4.10 Coding for E-AGCH

25.2223GPPMultiplexing and channel coding (TDD)Release 17TS

The E-AGCHs on the different carriers are coded independently.

For the 1.28 Mcps TDD, E-AGCH type 1 is used when the variable E_DCH_SPS_STATUS=FALSE and the UE is not configured in MU-MIMO mode by higher layers for a UE (as defined in [12]).

In this section, the terms "E-AGCH" and "E-AGCH type 1" are used interchangeably.

The E-AGCH carries the following fields multiplexed into w bits x_ag,1, x_ag,2, … x_ag,w. w is within the range 14 to 28 bits (for the 3.84Mcps option) and 15 to 29 bits (for the 7.68Mcps option) and 23 to 26 bits (for the 1.28Mcps option)

– Absolute grant (power) value (x_pg,1, x_pg,2, … x_pg,5) {5 bits},

– Code resource related information (x_c,1, x_c,2, … x_c,Nc), {N_c=5 bits for the 1.28Mcps and 3.84Mcps options, N_c=6 bits for the 7.68Mcps option}

– Timeslot resource related information (x_t,1, x_t,2, … x_t,nTRRI), {n_TRRI bits} [n_TRRI =5 for 1.28Mcps, and is configured by higher layers for 3.84Mcps and 7.68Mcps options]

– E-AGCH Cyclic Sequence Number (ECSN) (x_e,1, x_e,2, x_e,3) (3 bits)

– Resource duration indicator (3 bits if present) (x_r,1, x_r,2, x_r,3) – [the presence of this field is configured by higher layers]

– E-HICH Indicator (x_EI,1,x_EI,2) (2 bits) (for 1.28Mcps TDD only)

– E-UCCH Number Indicator (x_ENI,1,x_ENI,2, x_ENI,3) (3 bits) (for 1.28Mcps TDD only)

Figure 25 illustrates the overall coding chain for the E-AGCH on one carrier.

Figure 25 – TrCH processing of E-AGCH

4.10.1 Information Field Mapping

4.10.1.1 Mapping of the Absolute Grant (Power) Value

The absolute grant (power) value (x_pg,1, x_pg,2,…x_pg,5) is represented by 5 bits and corresponds to a dB value as specified in table 26 for 3.84Mcps and 7.68 Mcps TDD and in table 26A for 1.28Mcps TDD below. The values are mapped such that x_pg,1 corresponds to the MSB of the index.

Table 26: Mapping of Absolute Grant Value (for 3.84Mcps and 7.68 Mcps TDD)

Absolute Grant Value	Index
31 dB	31
30 dB	30
29 dB	29
28 dB	28
27 dB	27
26 dB	26
25 dB	25
24 dB	24
23 dB	23
22 dB	22
21 dB	21
20 dB	20
19 dB	19
18 dB	18
17 dB	17
16 dB	16
15 dB	15
14 dB	14
13 dB	13
12 dB	12
11 dB	11
10 dB	10
9 dB	9
8 dB	8
7 dB	7
6 dB	6
5 dB	5
4 dB	4
3 dB	3
2 dB	2
1 dB	1
0 dB	0

Table 26A: Mapping of Absolute Grant Value (for 1.28Mcps TDD)

Absolute Grant Value	Index
19 dB	31
18 dB	30
17 dB	29
16 dB	28
15 dB	27
14 dB	26
13 dB	25
12 dB	24
11 dB	23
10 dB	22
9 dB	21
8 dB	20
7 dB	19
6 dB	18
5 dB	17
4 dB	16
3 dB	15
2 dB	14
1 dB	13
0 dB	12
-1 dB	11
-2 dB	10
-3 dB	9
-4 dB	8
-5 dB	7
-6 dB	6
-7 dB	5
-8 dB	4
-9 dB	3
-10 dB	2
-11 dB	1
-12 dB	0

4.10.1.2 Mapping of the Code Resource Related Information

The code resource related information (x_c,1, x_c,2,…x_c,Nc) indicates which node on the OVSF code tree has been allocated and is represented by N_c bits where N_c=5 for 1.28Mcps and 3.84Mcps and N_c=6 for 7.68Mcps. The mapping between the allocated OVSF and the enumerated node 0…30 (for 1.28Mcps and 3.84Mcps) and 0…62 (for 7.68Mcps) on the OVSF code tree is as given in table 27 below, in which channelisation code "i" with spreading factor "Q" is denoted as C_i^(Q). x_c,1 corresponds to the MSB of the enumerated node. The right-most column of table 27 is only applicable for the 7.68Mcps option.

Table 27 – Channelisation code mapping

C1(1) [0]	C1(2) [1]	C1(4) [3]	C1(8) [7]	C1(16) [15]	C1(32) [31]
					C2(32) [32]
				C2(16) [16]	C3(32) [33]
					C4(32) [34]
			C2(8) [8]	C3(16) [17]	C5(32) [35]
					C6(32) [36]
				C4(16) [18]	C7(32) [37]
					C8(32) [38]
		C2(4) [4]	C3(8) [9]	C5(16) [19]	C9(32) [39]
					C10(32) [40]
				C6(16) [20]	C11(32) [41]
					C12(32) [42]
			C4(8) [10]	C7(16) [21]	C13(32) [43]
					C14(32) [44]
				C8(16) [22]	C15(32) [45]
					C16(32) [46]
	C2(2) [2]	C3(4) [5]	C5(8) [11]	C9(16) [23]	C17(32) [47]
					C18(32) [48]
				C10(16) [24]	C19(32) [49]
					C20(32) [50]
			C6(8) [12]	C11(16) [25]	C21(32) [51]
					C22(32) [52]
				C12(16) [26]	C23(32) [53]
					C24(32) [54]
		C4(4) [6]	C7(8) [13]	C13(16) [27]	C25(32) [55]
					C26(32) [56]
				C14(16) [28]	C27(32) [57]
					C28(32) [58]
			C8(8) [14]	C15(16) [29]	C29(32) [59]
					C30(32) [60]
				C16(16) [30]	C31(32) [61]
					C32(32) [62]

If NON_RECTANGULAR_RESOURCE_ALLOCATION_STATUS is FALSE, the OVSF code of all the allocated timeslots is indicated by Code Resource Related 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 closest to the timeslot in which HS-SICH and/or UL DPCH is allocated among all the uplink timeslot scheduled to the UE. The OVSF code of the specific timeslot is indicated by Code Resource Related Information field. The OVSF code of other scheduled timeslots is predefined, i.e. node 0.

If NON_RECTANGULAR_RESOURCE_ALLOCATION_STATUS is TRUE and non-rectangular resource specific timeslot set is configured via higher layer signalling, the OVSF code in the specific timeslot is indicated by Code Resource Related Information field. The OVSF code of other scheduled timeslots is predefined, i.e. node 0.

4.10.1.3 Mapping of the Timeslot Resource Related Information

For 3.84Mcsp and 7.68Mcps options, the timeslot resource related information (x_t,1, x_t,2,…x_t,nTRRI) is a bitmap of length n_TRRI indicating which of the timeslots configured for E-DCH use by higher layers have been allocated. The length of the field (n_TRRI) is configured by higher layers up to a maximum of 12 bits. The bitmap is arranged such that the corresponding timeslots are in ascending numerical order, with x_t,1 corresponding to LSB and lowest-numbered timeslot configured for E-DCH use.

For 1.28Mcps option, the timeslot resource related information (x_t,1, x_t,2,…x_t,nTRRI) is also a bitmap of length 5 indicating the allocation for E-DCH resources from TS1 to TS5. If the bit is set (i.e. equal to 1), then the corresponding timeslot shall be used for E-DCH resources. The bitmap is arranged such that the corresponding timeslots are in ascending numerical order, with x_t,1 corresponding to MSB.

4.10.1.4 Mapping of the E-AGCH Cyclic Sequence Number (ECSN)

The E-AGCH cyclic sequence number is mapped such that x_e,1 corresponds to the MSB and x_e,3 to the LSB.

4.10.1.5 Mapping of the Resource Duration Indicator

The resource duration indicator (x_r,1, x_r,2,x_r,3) is mapped such that x_r,1 corresponds to the MSB of the resource duration index described in [15].

4.10.1.6 Mapping of the E-HICH Indicator (1.28Mcps option only)

The E-HICH indicator consists of 2 bits used to indicate the UE which E-HICH will be used to convey the acknowledgement indicator in the following schedule period for 1.28Mcps TDD only. The bits (x_EI,1, x_EI,2) are mapped such that x_EI,1 corresponds to the MSB and x_EI,2 to the LSB.

4.10.1.7 Mapping of the E-UCCH Number Indicator (1.28Mcps option only)

The E-UCCH number indicator is composed of 3bits which is used to calculate the number of E-UCCH for 1.28Mcps TDD only. The bits (x_ENI,1, x_ENI,2, x_ENI,3) are mapped such that x_ENI,1 corresponds to the MSB and x_ENI,3 to the LSB. The number of the used E-UCCH is equal to ENI+1.

4.10.2 Field Multiplexing

The absolute grant (power) value, code resource related information, timeslot resource related information, resource duration indicator (if present), ECSN, E-HICH indicator (for1.28Mcps TDD only) and E-UCCH number indicator (for1.28Mcps TDD only) are multiplexed together to give a sequence of bits x_ag,1, x_ag,2, …, x_ag,w where:

For the 1.28Mcps option:

x_ag,k = x_pg,k k=1, 2, .., 5

x_ag,k = x_c,k-5 k=6, 7, …, 10

x_ag,k = x_t,k-10 k=11, …, 15

x_ag,k = x_e,k-15 k=16,17,18

if resource duration indicator (RDI) present:

x_ag,k = x_r,k-18 k=19,20,21

x_ag,k = x_EI,k-21 k=22,23

x_ag,k = x_ENI,k-23 k=24,25,26

or if resource duration indicator (RDI) does not present:

x_ag,k = x_EI,k-18 k=19,20

x_ag,k = x_ENI,k-20 k=21,22,23

For the 3.84Mcps option:

x_ag,k = x_pg,k k=1, 2, .., 5

x_ag,k = x_c,k-5 k=6, 7, …, 10

x_ag,k = x_t,k-10 k=11, …, 10+n_TRRI

x_ag,k = x_e,k-10-nTRRI k=11+n_TRRI, …, 13+n_TRRI

x_ag,k = x_r,k-13-nTRRI k=14+n_TRRI, …, 16+n_TRRI {if resource duration indicator present}

and for the 7.68Mcps option:

x_ag,k = x_pg,k k=1, 2, .., 5

x_ag,k = x_c,k-5 k=6, 7, …, 11

x_ag,k = x_t,k-11 k=12, …, 11+n_TRRI

x_ag,k = x_e,k-11-nTRRI k=12+n_TRRI, …, 14+n_TRRI

x_ag,k = x_r,k-14-nTRRI k=15+n_TRRI, …, 17+n_TRRI {if resource duration indicator present}

4.10.3 CRC attachment

The E-RNTI (x_id,1, x_id,2, …, x_id,16) is the E‑DCH Radio Network Identifier defined in [12]. It is mapped such that x_id,1 corresponds to the MSB.

From the sequence of bits x_ag,1, x_ag,2, …, x_ag,w a 16 bit CRC is calculated according to section 4.2.1.1. This gives the sequence of bits c₁, c₂, …, c₁₆ where:

k=1,2,…,16

This sequence of bits is then masked with x_id,1, x_id,2, …, x_id,16 and appended to the sequence of bits x_ag,1, x_ag,2, …, x_ag,w to form the sequence of bits y₁, y₂, …, y_w+16 where

y_i=x_ag,i i=1,2, …,w

y_i=(c_i-w + x_id,_i-w) mod 2 i=w+1, …, w+16

4.10.4 Channel Coding

1/3 rate convolutional channel coding is applied to the sequence y₁, y₂,…, y_w+16 in accordance with section 4.2.3.1, resulting in the sequence of bits z₁, z₂, …, z_3(w+24).

4.10.5 Rate Matching

Rate matching is applied to the input sequence z₁, z₂, …, z_3(w+24) to obtain the output sequence r₁, r₂, …, r_U, where U = 242 for burst type 1 and U = 274 for burst type 2 for 3.84Mcps and 7.68Mcps options while U=172 for 1.28Mcps option.

4.10.6 Interleaving

Interleaving is performed as per section 4.2.11.1 (frame-related 2^nd interleaving).

4.10.7 Physical Channel Segmentation

Physical channel segmentation is performed as per section 4.2.10. For 1.28Mcps TDD, the E-AGCH consists of two physical channels E-AGCH1 and E-AGCH2,whereas for 3.84Mcps and 7.68Mcps TDD the E-AGCH only uses one physical channel, see[7].Note that physical channel segmentation is transparent when only one physical channel exists

4.10.8 Physical Channel Mapping

Physical channel mapping is performed as per section 4.2.12.