4.6 Coding/Multiplexing for HS-SCCH

25.2223GPPMultiplexing and channel coding (TDD)Release 17TS

For 1.28 Mcps TDD, HS-SCCH shall be of type 1 when the following two conditions are both true:

– the UE is not configured in MIMO mode, and

– the variable HS_DSCH_SPS_STATUS is FALSE.

HS-SCCH type 1 may be used when the following two conditions are both true:

– the UE is not configured in MIMO mode, and

– the variable HS_DSCH_SPS_STATUS is TRUE.

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

The following information, provided by higher layers, is transmitted by means of the HS-SCCH physical channel.

For 1.28 Mcps TDD, in the case of multi-frequency HS-DSCH transmission in one TTI, HS-PDSCH on each frequency shall be configured with associated HS-SCCH(s) which is coded and multiplexed as following.

– Channelisation-code-set information (q bits where q = 8 for 1.28Mcps TDD / 3.84Mcps TDD and q = 10 for 7.68Mcps TDD)): xccs,1, xccs,2, …, xccs, q

– Time slot information (n bits where n = 5 for 1.28 Mcps TDD and n = 13 for 3.84 Mcps TDD / 7.68Mcps TDD):
xts,1, xts,2, …, xts,n

– Modulation scheme information (1 bit): xms,1

– Transport-block size information (m bits where m = 6 for 1.28 Mcps TDD and m = 9 for 3.84 Mcps TDD / 7.68Mcps TDD):
xtbs,1, xtbs,2, …, xtbs,m

– Hybrid-ARQ process information (3 bits): xhap,1, xhap,2, xhap,3

– Redundancy version information (3 bits): xrv,1, xrv,2,xrv,3

– New data indicator (1 bit): xnd,1

– HS-SCCH cyclic sequence number (3 bits): xhcsn,1, xhcsn,2, xhcsn,3

– UE identity (16 bits): xue,1, xue,2, …, xue,16

For an HS-SCCH order type A for 1.28Mcps TDD,

– xccs,1, xccs,2, …, xccs, q are reserved

– xts,1, xts,2, …, xts,n shall be set to ‘00000’

– xms,1, xtbs,1, xtbs,2 shall be set to xodt,1, xodt,2, xodt,3

– xtbs,3, xtbs,4, …, xtbs,m, xhap,1, xhap,2, xhap,3 ,xrv,1, xrv,2,xrv,3 ,xnd,1, xhcsn,1, xhcsn,2, xhcsn,3 are reserved

where xodt,1, xodt,2, xodt,3 are defined in subclause 4.6A.

The following coding/multiplexing steps can be identified:

– multiplexing of HS-SCCH information (see subclause 4.6.2)

– CRC attachment (see subclause 4.6.3);

– channel coding (see subclause 4.6.4);

– rate matching (see subclause 4.6.5);

– interleaving for HS-SCCH (see subclause 4.6.6);

– mapping to physical channels (see subclauses 4.6.7 and 4.6.8).

The general coding/multiplexing flow is shown in Figure 19.

Figure 19 Coding and Multiplexing for HS-SCCH

4.6.1 HS-SCCH information field mapping

4.6.1.1 Channelisation code set information mapping

4.6.1.1.1 1.28Mcps TDD and 3.84Mcps TDD

HS-PDSCH channelisation codes are allocated contiguously from a signalled start code to a signalled stop code, and the allocation includes both the start and stop code. The start code kstart is signalled by the bits xccs,1, xccs,2, xccs,3, xccs,4 and the stop code kstop by the bits xccs,5, xccs,6, xccs,7, xccs,8. The mapping in Table 16 below applies.

Table 16: Channelisation code set information mapping for 1.28Mcps and 3.84Mcps TDD

kstart

xccs,1

xccs,2

xccs,3

xccs,4

kstop

xccs,5

xccs,6

xccs,7

xccs,8

1

0

0

0

0

1

0

0

0

0

2

0

0

0

1

2

0

0

0

1

3

0

0

1

0

3

0

0

1

0

4

0

0

1

1

4

0

0

1

1

5

0

1

0

0

5

0

1

0

0

6

0

1

0

1

6

0

1

0

1

7

0

1

1

0

7

0

1

1

0

8

0

1

1

1

8

0

1

1

1

9

1

0

0

0

9

1

0

0

0

10

1

0

0

1

10

1

0

0

1

11

1

0

1

0

11

1

0

1

0

12

1

0

1

1

12

1

0

1

1

13

1

1

0

0

13

1

1

0

0

14

1

1

0

1

14

1

1

0

1

15

1

1

1

0

15

1

1

1

0

16

1

1

1

1

16

1

1

1

1

If a value of kstart = 16 and kstop = 1 is signalled, a spreading factor of SF=1 shall be used for the HS-PDSCH resources. Other than this case, kstart > kstop shall be treated as an error by the UE.

If NON_RECTANGULAR_Resource_ ALLOCATION_STATUS is FALSE, HS-PDSCH channelization codes of all the allocated timeslots are indicated by channelisation-code-set information field.

If NON_RECTANGULAR_Resource_ ALLOCATION_STATUS is TRUE and non-rectangular resource specific timeslot set is not configured via higher layer signalling, the specific timeslot refers to the timeslot with the maximal timeslot index among all the timeslots scheduled to the UE and HS-PDSCH channelisation codes of the specific timeslot is indicated by channelisation-code set information field. The HS-PDSCH channelisation codes of timeslot 0 are signalled via higher layer signalling if timeslot 0 is scheduled to the UE. The HS-PDSCH channelisation codes of other scheduled timeslots are predefined, i.e. the entire resource of each timeslot is scheduled to the UE with SF=1.

If NON_RECTANGULAR_RESOURCE_ALLOCATION_STATUS is TRUE and non-rectangular resource specific timeslot set is configured via higher layer signalling, HS-PDSCH channelisation codes in the specific timeslot is indicated by channelisation-code set information field. The HS-PDSCH channelisation codes of other scheduled timeslots are predefined, i.e. the entire resource of the timeslot is scheduled to the UE with SF=1.

4.6.1.1.2 7.68Mcps TDD

HS-PDSCH channelisation codes are allocated contiguously from a signalled start code to a signalled stop code, and the allocation includes both the start and stop code. The start code kstart is signalled by the bits xccs,1, xccs,2, xccs,3, xccs,4, xccs,5 and the stop code kstop by the bits xccs,6, xccs,7, xccs,8, xccs,9, xccs,10. The mapping in Table 16A below applies.

Table 16A: Channelisation code set information mapping for 7.68Mcps TDD

kstart

xccs,1

xccs,2

xccs,3

xccs,4

xccs,5

kstop

xccs,6

xccs,7

xccs,8

xccs,9

xccs,10

1

0

0

0

0

0

1

0

0

0

0

0

2

0

0

0

0

1

2

0

0

0

0

1

3

0

0

0

1

0

3

0

0

0

1

0

4

0

0

0

1

1

4

0

0

0

1

1

5

0

0

1

0

0

5

0

0

1

0

0

6

0

0

1

0

1

6

0

0

1

0

1

7

0

0

1

1

0

7

0

0

1

1

0

8

0

0

1

1

1

8

0

0

1

1

1

9

0

1

0

0

0

9

0

1

0

0

0

10

0

1

0

0

1

10

0

1

0

0

1

11

0

1

0

1

0

11

0

1

0

1

0

12

0

1

0

1

1

12

0

1

0

1

1

13

0

1

1

0

0

13

0

1

1

0

0

14

0

1

1

0

1

14

0

1

1

0

1

15

0

1

1

1

0

15

0

1

1

1

0

16

0

1

1

1

1

16

0

1

1

1

1

17

1

0

0

0

0

17

1

0

0

0

0

18

1

0

0

0

1

18

1

0

0

0

1

19

1

0

0

1

0

19

1

0

0

1

0

20

1

0

0

1

1

20

1

0

0

1

1

21

1

0

1

0

0

21

1

0

1

0

0

22

1

0

1

0

1

22

1

0

1

0

1

23

1

0

1

1

0

23

1

0

1

1

0

24

1

0

1

1

1

24

1

0

1

1

1

25

1

1

0

0

0

25

1

1

0

0

0

26

1

1

0

0

1

26

1

1

0

0

1

27

1

1

0

1

0

27

1

1

0

1

0

28

1

1

0

1

1

28

1

1

0

1

1

29

1

1

1

0

0

29

1

1

1

0

0

30

1

1

1

0

1

30

1

1

1

0

1

31

1

1

1

1

0

31

1

1

1

1

0

32

1

1

1

1

1

32

1

1

1

1

1

If a value of kstart = 32 and kstop = 1 is signalled, a spreading factor of SF=1 shall be used for the HS-PDSCH resources. Other than this case, kstart > kstop shall be treated as an error by the UE.

4.6.1.2 Timeslot information mapping

4.6.1.2.1 1.28 Mcps TDD

For 1.28 Mcps, the timeslots to be used for HS-PDSCH resources are signalled by the bits xts,1, xts,2, …, xts,5, where bit xts,n carries the information for timeslot n+1. Timeslot 1 cannot be used for HS-DSCH resources. If the signalling bit is set (i.e. equal to 1), then the corresponding timeslot shall be used for HS-PDSCH resources. Otherwise, the timeslot shall not be used. If NON_RECTANGULAR_RESOURCE_ALLOCATION_STATUS is FALSE, all used timeslots shall use the same channelisation code set, as signalled by the channelisation code set information bits. Otherwise, the used timeslots may use different channelization code sets as described in 4.6.1.1.1.

When indicated by the higher layer that Timeslot 0 can be used for HS-PDSCH, bit xts,1 carries the information for timeslot 0. If xts,1 is set (i.e. equal to 1), Timeslot 0 shall be used for HS-PDSCH resource. Otherwise, Timeslot 0 shall not be used.

4.6.1.2.2 3.84 Mcps TDD and 7.68Mcps TDD

For 3.84 Mcps, the timeslots to be used for HS-PDSCH resources are signalled by the bits xts,1, xts,2, …, xts,13, where bit xts,n carries the information for the nth available timeslot for HS-PDSCH resources, where the order of the timeslots available for HS-PDSCH resources shall be the same as the order of the 15 time slots within each frame with the following two slots removed:

– The slot containing the P-CCPCH

– The first slot in a frame containing the PRACH

If the P-CCPCH and/or PRACH are assigned to some, but not all frames, then the corresponding time slots shall remain unavailable for these frames as well..

If the bit is set (i.e. equal to 1), then the corresponding timeslot shall be used for HS-PDSCH resources. Otherwise, the timeslot shall not be used. All used timeslots shall use the same channelisation code set, as signalled by the channelisation code set information bits.

4.6.1.3 Modulation scheme information mapping

The modulation scheme to be used by the HS-PDSCH resources shall be signalled by bit xms,1. If 64QAM is not supported by the UE, the mapping scheme in Table 17 shall apply.

Table 17: Modulation scheme information mapping

xms,1

Modulation Scheme

0

QPSK

1

16-QAM

If 64QAM is supported by the UE, the mapping scheme in Table 17a shall apply.

Table 17a: Modulation scheme information mapping

xms,1

Modulation Scheme

0

QPSK or 64QAM

1

16-QAM

The method of determining the modulation scheme by UE with 64QAM capability is as following:

If xms,1 = 1, then modulation scheme is 16QAM;

Else if xms,1 = 0, then

Step 1, UE first calculates the physical resource bearer capability and the transmission bit rate. The physical resource bearer capability is the maximum bit rate at which RAN can transmit with the physical resources assigned in HS-SCCH and the QPSK modulation. The physical resource bearer capability can be calculated by the channelization-code-set information and time slot information of HS-SCCH.

The transmission bit rate is the bit rate to which the transport-block size indicated in HS-SCCH corresponds.

Step 2, if the physical resource bearer capability multiplied by R is less than the transmission bit rate, and R belongs to [0, 1],

then modulation scheme is 64QAM;

else modulation scheme is QPSK.

Note: According to the simulation results the value of the transmission bit rate divided by the physical resource bearer capability according to 64QAM should be more than 1/3, where the value of R is equal to 1.

If 64QAM is configured by UE, the method of determining recommended modulation scheme by NodeB can be similar to 64QAM indication in HS-SCCH. The details are:

If xms,1 =1, NodeB should determine the recommended modulation scheme as 16QAM,

Else if xms,1 =0, NodeB calculates the physical resource bearer capability assigned in HS-SCCH corresponding to RMF and RTBS in HS-SICH, and calculates the transmission bit rate according to the RTBS in HS-SICH, and then determines whether the recommended modulation scheme is 64QAM or QPSK.

4.6.1.4 Redundancy and constellation version information mapping

The redundancy version (RV) parameters r, s and constellation version parameter b are mapped jointly to produce the value Xrv. Xrv is alternatively represented as the sequence xrv,1, xrv,2, xrv,3 where xrv,1 is the MSB. This is done according to the following tables according to the modulation mode used:

Table 18: RV mapping for 16 QAM and 64 QAM

Xrv (value)

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 19: RV mapping for QPSK

Xrv (value)

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

4.6.1.5 HS-SCCH cyclic sequence number

The HS-SCCH cyclic sequence number is mapped such that xhcsn,1 corresponds to the MSB and xhcsn,3 to the LSB.

4.6.1.6 UE identity

The UE identity is the HS-DSCH Radio Network Identifier (H-RNTI) defined in [12]. This is mapped such that xue,1 corresponds to the MSB and xue,16 to the LSB, cf. [14].

4.6.1.7 HARQ process identifier mapping

The hybrid-ARQ process information xhap,1, xhap,2, xhap,3 is unsigned binary representation of the HARQ process identifier where xhap,1 is MSB.

4.6.1.8 Transport block size index mapping

The transport-block size information xtbs,1, xtbs,2, …, xtbs,m is unsigned binary representation of the transport block size index where xtbs,1 is MSB.

4.6.2 Multiplexing of HS-SCCH information

The information carried on the HS-SCCH is multiplexed onto the bits according to the following rule :

4.6.3 CRC attachment for HS-SCCH

From the sequence of bits a 16 bit CRC is calculated according to Section 4.2.1.1. This gives a sequence of bits where

k = 1,2,…16

This latter sequence of bits is then masked with the UE identity and appended to the sequence of bits . The bits at the output of the CRC attachment block is the sequence of bits , where

i=1,2,…,A

i=A+1…B

4.6.4 Channel coding for HS-SCCH

Channel coding for the HS-SCCH shall be done with the general method described in 4.2.3 with the following specific parameters:

The rate 1/3 convolutional coding shall be used for HS-SCCH.

4.6.5 Rate matching for HS-SCCH

Rate matching for HS-SCCH shall be done with the general method described in 4.2.7.

4.6.6 Interleaving for HS-SCCH

Interleaving for HS-SCCH shall be done with the general method described in 4.2.11.1.

4.6.7 Physical Channel Segmentation for HS-SCCH

Physical channel segmentation for HS-SCCH shall be done with the general method described in 4.2.10. For 1.28 Mcps TDD, the HS-SCCH consists of two physical channels HS-SCCH1 and HS-SCCH2; for 3.84 Mcps TDD and 7.68Mcps TDD the HS-SCCH only uses one physical channel, see [7].

4.6.8 Physical channel mapping for HS-SCCH

Physical channel mapping for the HS-SCCH shall be done with the general method described in subclause 4.2.12.