
4.10A.2.2 Information field mapping of the Rank Indication
The value of xri,1 is set as specified in Table 16E.
Table 16E: Mapping of Rank Indication
|
Rank Indication |
xri,1 |
|
"Rank 2 allowed" |
1 |
|
"Rank 2 not allowed" |
0 |
4.10A.3 Multiplexing of E-ROCH information
The S-ETFC Offset information xseo,1, xseo,2, …, xseo,5 and the Rank Indication information xri,1 are multiplexed together. This gives a sequence of bits xro,1, xro,2, …, xro, 6 where
xro,k = xseo,k k=1,2,…,5
xro,6 = xri,1
4.10A.4 CRC attachment for E-ROCH
The S-E-RNTI is the E‑DCH Radio Network Identifier specific to E-ROCH defined in [13]. It is mapped such that xid,1 corresponds to the MSB.
From the sequence of bits xro,1, xro,2, …, xro,6 a 16 bit CRC is calculated according to clause 4.2.1.1. That gives the sequence of bits c1, c2, …, c16 where
k=1,2,…,16
This sequence of bits is then masked with xid,1, xid,2, …, xid,16 and appended to the sequence of bits xro,1, xro,2, …, xro,6 to form the sequence of bits y1, y2, …, y22 where
yi=xro,i i=1,2, …,6
yi=(ci-6 + xid,i-6) mod 2 i= 7, …, 22
4.10A.5 Channel coding for E-ROCH
Rate 1/3 convolutional coding, as described in Clause 4.2.3.1 is applied to the sequence of bits y1, y2, …, y22, resulting in the sequence of bits z1, z2, …, z90.
4.10A.6 Rate matching for E-ROCH
From the input sequence z1, z2, …, z90 the bits z1, z2, z5, z6, z7, z11, z12, z14, z15, z17, z23, z24, z31, z37, z44, z47, z61, z63, z64, z71, z72, z75, z77, z80, z83, z84, z85, z87, z88, z90 are punctured to obtain the output sequence r1, r2, …, r60.
4.10A.7 Physical channel mapping for E-ROCH
The E-ROCH sub frame is described in [2]. The sequence of bits r1, r2, …, r60 is mapped to the corresponding E-ROCH sub frame. The bits rk are mapped so that they are transmitted over the air in ascending order with respect to k.