4.4 Coding for layer 1 control for the 1.28 Mcps option
25.2223GPPMultiplexing and channel coding (TDD)Release 17TS
4.4.1 Coding of transport format combination indicator (TFCI) for QPSK and 16QAM
The coding of TFCI for 1.28Mcps TDD is same as that of 3.84Mcps TDD.cf.[4.3.1 ‘Coding of transport format combination indicator’].
4.4.1.1 Mapping of TFCI code word
Denote the number of bits in the TFCI code word by NTFCI code word, and denote the TFCI code word bits by bk, where k = 0, …, NTFCI code word -1
When the number of bits in the TFCI code word is 8, 16, 32, the mapping of the TFCI code word to the TFCI bit positions shall be as follows:
Figure 9: Mapping of TFCI code word bits to TFCI position in 1.28 Mcps TDD option,
where N = NTFCI code word.
For MBSFN transmissions with 16QAM, the coded bits bk, are mapped to the transmitted TFCI bits according to the following two group formulas:
Formula a, mapping onto the outer-corners of the 16QAM constellation
d4k = b2k ,
d4k+1 = b2k+1 ,
d4k+2 = 1,
d4k+3 = 1,
Formula b, mapping onto the inner-corners of the 16QAM constellation
d4k = b2k ,
d4k+1 = b2k+1 ,
d4k+2 =0,
d4k+3 = 0,
The 1st, the 3rd, the 5th and the 7th part of TFCI code word will use the Mapping Formula a, and the 2nd, the 4th, the 6th and the 8th part of TFCI code word will use the Mapping Formula b. As the TTI of S-CCPCH is 40ms or 80ms, the TFCI bits will be repeated with a period of 20ms frame. In the second 20ms frame, the 1st, the 3rd, the 5th and the 7th part of TFCI code word will use the Mapping Formula b, and the 2nd, the 4th, the 6th and 8th part of TFCI code word will use the Mapping Formula a, and so on for the consecutive frames. The mapping of the TFCI code word to the TFCI bit positions shall be as follows:
Figure 9A: Mapping of TFCI code word bits to TFCI position in 1.28 Mcps TDD option for downlink MBSFN, where N = NTFCI code word.
When the number of bits of the TFCI code word is 4 , then the TFCI code word is equally divided into two parts for the consecutive two subframe and mapped onto the end of the first data field in each of the consecutive subframes.The mapping for NTFCI code word =4 is shown in figure 10:
Figure 10: Mapping of TFCI code word bits to TFCI position in 1.28 Mcps TDD option,
when NTFCI code word.=4
The location of the 1st to 4th parts of the TFCI code word in the timeslot is defined in [7].
If the shortest transmission time interval of any constituent TrCH is at least 20 ms, then successive TFCI code words in the frames within the TTI shall be identical. If a TFCI is transmitted on multiple timeslots in a frame each timeslot shall have the same TFCI code word.
4.4.2 Coding of transport format combination indicator (TFCI) for 8PSK
Encoding of TFCI bits depends on the number of them and the modulation in use. When 2 Mcps service is transmitted, 8PSK modulation is applied in 1.28 Mcps TDD option. The encoding scheme for TFCI when the number of bits are 6 – 10, and less than 6 bits is described in section 4.4.2.1 and 4.4.2.2, respectively.
4.4.2.1 Coding of long TFCI lengths
When the number of TFCI bits is 6 – 10, the TFCI bits are encoded by using a (64,10) sub-code of the second order Reed-Muller code, then 16 bits out of 64 bits are punctured (Puncturing positions are 0, 4, 8, 13, 16, 20, 27, 31, 34, 38, 41, 44, 50, 54, 57, 61st bits). The coding procedure is shown in Figure 11.
Figure 11: Channel coding of long TFCI bits for 8PSK
If the TFCI consists of less than 10 bits, it is padded with zeros to 10 bits, by setting the most significant bits to zero. The code words of the punctured (48,10) sub-code of the second order Reed-Muller codes are linear combination of 10 basis sequences. The basis sequences are shown in Table 11.
Table 11: Basis sequences for (48,10) TFCI code
|
I |
Mi,0 |
Mi,1 |
Mi,2 |
Mi,3 |
MI,4 |
Mi,5 |
Mi,6 |
MI,7 |
MI,8 |
Mi,9 |
|---|---|---|---|---|---|---|---|---|---|---|
|
0 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
|
1 |
0 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
|
2 |
1 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
|
3 |
1 |
0 |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
|
4 |
0 |
1 |
1 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
|
5 |
1 |
1 |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
|
6 |
1 |
0 |
0 |
1 |
0 |
0 |
1 |
1 |
1 |
1 |
|
7 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
1 |
0 |
1 |
|
8 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
0 |
1 |
0 |
|
9 |
0 |
0 |
1 |
1 |
0 |
0 |
1 |
1 |
0 |
0 |
|
10 |
0 |
1 |
1 |
1 |
0 |
0 |
1 |
1 |
0 |
1 |
|
11 |
1 |
1 |
1 |
1 |
0 |
0 |
1 |
1 |
1 |
1 |
|
12 |
1 |
0 |
0 |
0 |
1 |
0 |
1 |
0 |
1 |
1 |
|
13 |
0 |
1 |
0 |
0 |
1 |
0 |
1 |
1 |
1 |
0 |
|
14 |
1 |
1 |
0 |
0 |
1 |
0 |
1 |
0 |
0 |
1 |
|
15 |
1 |
0 |
1 |
0 |
1 |
0 |
1 |
0 |
1 |
1 |
|
16 |
0 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
0 |
|
17 |
1 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
1 |
0 |
|
18 |
0 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
0 |
1 |
|
19 |
1 |
0 |
0 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
|
20 |
0 |
1 |
0 |
1 |
1 |
0 |
1 |
0 |
1 |
0 |
|
21 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
0 |
1 |
0 |
|
22 |
1 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
0 |
1 |
|
23 |
0 |
1 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
0 |
|
24 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
|
25 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
0 |
|
26 |
1 |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
|
27 |
0 |
0 |
1 |
0 |
0 |
1 |
1 |
0 |
1 |
1 |
|
28 |
1 |
0 |
1 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
|
29 |
1 |
1 |
1 |
0 |
0 |
1 |
1 |
0 |
1 |
1 |
|
30 |
0 |
0 |
0 |
1 |
0 |
1 |
1 |
0 |
0 |
1 |
|
31 |
0 |
1 |
0 |
1 |
0 |
1 |
1 |
0 |
0 |
1 |
|
32 |
1 |
1 |
0 |
1 |
0 |
1 |
1 |
1 |
1 |
1 |
|
33 |
1 |
0 |
1 |
1 |
0 |
1 |
1 |
0 |
0 |
1 |
|
34 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
|
35 |
1 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
0 |
1 |
|
36 |
0 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
0 |
|
37 |
1 |
0 |
0 |
0 |
1 |
1 |
1 |
0 |
1 |
1 |
|
38 |
1 |
1 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
|
39 |
0 |
0 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
0 |
|
40 |
1 |
0 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
0 |
|
41 |
1 |
1 |
1 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
|
42 |
0 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
|
43 |
0 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
1 |
0 |
|
44 |
1 |
1 |
0 |
1 |
1 |
1 |
1 |
0 |
1 |
0 |
|
45 |
0 |
0 |
1 |
1 |
1 |
1 |
1 |
0 |
1 |
1 |
|
46 |
0 |
1 |
1 |
1 |
1 |
1 |
1 |
0 |
0 |
1 |
|
47 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
0 |
0 |
Let’s define the TFCI bits as a0 , a1 , a2 , a3 , a4 , a5 , a6 , a7 , a8 , a9, where a0 is the LSB and a9 is the MSB. The TFCI bits shall correspond to the TFC index (expressed in unsigned binary form) defined by the RRC layer to reference the TFC of the CCTrCH in the associated radio frame.
The output TFCI code word bits bi are given by:
where i=0…47. NTFCI code word =48.
4.4.2.2 Coding of short TFCI lengths
4.4.2.2.1 Coding very short TFCIs by repetition
When the number of TFCI bits is 1 or 2, then repetition will be used for the coding. In this case, each bit is repeated to a total of 6 times giving 6-bit transmission (NTFCI code word = 6) for a single TFCI bit and 12-bit transmission (NTFCI code word = 12) for 2 TFCI bits. The TFCI bit(s) a0 (or a0 and a1 where a0 is the LSB) shall correspond to the TFC index (expressed in unsigned binary form) defined by the RRC layer to reference the TFC of the CCTrCH in the associated radio frame.
In the case of NTFCI code word=6, the TFCI codeword {b0, b1, b2, b3, b4, b5} is equal to the sequence {a0, a0, a0, a0, a0, a0}.
In the case of NTFCI code word=12, the TFCI codeword {b0, b1, … , b11} is equal to the sequence {a0, a1, a0, a1, a0, a1, a0, a1, a0, a1, a0, a1}.
4.4.2.2.2 Coding short TFCIs using bi-orthogonal codes
If the number of TFCI bits is in the range of 3 to 5, the TFCI bits are encoded using a (32,5) first order Reed-Muller code, then 8 bits out of 32 bits are punctured (Puncturing positions are 0, 1, 2, 3, 4, 5, 6, 7th bits). The coding procedure is shown in Figure 12.
Figure 12: Channel coding of short TFCI bits for 8PSK
If the TFCI consists of less than 5 bits, it is padded with zeros to 5 bits, by setting the most significant bits to zero. The code words of the punctured (32,5) first order Reed-Muller codes are linear combination of 5 basis sequences shown in Table 12.
Table 12: Basis sequences for (24,5) TFCI code
|
I |
Mi,0 |
Mi,1 |
Mi,2 |
Mi,3 |
Mi,4 |
|
0 |
0 |
0 |
0 |
1 |
0 |
|
1 |
1 |
0 |
0 |
1 |
0 |
|
2 |
0 |
1 |
0 |
1 |
0 |
|
3 |
1 |
1 |
0 |
1 |
0 |
|
4 |
0 |
0 |
1 |
1 |
0 |
|
5 |
1 |
0 |
1 |
1 |
0 |
|
6 |
0 |
1 |
1 |
1 |
0 |
|
7 |
1 |
1 |
1 |
1 |
0 |
|
8 |
0 |
0 |
0 |
0 |
1 |
|
9 |
1 |
0 |
0 |
0 |
1 |
|
10 |
0 |
1 |
0 |
0 |
1 |
|
11 |
1 |
1 |
0 |
0 |
1 |
|
12 |
0 |
0 |
1 |
0 |
1 |
|
13 |
1 |
0 |
1 |
0 |
1 |
|
14 |
0 |
1 |
1 |
0 |
1 |
|
15 |
1 |
1 |
1 |
0 |
1 |
|
16 |
0 |
0 |
0 |
1 |
1 |
|
17 |
1 |
0 |
0 |
1 |
1 |
|
18 |
0 |
1 |
0 |
1 |
1 |
|
19 |
1 |
1 |
0 |
1 |
1 |
|
20 |
0 |
0 |
1 |
1 |
1 |
|
21 |
1 |
0 |
1 |
1 |
1 |
|
22 |
0 |
1 |
1 |
1 |
1 |
|
23 |
1 |
1 |
1 |
1 |
1 |
Let’s define the TFCI bits as a0 , a1 , a2 , a3 , a4, where a0 is the LSB and a4 is the MSB. The TFCI bits shall correspond to the TFC index (expressed in unsigned binary form) defined by the RRC layer to reference the TFC of the CCTrCH in the associated radio frame.
The output code word bits bi are given by:
where i=0…23. NTFCI code word =24.
4.4.2.3 Mapping of TFCI code word
Denote the number of bits in the TFCI code word by NTFCI code word, and denote the TFCI code word bits by bk, where k = 0, …, NTFCI code word -1.
When the number of bits in the TFCI code word is 12, 24 or 48, the mapping of the TFCI code word to the TFCI bit positions in a time slot shall be as follows.
Figure 13: Mapping of TFCI code word bits to timeslot in 1.28 Mcps TDD option,
where N = NTFCI code word.
When the number of bits in the TFCI code word is 6, the TFCI code word is equally divided into two parts for the consecutive two sub-frames and mapped onto the first data field in each of the consecutive sub-frames. The mapping of the TFCI code word to the TFCI bit positions in a time slot shall be as shown in figure 14.
Figure 14: Mapping of TFCI code word bits to timeslot in 1.28 Mcps TDD option when NTFCI code word = 6
The location of the 1st to 4th parts of the TFCI code word in the timeslot is defined in [7].
4.4.3 Coding and Bit Scrambling of the Paging Indicator
The paging indicator Pq, q = 0, …, NPI-1, Pq {0, 1} is an identifier to instruct the UE whether there is a paging message for the groups of mobiles that are associated to the PI, calculated by higher layers, and the associated paging indicator Pq. The length LPI of the paging indicator is LPI=2, LPI=4 or LPI=8 symbols. NPIB = 2*NPI*LPI bits are used for the paging indicator transmission in one radio frame. The mapping of the paging indicators to the bits ei, i = 1, …, NPIB is shown in table 13.
Table 13: Mapping of the paging indicator
|
Pq |
Bits {e2LPI*q+1, e2LPI*q+2, … ,e2LPI*(q+1) } |
Meaning |
|
0 |
{0, 0, …, 0} |
There is no necessity to receive the PCH |
|
1 |
{1, 1, …, 1} |
There is the necessity to receive the PCH |
If the number S of bits in one radio frame available for the PICH is bigger than the number NPIB of bits used for the transmission of paging indicators, the sequence e = {e1, e2, …, eNPIB} is extended by S–NPIB bits that are set to zero, resulting in a sequence h = {h1, h2, …, hS}:
The bits hk , k = 1, …, S on the PICH then undergo bit scrambling as defined in section 4.2.9.
The bits sk, k = 1, …, S output from the bit scrambler are then transmitted over the air as shown in [7].
4.4.4 Coding of the Fast Physical Access Channel (FPACH) information bits
The FPACH burst is composed by 32 information bits which are block coded and convolutional coded, and then delivered in one sub-frame as follows:
1. The 32 information bits are protected by 8 parity bits for error detection as described in sub-clause 4.2.1.1.
2. Convolutional code with constraint length 9 and coding rate ½ is applied as described in sub-clause 4.2.3.1. The size of data block c(k) after convolutional encoder is 96 bits.
3. To adjust the size of the data block c(k) to the size of the FPACH burst, 8 bits are punctured as described in sub-clause 4.2.7 with the following clarifications:
– Ni;j =96 is the number of bits in a radio sub-frame before rate matching
– Ni,,j = -8 is the number of bits to punctured in a radio sub-frame
– eini = a x Nij
The 88 bits after rate matching are then delivered to the intra-frame interleaving.
4. The bits in input to the interleaving unit are denoted as {x(0), …, x(87)}. The coded bits are block rectangular interleaved according to the following rule: the input is written row by row, the output is read column by column.
Hence, the interleaved sequence is denoted by y (i) and are given by:
y(0), y(1), …, y(87)=x(0), x(8), …,x(80),x(1), …, x(87).
4.4.5 Coding and Bit Scrambling of the MBMS Notification Indicator
The MBMS notification indicator Nq, q = 0, …, Nn-1, Nq {0, 1} is an identifier to instruct the UE whether there is an MBMS notification indication for the groups of MBMS services that are associated to the NI, calculated by higher layers, and the associated MBMS notification indicator Nq. The length LNI of the MBMS notification indicator is LNI=2, LNI=4 or LNI=8 symbols. NNIB = 2*Nn*LNI bits are used for the MBMS notification indicator transmission in one MICH. The mapping of the MBMS notification indicators to the bits ei, i = 1, …, NNIB is shown in table 13A.
Table 13A: Mapping of the MBMS notification indicator
|
Nq |
Bits {e2LNI*q+1, e2LNI*q+2, … ,e2LNI*(q+1) } |
|
0 |
{0, 0, …, 0} |
|
1 |
{1, 1, …, 1} |
If the number S of bits available for the MICH is bigger than the number NNIB of bits used for the transmission of MBMS notification indicators, the sequence e = {e1, e2, …, eNNIB} is extended by S–NNIB bits that are set to zero, resulting in a sequence h = {h1, h2, …, hS}:
The bits hk , k = 1, …, S on the MICH then undergo bit scrambling as defined in section 4.2.9.
The bits sk, k = 1, …, S output from the bit scrambler are then transmitted over the air as shown in [7].
4.4.6 Coding of PLCCH
The PLCCH is a Node-B terminated channel used to carry dedicated (UE-specific) TPC and SS information to multiple UEs. Each TPC/SS command pair for a given UE is mapped to 3 bits as shown in table 13B.
Table 13B: Mapping of the TPC/SS pair
|
3-bit TPC/SS command (MSB on left) |
TPC command |
SS command |
|
000 |
‘DOWN’ |
‘DOWN’ |
|
100 |
‘UP’ |
‘DOWN’ |
|
011 |
‘DOWN’ |
‘UP’ |
|
111 |
‘UP’ |
‘UP’ |
|
001 |
‘DOWN’ |
‘Do Nothing’ |
|
101 |
‘UP’ |
‘Do Nothing’ |
Let I=14 be the number of TPC/SS command pairs that can be carried by a single PLCCH. The 3 bits corresponding to the ith TPC/SS command pair ( i=1…I ), are denoted {, , } where is the MSB.
The bit sequence corresponding to the I=14 TPC/SS command pairs is denoted (k = 0,1,2,…41). (n=0,1,2) is mapped to such that:
The PLCCH burst is composed of 44 information bits {bplcch(0), bplcch(1),…,bplcch(43)} which are repetition coded, and then delivered in one sub-frame as follows:
1. bplcch(m)= (for m=0,1,…41) and bplcch(m) = 0 (for m=42,43)
2. Repetition coding with code rate ½ is applied to the sequence {bplcch(0),…,bplcch(43)} in order to form the sequence {x(0), x(1), x(2), x(3),…, x(86), x(87)}. The size of the data block after the repetition encoder is 88 bits. The encoded codeword {x(0), x(1), x(2), x(3),…,x(86), x(87)} is equal to {bplcch (0), bplcch (0), bplcch (1), bplcch (1),…,bplcch (43), bplcch (43)}.
3. The bits output from the repetition encoder {x(0), …, x(87)} are input to an interleaving unit. The coded bits are block rectangular interleaved according to the following rule: the input is written row by row, the output is read column by column.
Hence, the interleaved sequence is denoted by y(i) and is given by:
y(0), y(1), …, y(87) = x(0), x(8), …, x(80), x(1), …, x(87).
The bit sequence y(0), y(1), … y(87) is mapped to the PLCCH burst in order of bit index, with the lowest bit index being the first bit (in time) to be transmitted.