## 4.2.5 1^{st} interleaving

25.2123GPPMultiplexing and channel coding (FDD)Release 17TS

#### 4.2.5.1 Void

#### 4.2.5.2 1^{st} interleaver operation

The 1^{st} interleaving is a block interleaver with inter-column permutations. The input bit sequence to the block interleaver is denoted by , where *i* is TrCH number and *X _{i}* the number of bits. Here

*X*is guaranteed to be an integer multiple of

_{i}*F*. The output bit sequence from the block interleaver is derived as follows:

_{i}(1) Select the number of columns C1 from Table 4 or 4A depending on the TTI. The columns are numbered 0, 1, …, C1 – 1 from left to right. Table 4A is used in uplink when UL_DPCH_10ms_Mode is configured by higher layers, and Table 4 is used in all other cases.

(2) Determine the number of rows of the matrix, R1 defined as

R1 = *X _{i }*/ C1.

The rows of the matrix are numbered 0, 1, …, R1 – 1 from top to bottom.

(3) Write the input bit sequence into the R1 C1 matrix row by row starting with bit in column 0 of row 0 and ending with bit in column C1 – 1 of row R1 – 1:

(4) Perform the inter-column permutation for the matrix based on the pattern shown in table 4, where P1_{C1} (*j*) is the original column position of the *j*-th permuted column. After permutation of the columns, the bits are denoted by *y _{ik}*:

(5) Read the output bit sequence of the block interleaver column by column from the inter-column permuted R1 C1 matrix. Bit corresponds to row 0 of column 0 and bit corresponds to row R1 – 1 of column C1 – 1.

Table 4: Inter-column permutation patterns for 1st interleaving for downlink, and for uplink when UL_DPCH_10ms_Mode is not configured by higher layers

TTI |
Number of columns C1 |
Inter-column permutation patterns <P1 |

10 ms |
1 |
<0> |

20 ms |
2 |
<0,1> |

40 ms |
4 |
<0,2,1,3> |

80 ms |
8 |
<0,4,2,6,1,5,3,7> |

Table 4A: Inter-column permutation patterns for 1st interleaving for uplink when UL_DPCH_10ms_Mode is configured by higher layers

TTI |
Number of columns C1 |
Inter-column permutation patterns <P1 |

20 ms |
1 |
<0> |

40 ms |
2 |
<0,1> |

80 ms |
4 |
<0,2,1,3> |

#### 4.2.5.3 Relation between input and output of 1^{st} interleaving in uplink

The bits input to the 1^{st} interleaving are denoted by , where *i* is the TrCH number and *T _{i}* the number of bits. Hence, x

*and X*

_{i,k}= t_{i,k}

_{i}*=*

*T*.

_{i}The bits output from the 1^{st} interleaving are denoted by , and d* _{i,k} = y_{i,k}*.

#### 4.2.5.4 Relation between input and output of 1^{st} interleaving in downlink

If fixed positions of the TrCHs in a radio frame is used then the bits input to the 1^{st} interleaving are denoted by , where *i* is the TrCH number. Hence, x* _{ik} = h_{ik}* and X

*.*

_{i}= D_{i}If flexible positions of the TrCHs in a radio frame is used then the bits input to the 1^{st} interleaving are denoted by , where *i* is the TrCH number. Hence, x* _{ik} = g_{ik}* and X

*.*

_{i}= G_{i}The bits output from the 1^{st} interleaving are denoted by , where *i* is the TrCH number and *Q _{i}* is the number of bits. Hence,

*q*,

_{ik}= y_{ik}*Q*=

_{i}*F*if fixed positions are used, and

_{i}H_{i}*Q*=

_{i}*G*if flexible positions are used.

_{i}*H*is defined in subclause 4.2.9.1.

_{i}