4.10 Coding for E‑AGCH

25.2123GPPMultiplexing and channel coding (FDD)Release 17TS

The following information is transmitted by means of the absolute grant channel (E‑AGCH):

– Absolute Grant Value: x_agv,1, x_agv,2, …, x_agv,5

– Absolute Grant Scope: x_ags,1

4.10.1 Overview

Figure 24 below illustrates the overall coding chain for the E‑AGCH.

Figure 24: Coding for E‑AGCH

4.10.1A E-AGCH information field mapping

4.10.1A.1 Information field mapping of the Absolute Grant Value

The Absolute Grant Value information is specified in Table 16B and Table 16.B.1. The values are mapped such that x_agv,1 corresponds to the MSB of the index.

Based on higher layer signalling, either Table 16B or Table 16.B.1 is selected.

Table 16B: Mapping of Absolute Grant Value

Absolute Grant Value	Index
(168/15)2x6	31
(150/15)2x6	30
(168/15)2x4	29
(150/15)2x4	28
(134/15)2x4	27
(119/15)2x4	26
(150/15)2x2	25
(95/15)2x4	24
(168/15)2	23
(150/15)2	22
(134/15)2	21
(119/15)2	20
(106/15)2	19
(95/15)2	18
(84/15)2	17
(75/15)2	16
(67/15)2	15
(60/15)2	14
(53/15)2	13
(47/15)2	12
(42/15)2	11
(38/15)2	10
(34/15)2	9
(30/15)2	8
(27/15)2	7
(24/15)2	6
(19/15)2	5
(15/15)2	4
(11/15)2	3
(7/15)2	2
ZERO_GRANT*	1
INACTIVE*	0

NOTE *: These values are specified in [16].

Table 16B.1: Alternative Mapping of Absolute Grant Value

Absolute Grant Value	Index
(377/15)2x4	31
(237/15)2x6	30
(168/15)2*6	29
(150/15)2*6	28
(168/15)2*4	27
(150/15)2x4	26
(134/15)2x4	25
(119/15)2x4	24
(150/15)2x2	23
(95/15)2x4	22
(168/15)2	21
(150/15)2	20
(134/15)2	19
(119/15)2	18
(106/15)2	17
(95/15)2	16
(84/15)2	15
(75/15)2	14
(67/15)2	13
(60/15)2	12
(53/15)2	11
(47/15)2	10
(42/15)2	9
(38/15)2	8
(34/15)2	7
(30/15)2	6
(27/15)2	5
(24/15)2	4
(19/15)2	3
(15/15)2	2
ZERO_GRANT*	1
INACTIVE*	0

NOTE *: These values are specified in [16].

4.10.1A.2 Information field mapping of the Absolute Grant Scope

The value of x_ags,1 is set as specified in Table 16C.

Table 16C: Mapping of Absolute Grant Scope

Absolute Grant Scope	xags,1
"Per HARQ process"	1
"All HARQ processes"	0

4.10.1B Multiplexing of E-AGCH information

The Absolute Grant Value information x_agv,1, x_agv,2, …, x_agv,5 and the Absolute Grant Scope information x_ags,1 are multiplexed together. This gives a sequence of bits x_ag,1, x_ag,2, …, x_{ag, 6} where

x_ag,k = x_agv,k k=1,2,…,5

x_ag,k = x_ags,7-k k=6

4.10.2 CRC attachment for E‑AGCH

The E-RNTI is the E‑DCH Radio Network Identifier defined in [13]. 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,6 a 16 bit CRC is calculated according to clause 4.2.1.1. That 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,6 to form the sequence of bits y₁, y₂, …, y₂₂ where

y_i=x_ag,i i=1,2, …,6

y_i=(c_i-6 + x_id,_i-6) mod 2 i= 7, …, 22

4.10.3 Channel coding for E‑AGCH

Rate 1/3 convolutional coding, as described in Clause 4.2.3.1 is applied to the sequence of bits y₁, y₂, …, y₂₂, resulting in the sequence of bits z₁, z₂, …, z₉₀.

4.10.4 Rate matching for E‑AGCH

From the input sequence z₁, z₂, …, z₉₀ the bits z₁, z₂, z₅, z₆, z₇, z₁₁, z₁₂, z₁₄, z₁₅, z₁₇, z₂₃, z₂₄, z₃₁, z₃₇, z₄₄, z₄₇, z₆₁, z₆₃, z₆₄, z₇₁, z₇₂, z₇₅, z₇₇, z₈₀, z₈₃, z₈₄, z₈₅, z₈₇, z₈₈, z₉₀ are punctured to obtain the output sequence r₁, r₂, …, r₆₀.

4.10.5 Physical channel mapping for E‑AGCH

The E‑AGCH sub frame is described in [2]. The sequence of bits r₁, r₂, …, r₆₀ is mapped to the corresponding E‑AGCH sub frame. The bits r_k are mapped so that they are transmitted over the air in ascending order with respect to k. If the E‑DCH TTI is equal to 10 ms the same sequence of bits is transmitted in all the E‑AGCH sub frames of the E‑AGCH radio frame.