## 4.6 Coding for HS-SCCH type 1

25.2123GPPMultiplexing and channel coding (FDD)Release 17TS

### 4.6.1 Overview

HS-SCCH shall be of type 1 when the following two conditions are both true:

– the UE is not configured in MIMO mode and not in MIMO mode with four transmit antennas, and

– the conditions for usage of HS-SCCH type 2 are not met.

In this section, the terms “HS-SCCH” and “HS-SCCH type 1” are used interchangeably.

The following information is transmitted by means of the HS-SCCH type 1 physical channel.

– Channelization-code-set information (7 bits): *x _{ccs,1}, x_{ccs,2}, …, x_{ccs,7}*

– Modulation scheme information (1 bit): *x _{ms,1}*

– Transport-block size information (6 bits): *x _{tbs,1}, x_{tbs,2}, …, x_{tbs,6}*

– Hybrid-ARQ process information (3 bits): *x _{hap,1}, x_{hap,2}, x_{hap,3}*

– Redundancy and constellation version (3 bits): *x _{rv,1}, x_{rv,2}, x_{rv,3}*

– New data indicator (1 bit): *x _{nd,1}*

– UE identity (16 bits): *x _{ue,1}, x_{ue,2}, …, x_{ue,16}*

For an HS-SCCH order,

– x_{ccs,1}, x_{ccs,2}, …, x_{ccs,7}, x_{ms,1} shall be set to ”11100000’

– x_{tbs,1}, x_{tbs,2}, …, x_{tbs,}_{4} shall be set to ”1111’

– x_{tbs,5}, _{tbs,6} shall be set to x_{eodt,1}, x_{eodt,2}

– x_{hap,1}, x_{hap,2}, x_{hap,3}, x_{rv,1}, x_{rv,2}, x_{rv,3} shall be set to x_{odt,1}, x_{odt,2}, x_{odt,3}, x_{ord,1}, x_{ord,2}, x_{ord,3}

– x_{nd,1} is reserved

where *x _{eodt,1}, x_{eodt,2}, x_{odt,1}, x_{odt,2}, x_{odt,3}, x_{ord,1}, x_{ord,2}, x_{ord,3}* are defined in subclause 4.6C.

Figure 19 below illustrates the overall coding chain for HS-SCCH type 1.

Figure 19: Coding chain for HS-SCCH type 1

### 4.6.2 HS-SCCH information field mapping

#### 4.6.2.1 Redundancy and constellation version coding

The redundancy version (RV) parameters *r*, *s* and constellation version parameter *b* are coded jointly to produce the value X_{rv}. X_{rv} is alternatively represented as the sequence x_{rv,1}, x_{rv,2}, x_{rv,3} where x_{rv,1} is the MSB. This is done according to tables 12 and 13 according to the modulation mode used:

Table 12: RV coding for 16QAM and 64QAM

X |
s |
R |
b |

0 |
1 |
0 |
0 |

1 |
0 |
0 |
0 |

2 |
1 |
1 |
1 |

3 |
0 |
1 |
1 |

4 |
1 |
0 |
1 |

5 |
1 |
0 |
2 |

6 |
1 |
0 |
3 |

7 |
1 |
1 |
0 |

Table 13: RV coding for QPSK

X |
s |
r |

0 |
1 |
0 |

1 |
0 |
0 |

2 |
1 |
1 |

3 |
0 |
1 |

4 |
1 |
2 |

5 |
0 |
2 |

6 |
1 |
3 |

7 |
0 |
3 |

#### 4.6.2.2 Modulation scheme mapping

The value of *x _{ms,1}* is derived from the modulation and given by the following:

#### 4.6.2.3 Channelization code-set mapping

The channelization code-set bits x_{ccs,1}, x_{ccs,2}, …, x_{ccs,7} are coded according to the following:

Given P (multi-)codes starting at code O, and given the HS-SCCH number if 64QAM is configured for the UE and x_{ms,1}=1, calculate the information-field using the unsigned binary representation of integers calculated by the expressions,

for the first three bits (code group indicator) of which *x _{ccs,1}* is the MSB:

*x _{ccs,1}, x_{ccs,2}, x_{ccs,3}* = min(P-1,15-P)

If 64QAM is not configured for the UE, or if 64QAM is configured and x_{ms,1}=0, then

for the last four bits (code offset indicator) of which *x _{ccs,4}* is the MSB:

*x _{ccs,4}, x_{ccs,5, }x_{ccs,6}, x_{ccs,7}* = |O-1-P/8 *15|

Otherwise (i.e. if 64QAM is configured for the UE and x_{ms,1}=1),

*P* and *O* shall fulfil |O-1-P/8 *15| mod 2 = (HS‑SCCH number) mod 2, and then

*x _{ccs,4}, x_{ccs,5, }x_{ccs,6}, x_{ccs,dummy}* = |O-1-P/8 *15|, where

*x*is a dummy bit that is not transmitted on HS-SCCH.

_{ccs,dummy}Furthermore,

.

The definitions of P and O are given in [3]. The HS-SCCH number is given by the position in the list of HS-SCCH Channelisation Code Informations signalled by higher layers. The HS-SCCH number is associated with the code offset indicator and code group indicator as described above if 64QAM is configured for the UE and x_{ms,1}=1.

#### 4.6.2.4 UE identity mapping

The UE identity is the HS-DSCH Radio Network Identifier (H-RNTI) defined in [13]. This is mapped such that x_{ue,1 } corresponds to the MSB and x_{ue,16} to the LSB, cf. [14].

#### 4.6.2.5 HARQ process identifier mapping

Hybrid-ARQ process information (3 bits) *x _{hap,1}, x_{hap,2}, x_{hap,3}* is the unsigned binary representation of the HARQ process identifier where

*x*is MSB.

_{hap,1}#### 4.6.2.6 Transport block size index mapping

Transport-block size information (6 bits) *x _{tbs,1}, x_{tbs,2}, …, x_{tbs,6 }* is unsigned binary representation of the transport block size index where

*x*is MSB.

_{tbs,1}### 4.6.3 Multiplexing of HS-SCCH information

The channelization-code-set information *x _{ccs,1}, x_{ccs,2}, …, x_{ccs,7}* and modulation-scheme information

*x*are multiplexed together. This gives a sequence of bits

_{ms,1}*x*where

_{1,1}, x_{1,2}, …, x_{1,8}*x _{1,i} = x_{ccs,i} i=1,2,…,7*

*x _{1,i} = x_{ms,i-7 }i=8*

The transport-block-size information *x _{tbs,1}, x_{tbs,2}, …, x_{tbs,6}*, Hybrid-ARQ-process information

*x*, redundancy-version information

_{hap,1},x_{hap,2}, x_{hap,3}*x*, x

_{rv,1}, x_{rv,2}_{rv,3}and new-data indicator

*x*are multiplexed together. This gives a sequence of bits

_{nd,1}*x*where

_{2,1}, x_{2,2}, …, x_{2,13}*x _{2,i} = x_{tbs,i} i=1,2,…,6*

*x _{2,i} = x_{hap,i-6 }i=7,8,9 *

*x _{2,i} = x_{rv,i-9} i=10,11,12*

*x _{2,i} = x_{nd,i-12 }i=13*

### 4.6.4 CRC attachment for HS-SCCH

From the sequence of bits *x _{1,1}, x_{1,2}, …, x_{1,8, }x_{2,1}, x_{2,2}, …, x_{2,13}* a 16 bits CRC is calculated according to Clause 4.2.1.1. This gives a sequence of bits

*c*where

_{1}, c_{2}, …, c_{16 }_{ }k=1,2,…,16

This sequence of bits is then masked with the UE Identity *x _{ue,1}, x_{ue,2}, …, x_{ue,16}* and then appended to the sequence of bits

*x*to form the sequence of bits

_{2,1}, x_{2,2}, …, x_{2,13}*y*, where

_{1}, y_{2}, …, y_{29}*y _{i} = x_{2,i} i=1,2,…,13*

*y _{i} = *(

*c*+

_{i-13}*x*,

_{ue}_{i-13}) mod 2

*i=14,15,…,29*

### 4.6.5 Channel coding for HS-SCCH

Rate 1/3 convolutional coding, as described in Clause 4.2.3.1, is applied to the sequence of bits x_{1,1},x_{1,2}, …,x_{1,8}_{. }This gives a sequence of bits *z _{1,1}, z_{1,2}, …, z_{1,48}*

_{.}

Rate 1/3 convolutional coding, as described in Clause 4.2.3.1, is applied to the sequence of bits *y _{1}, y_{2}, …, y_{29}*

_{. }This gives a sequence of bits

*z*

_{2,1}, z_{2,2}, …, z_{2,111}_{.}

Note that the coded sequence lengths result from the termination of K=9 convolutional coding being fully applied.

### 4.6.6 Rate matching for HS-SCCH

From the input sequence *z _{1,1}, z_{1,2}, …, z_{1,48}* the bits

*z*are punctured to obtain the output sequence

_{1,1}, z_{1,2}, z_{1,4}, z_{1,8}, z_{1,42}, z_{1,45}, z_{1,47}, z_{1,48}*r*.

_{1,1},r_{1,2}…r_{1,40}From the input sequence *z _{2,1}, z_{2,2}, …, z_{2,111}* the bits

*z*are punctured to obtain the output sequence

_{2,1}, z_{2,2}, z_{2,3}, z_{2,4}, z_{2,5}, z_{2,6}, z_{2,7}, z_{2,8}, z_{2,12}, z_{2,14}, z_{2,15}, z_{2,24}, z_{2,42}, z_{2,48}, z_{2,54}, z_{2,57}, z_{2,60}, z_{2,66}, z_{2,69}, z_{2,96}, z_{2,99}, z_{2,101}, z_{2,102}, z_{2,104}, z_{2,105}, z_{2,106}, z_{2,107}, z_{2,108}, z_{2,109}, z_{2,110}, z_{2,111}*r*.

_{2,1},r_{2,2}…r_{2,80}### 4.6.7 UE specific masking for HS-SCCH

The rate matched bits *r _{1,1},r_{1,2}…r_{1,40}* shall be masked in an UE specific way using the UE identity

*x*to produce the bits

_{ue,1}, x_{ue,2}, …, x_{ue,16},_{ }*s*.

_{1,1},s_{1,2}…s_{1,40}Intermediate code word bits b_{i}, i=1,2…,48, are defined by encoding the UE identity bits using the rate ½ convolutional coding described in Clause 4.2.3.1. Eight bits out of the resulting 48 convolutionally encoded bits are punctured using the rate matching rule of Clause 4.6.6 for the HS-SCCH part 1 sequence, that is, the intermediate code word bits b_{1}, b_{2}, b_{4}, b_{8}, b_{42}, b_{45}, b_{47}, b_{48, }are_{ }punctured to obtain the 40 bit UE specific scrambling sequence c_{1}, c_{2}, ….c_{40}. .

The mask output bits *s _{1,1},s_{1,2}…s_{1,40}* are calculated as follows:

*s _{1,k} =*(

*r*)

_{1,k}+ c_{k}*mod 2*for k = 1,2…40

### 4.6.8 Physical channel mapping for HS-SCCH

The HS-SCCH sub-frame is described in[2].

The sequence of bits *s _{1,1}, s_{1,2},, …, s_{1,40} *is mapped to the first slot of the HS-SCCH sub frame. The bits

*s*are mapped to the PhCHs so that the bits for each PhCH are transmitted over the air in ascending order with respect to

_{1,k}*k*.

The sequence of bits *r _{2,1}, r_{2,2},, …,,r_{2,80} *is mapped to the second and third slot of the HS-SCCH sub frame. The bits

*r*are mapped to the PhCHs so that the bits for each PhCH are transmitted over the air in ascending order with respect to

_{2,k}*k*.