3 Frame Structure

08.603GPPIn-band control of remote transcoders and rate adaptors for Enhanced Full Rate (EFR) and full rate traffic channelsTS

3.1 Frames for Speech Services

3.1.1 Frames for Full Rate and Enhanced Full Rate Speech

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

C14

C15

4

1

D1

D2

D3

D4

D5

D6

D7

5

D8

D9

D10

D11

D12

D13

D14

D15

6

1

D16

D17

D18

D19

D20

D21

D22

7

D23

D24

D25

D26

D27

D28

D29

D30

8

1

D31

D32

D33

D34

D35

D36

D37

9

D38

D39

D40

D41

D42

D43

D44

D45

10

1

D46

D47

D48

D49

D50

D51

D52

11

D53

D54

D55

D56

D57

D58

D59

D60

12

1

D61

D62

D63

D64

D65

D66

D67

13

D68

D69

D70

D71

D72

D73

D74

D75

14

1

D76

D77

D78

D79

D80

D81

D82

15

D83

D84

D85

D86

D87

D88

D89

D90

16

1

D91

D92

D93

D94

D95

D96

D97

17

D98

D99

D100

D101

D102

D103

D104

D105

18

1

D106

D107

D108

D109

D110

D111

D112

19

D113

D114

D115

D116

D117

D118

D119

D120

20

1

D121

D122

D123

D124

D125

D126

D127

21

D128

D129

D130

D131

D132

D133

D134

D135

22

1

D136

D137

D138

D139

D140

D141

D142

23

D143

D144

D145

D146

D147

D148

D149

D150

24

1

D151

D152

D153

D154

D155

D156

D157

25

D158

D159

D160

D161

D162

D163

D164

D165

26

1

D166

D167

D168

D169

D170

D171

D172

27

D173

D174

D175

D176

D177

D178

D179

D180

28

1

D181

D182

D183

D184

D185

D186

D187

29

D188

D189

D190

D191

D192

D193

D194

D195

30

1

D196

D197

D198

D199

D200

D201

D202

31

D203

D204

D205

D206

D207

D208

D209

D210

32

1

D211

D212

D213

D214

D215

D216

D217

33

D218

D219

D220

D221

D222

D223

D224

D225

34

1

D226

D227

D228

D229

D230

D231

D232

35

D233

D234

D235

D236

D237

D238

D239

D240

36

1

D241

D242

D243

D244

D245

D246

D247

37

D248

D249

D250

D251

D252

D253

D254

D255

38

1

D256

D257

D258

D259

D260

C16

C17

39

C18

C19

C20

C21

T1

T2

T3

T4

3.1.2 Frames for Adaptive Multi-Rate Speech

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

C14

C15

4

1

C16

C17

C18

C19

C20

C21

C22

5

C23

C24

C25

D1

D2

D3

D4

D5

6

1

D6

D7

D8

D9

D10

D11

D12

7

D13

D14

D15

D16

D17

D18

D19

D20

8

1

D21

D22

D23

D24

D25

D26

D27

9

D28

D29

D30

D31

D32

D33

D34

D35

10

1

D36

D37

D38

D39

D40

D41

D42

11

D43

D44

D45

D46

D47

D48

D49

D50

12

1

D52

D52

D53

D54

D55

D56

D57

13

D58

D59

D60

D61

D62

D63

D64

D65

14

1

D66

D67

D68

D69

D70

D71

D72

15

D73

D74

D75

D76

D77

D78

D79

D80

16

1

D81

D82

D83

D84

D85

D86

D87

17

D88

D89

D90

D91

D92

D93

D94

D95

18

1

D96

D97

D98

D99

D100

D101

D102

19

D103

D104

D105

D106

D107

D108

D109

D110

20

1

D111

D112

D113

D114

D115

D116

D117

21

D118

D119

D120

D121

D122

D123

D124

D125

22

1

D126

D127

D128

D129

D130

D131

D132

23

D133

D134

D135

D136

D137

D138

D139

D140

24

1

D141

D142

D143

D144

D145

D146

D147

25

D148

D149

D150

D151

D152

D153

D154

D155

26

1

D156

D157

D158

D159

D160

D161

D162

27

D163

D164

D165

D166

D167

D168

D169

D170

28

1

D171

D172

D173

D174

D175

D176

D177

29

D178

D179

D180

D181

D182

D183

D184

D185

30

1

D186

D187

D188

D189

D190

D191

D192

31

D193

D194

D195

D196

D197

D198

D199

D200

32

1

D201

D202

D203

D204

D205

D206

D207

33

D208

D209

D210

D211

D212

D213

D214

D215

34

1

D216

D217

D218

D219

D220

D221

D222

35

D223

D224

D225

D226

D227

D228

D229

D230

36

1

D231

D232

D233

D234

D235

D236

D237

37

D238

D239

D240

D241

D242

D243

D244

D245

38

1

D246

D247

D248

D249

D250

D251

D252

39

D253

D254

D255

D256

T1

T2

T3

T4

3.2 O&M Frames

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

C14

C15

4

1

D1

D2

D3

D4

D5

D6

D7

5

D8

D9

D10

D11

D12

D13

D14

D15

6

1

D16

D17

D18

D19

D20

D21

D22

7

D23

D24

D25

D26

D27

D28

D29

D30

8

1

D31

D32

D33

D34

D35

D36

D37

9

D38

D39

D40

D41

D42

D43

D44

D45

10

1

D46

D47

D48

D49

D50

D51

D52

11

D53

D54

D55

D56

D57

D58

D59

D60

12

1

D61

D62

D63

D64

D65

D66

D67

13

D68

D69

D70

D71

D72

D73

D74

D75

14

1

D76

D77

D78

D79

D80

D81

D82

15

D83

D84

D85

D86

D87

D88

D89

D90

16

1

D91

D92

D93

D94

D95

D96

D97

17

D98

D99

D100

D101

D102

D103

D104

D105

18

1

D106

D107

D108

D109

D110

D111

D112

19

D113

D114

D115

D116

D117

D118

D119

D120

20

1

D121

D122

D123

D124

D125

D126

D127

21

D128

D129

D130

D131

D132

D133

D134

D135

22

1

D136

D137

D138

D139

D140

D141

D142

23

D143

D144

D145

D146

D147

D148

D149

D150

24

1

D151

D152

D153

D154

D155

D156

D157

25

D158

D159

D160

D161

D162

D163

D164

D165

26

1

D166

D167

D168

D169

D170

D171

D172

27

D173

D174

D175

D176

D177

D178

D179

D180

28

1

D181

D182

D183

D184

D185

D186

D187

29

D188

D189

D190

D191

D192

D193

D194

D195

30

1

D196

D197

D198

D199

D200

D201

D202

31

D203

D204

D205

D206

D207

D208

D209

D210

32

1

D211

D212

D213

D214

D215

D216

D217

33

D218

D219

D220

D221

D222

D223

D224

D225

34

1

D226

D227

D228

D229

D230

D231

D232

35

D233

D234

D235

D236

D237

D238

D239

D240

36

1

D241

D242

D243

D244

D245

D246

D247

37

D248

D249

D250

D251

D252

D253

D254

D255

38

1

D256

D257

D258

D259

D260

D261

D262

39

D263

D264

S1

S2

S3

S4

S5

S6

3.3 Data Frames

3.3.1 Data Frame (for Synchronisation)

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

C14

C15

4

1

.

5

1

.

6

1

.

7

1

Data frame position 1

8

1

63 bits.

9

1

(72 bits including bit position 1)

10

1

11

1

12

1

13

1

14

1

15

1

161

1

Data frame position 2

17

1

18

1

19

1

20

1

21

1

22

1

23

1

24

1

25

1

Data frame position 3

26

1

27

1

28

1

29

1

30

1

31

1

32

1

33

1

Data frame position 4

34

1

35

1

36

1

37

1

38

1

39

1

3.3.2 Extended data frame (E-TRAU : data transport)

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

M1

M2

4

D1

D2

5

6

7

Data block of 288 data bits and M1, M2.

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

D287

D288

3.4 Idle Speech Frames

Bit number

Octet no.

1

2

3

4

5

6

7

8

0

0

0

0

0

0

0

0

0

1

0

0

0

0

0

0

0

0

2

1

C1

C2

C3

C4

C5

C6

C7

3

C8

C9

C10

C11

C12

C13

C14

C15

4

1

1

1

1

1

1

1

1

5

1

1

1

1

1

1

1

1

6

1

1

1

1

1

1

1

1

7

1

1

1

1

1

1

1

1

8

1

1

1

1

1

1

1

1

9

1

1

1

1

1

1

1

1

10

1

1

1

1

1

1

1

1

11

1

1

1

1

1

1

1

1

12

1

1

1

1

1

1

1

1

13

1

1

1

1

1

1

1

1

14

1

1

1

1

1

1

1

1

15

1

1

1

1

1

1

1

1

16

1

1

1

1

1

1

1

1

17

1

1

1

1

1

1

1

1

18

1

1

1

1

1

1

1

1

19

1

1

1

1

1

1

1

1

20

1

1

1

1

1

1

1

1

21

1

1

1

1

1

1

1

1

22

1

1

1

1

1

1

1

1

23

1

1

1

1

1

1

1

1

24

1

1

1

1

1

1

1

1

25

1

1

1

1

1

1

1

1

26

1

1

1

1

1

1

1

1

27

1

1

1

1

1

1

1

1

28

1

1

1

1

1

1

1

1

29

1

1

1

1

1

1

1

1

30

1

1

1

1

1

1

1

1

31

1

1

1

1

1

1

1

1

32

1

1

1

1

1

1

1

1

33

1

1

1

1

1

1

1

1

34

1

1

1

1

1

1

1

1

35

1

1

1

1

1

1

1

1

36

1

1

1

1

1

1

1

1

37

1

1

1

1

1

1

1

1

38

1

1

1

1

1

1

C16

C17

39

C18

C19

C20

C21

T1

T2

T3

T4

3.5 Coding

In the following clauses, the coding of the frames is described. Any spare or not used control bits should be coded binary "1".

For all frame types the octet 0, 1 and the first bit of octets 2, 4, 6, 8, … 38 are used as frame sync.

3.5.1 Coding of Frames for Speech Services

3.5.1.1 Coding of Frames for Full Rate and Enhanced Full Rate Speech

3.5.1.1.1 Coding of Control bits (C-bits)

Description

Uplink

Downlink

C1C2C3C4 C5

C1C2C3C4 C5

Frame type FR

Speech:  0  0  0  1  0.

Speech:  1  1  1  0  0

(Bits C1 – C5). EFR

Speech:  1  1  0  1  0

Speech:  1  1  0  1  0

Time

Binary number indicating the

Binary number indicating

Alignment

required timing adjustment to

the timing adjustment made.

(Bits C6 – C11)

be made in steps of 250/500 s.

The following values apply for the coding

C6C7   . . .    C11

0  0  0  0  0  0  No change in frame timing

0  0  0  0  0  1  Delay frame 1 x 500 s

0  0  0  0  1  0  Delay frame 2 x 500 s

           .   .   .  ….

           .   .   .  ….

1  0  0  1  1  1  Delay frame 39 x 500 s

1  0  1  0  0  0  Not used

           .   .   .  ….

1  1  1  1  0  1  Not used

1  1  1  1  1  0  Delay frame 1 x 250 s

1  1  1  1  1  1  Advance frame 250 s

Frame indicators. The definition

C12: BFI

C12 – C15: Spare

and coding of these indicators

0  : BFI = 0

are given in GSM 06.31.

1  : BFI = 1

IF FR. Speech

C13 C14: SID

ELSE

Bits C12 – C16

 0     0  :SID = 0

C12: UFE

 0     1  :SID = 1

0  :UFE=0 bad uplink frame

 1     0  :SID = 2

1  :  UFE=1 good up-link frame

Downlink

 

Uplink Frame Error

C15:  TAF

(UFE) C12

 0  :  TAF = 0

(see clause 4.8.3)

 1  :  TAF = 1

C13 – C15: spare

C16: Spare

C16: SP

 0  :  SP = 0

 1  :  SP = 1

DTX indicator

C17: DTXd

C17: Spare

0  :  DTX not applied

1  :  DTX applied

Bits C18 – C21

Spare

Spare

3.5.1.1.2 Coding of Data Bits (D-bits)

For Full Rate Speech:

Bits D1 .. D260: Speech block transferred in the same order as output from the transcoder (see GSM 06.10).

For Enhanced Full Rate Speech:

The speech block is subdivided in five subsets. The order within a given subset is the same as output from the transcoder (see ETS 300 726, GSM 06.60). Three parity bits are added at the end of each sub-set.

These parity bits are added to the bits of the subset, according to a degenerate (shortened) cyclic code using the generator polynomial:

g(D) = D3 + D + 1

The encoding of the cyclic code is performed in a systematic form which means that, in GF(2), the polynomial:

d(m)Dn + d(m+1)Dn‑1 + ……+ d(m + n‑3)D3 + p(0)D2 + p(1)D + p(2)

where p(0), p(1), p(2) are the parity bits, when divided by g(D), yields a remainder equal to:

1 + D + D2

For every CRC, the transmission order is p(0) first followed by p(1) and p(2) successively.

Bit D1 : spare (binary "1").

Bits D2…D39 : Indexes of the LSF submatrices.

Bits D40…D42 : CRC over bits D1 to D22, D25 to D27 and D29.

Bits D43…D95 : Indexes of the parameters of first sub-frame.

Bits D96…D98 : CRC over bits D43 to D52, D91 and D92.

Bits D99…D148 : Indexes of the parameters of second sub-frame.

Bits D149…D151 : CRC over bits D99 to D103, D105, D144 and D145.

Bits D152…D204 : Indexes of the parameters of third sub-frame.

Bits D205…D207 : CRC over bits D152 to D161, D200 and D201.

Bits D208…D257 : Indexes of the parameters of fourth sub-frame.

Bits D258…D260 : CRC over bits D208 to D212, D214, D253 and D254.

3.5.1.1.3 Time Alignment Bits (T1…T4)

Bits T1 .. T4: Bits positioned at the end of the downlink frames. If the timing of the frame is to be advanced 250 µs, these 4 bits are not transferred in order to reduce the frame length accordingly. When transferred the bits are set to binary "1".

3.5.1.2 Coding of Frames for Adaptive Multi-Rate Speech

3.5.1.2.1 Coding of Control bits (C-bits)

Control Bits

Description Uplink

Description Downlink

C1…C5

Frame_Type (Codec_Type)

Frame_Type (Codec_Type)

C6…C11

Time Alignment Command (TAC) or Phase Alignment Control (PAC) or
TFO Information or
Handover Information

Time Alignment Command (TAC) or
Phase Alignment Control (PAC) or
TFO Information or
Handover Information

C12

Request or Indication Flag (RIF)

Request or Indication Flag (RIF)

C13

spare, set to 1

Uplink Frame Error (UFE)

C14 . C15 . C16

Config_Prot

Config_Prot

C17 . C18

Message_No

Message_No

C19

DTX in downlink requested (DTXd)

spare, reserved for TFO (see 08.62)

C20

TFO Enabled (TFOE)

spare, reserved for TFO (see 08.62)

C21 . C22

Frame_Classification, Rx_Type

Frame_Classification, Tx_Type

C23 . C24 . C25

Codec_Mode_Indication (RIF == 0) or
Codec_Mode_Request (RIF == 1) or
0.0.0 (Frame_Classification == 0.0)

Codec_Mode_Indication (RIF == 0) or
Codec_Mode_Request (RIF == 1) or
0.0.0 (Frame_Classification == 0.0)

Detailed Description:

Frame Type:
The coding of the Frame_Type (also called "Codec_Type") for AMR is identical in uplink and downlink.
C1…C5:
0.0.1.1.0: Adaptive Multi-Rate Codec.

Time Alignment Field:
The Time Alignment Field (Bits C6…C11) is used to carry either the Time Alignment Command (TAC), the Phase Alignment Control (PAC) or the TFO and Handover Information. The Time Alignment Command is coded as for the Full Rate and Enhanced Full Rate (clause 3.5.1.1.1).

Time Alignment Command (TAC):
In the uplink direction (BTS to TRAU) the TAC indicates the required timing adjustment for the downlink TRAU frame to be made by the TRAU in 250/500ms steps.
C6…C11:
0.0.0.0.0.0 No change in frame timing
0.0.0.0.0.1 Delay frame 1 x 500ms (send four additional T-Bit-pairs after the end of the TRAU Frame)
0.0.0.0.1.0 Delay frame 2 x 500ms (send eight additional T-Bit-pairs after the end of the TRAU Frame)

1.0.0.1.1.1 Delay frame 39 x 500ms (send 156 additional T-Bit-pairs after the end of the TRAU Frame)
(1.0.1.0.0.0 to 1.1.0.1.1.1: 16 code-points, unused, reserved)
(1.1.1.0.0.0 to 1.1.1.0.1.1: 4 code-points, reserved for TFO and Handover Information)
(1.1.1.1.0.0 reserved for Handover Information)
(1.1.1.1.0.1 reserved for AMR CMI/CMR Phase Alignment Command (PAC), no change in frame timing)
1.1.1.1.1.0 Delay frame by 250ms (send two additional T-Bit-pairs after the end of the TRAU Frame)
1.1.1.1.1.1 Advance frame by 250ms (do not send the two T-Bit-pairs at the end of the TRAU Frame).

Phase Alignment Command (PAC) (useful when TFO is not supported or disabled):
The Phase Alignment Command (PAC) can be used by the BTS to command the TRAU to change (invert) the phase of CMI/CMR, respectively RIF, in downlink TRAU frames, see clause 4.6.1.2.1.
C6…C11:
1.1.1.1.0.1 AMR CMI/CMR Phase Alignment Command (PAC), no change in frame timing.

In No_Speech frames the Phase Alignment Command may optionally be transmitted by one additional bit (PAB, see subclause 3.5.1.2.2) that allows a direct time and phase alignment in one step.

TFO Information (recommended when TFO is supported, see GSM 08.62):
C6…C11
1.1.1.0.0.0
1.1.1.0.0.1
1.1.1.0.1.0
These three codes are reserved for Tandem Free Operation (see GSM 08.62). They result in no change in frame timing. If the BTS does not support TFO or TFO is disabled these codes shall not be used. The procedure to exchange this information between BTS and TRAU is described in GSM 08.62.

Handover Information (recommended when Pre-Handover Warning is supported):
C6…C11:
1.1.1.0.1.1 Handover_Soon Handover is to be expected soon.

1.1.1.1.0.0 Handover_Complete
These codes are used, if the BSC and BTS support Pre-Handover Warning. They result in no change in frame timing. The BTS shall repeat this information as long as it is valid in every frame where no other information has to be transmitted in the Time Alignment Field. The TRAU shall not reflect or acknowledge it. The procedure to exchange this information in case of TFO is described in GSM 08.62.

Request or Indication Flag (RIF):
This flag indicates the phase of the Codec_Mode_Indication (RIF == 0) respectively the Codec_Mode_Request (RIF == 1). It has the same meaning in uplink and in downlink. Typically this flag toggles every frame. Exceptions may occur at handover and CMI/CMR phase alignment, see clause 4.6.1.2.1.

Uplink Frame Error (UFE):
In downlink the UFE indicates that the most recently received uplink TRAU frame had detectable errors.
In uplink this bit shall be set to "1".
UFE == 0: "Uplink Frame received with Errors";
UFE == 1: "Uplink Frame received without Errors".
Note: the UFE is not related to the frame classification (Rx_Type) as computed by the BTS radio receiver. It is related to inconsistencies in the TRAU frame synchronization, control bits or CRCs within the TRAU frame.

Config_Prot
This field is reserved for the Configuration Protocol in case of Tandem Free Operation (see GSM 08.62). If the BTS does not support TFO or TFO is disabled, then this field shall be set to "0.0.0".

Message_No
This field is reserved for the Configuration Protocol in case of Tandem Free Operation (see GSM 08.62). If the BTS does not support TFO or TFO is disabled, then this field shall be set to "0.0".

DTX in downlink requested (DTXd)
See clause 4.6.2.2.

TFO Enabled (TFOE)
This bit enables or disables Tandem Free Operation in the TRAU. If the BTS does not support TFO or TFO is disabled, then this bit shall be set to "0". Coding:
TFOE == 0: TFO Disabled;
TFOE == 1: TFO Enabled.

Frame_Classification:
This field classifies the contents of the TRAU frame as seen by the radio receiver, see GSM 06.93:
C21…C22:
1 1 "Speech_Good" the frame can be decoded without restriction
1 0 "Speech_Degraded" the frame might contain undetected errors
0 1 "Speech_Bad" the frame contains errors that can not be corrected
0 0 "No_Speech" the frame is not a speech frame, see below.

In the uplink direction the Frame_Classification is also called "Rx_Type" and is always set by the BTS.

In the downlink direction the Frame_Classification is also called "Tx_Type".
If Tandem Free Operation is not ongoing, then the codes "Speech_Degraded", and "Speech_Bad" shall not be used in the downlink direction. If Tandem Free Operation is ongoing, then all codes may be used in the downlink direction. For the handling within the downlink BTS, see GSM 08.62).

Codec_Mode_Indication / Codec_Mode_Request:
This 3-bit field has three different meanings, depending on the Frame_Classification field and the Request_or_Indication_Flag (RIF):
If Frame_Classification is different than "0.0" then this field contains
either the Codec_Mode_Indication (CMI), if RIF equals 0;
or the Codec_Mode_Request (CMR), if RIF equals 1.
If Frame_Classification is equal to "0.0", i.e. when a No_Speech frame is transmitted, then this field shall be set to "0.0.0". CMI and CMR are then simultaneously transmitted in the Data Bits.
The coding is identical in uplink and downlink.
C23 . C24. C25:
0 0 0 Codec_Mode 4,75 kBit/s
0 0 1 Codec_Mode 5,15 kBit/s
0 1 0 Codec_Mode 5,90 kBit/s
0 1 1 Codec_Mode 6,70 kBit/s
1 0 0 Codec_Mode 7,40 kBit/s
1 0 1 Codec_Mode 7,95 kBit/s
1 1 0 Codec_Mode 10,2 kBit/s
1 1 1 Codec_Mode 12,2 kBit/s
The CMI indicates the Codec_Mode to be used for decoding the associated speech parameters in the same and the next frame. The CMR indicates the Codec_Mode to be used for encoding in the opposite direction.

NOTE 1: In the TRAU frames, the Codec_Mode_Request, respectively the Codec_Mode_Indication are coded absolutely (three bits for eight possible modes). On the radio interface, because of bandwidth limitation, these parameters are coded with two bits only. The CCU shall perform the required translation.

NOTE 2: In case of no Tandem Free Operation the uplink CMR is a Codec_Mode_Command (CMC) from the BTS to the TRAU and the TRAU shall try to follow the command as soon as possible. The only allowed exception is in case of DTX when SID or No_Data frames can be used during speech pauses. In the downlink direction the CMR shall be set by the TRAU to "1.1.1".

NOTE 3: In case of an ongoing Tandem Free Operation, the local uplink CMR is an indication from the local BTS to the TRAU, respectively to the distant BTS, on the highest allowed Codec_Mode in the local downlink direction. This indication must be combined with the corresponding CMR in the distant uplink direction to set the Codec Mode to use in that direction. The local downlink CMR is the indication from the distant radio link on the highest allowed Codec_Mode in the distant downlink direction. This indication must be combined with the corresponding CMR for the local uplink direction, see GSM 05.09 and 08.62.

3.5.1.2.2 Coding of Data bits (D-bits)

In Codec_Mode 10,2 kBit/s the bits D1…D20 and D234…D253 are reserved for Tandem Free Operation In all Codec_Modes below 10,2 kBit/s and in all No_Speech frames the bits D1…D31 (31 bits) and D203…D256 (54 bits) are reserved for Tandem Free Operation (see GSM 08.62).
In No_Speech frames additionally bits D44…D57 (14 bits) are reserved for TFO as well.

If the BTS does not support TFO or TFO is disabled, then the bits in these fields shall all be set to "1".

Coding of Speech Frames:
The contents of the Data bits for all eight AMR Codec_Modes are defined in the following, in cases when the Frame_Classification is either set to Speech_Good, Speech_Degraded, or Speech_Bad. The speech block is subdivided into four subsets. The order within a given subset is the same as output from the transcoder (see GSM 06.90). The four times three parity bits (CRC1 to CRC4), added at the end of each subset, are generated using the same cyclic code as defined for the Enhanced Full Rate (see clause 3.5.1.1.2). The TRAU frame formats in uplink and downlink direction are identical.

AMR_Mode 12,2 kBit/s, see GSM 06.90:
D1…D38: Indexes of the LSF submatrices (s1…s38)
D39…D91: Indexes of the parameters of first sub-frame (s39…s91)
D92…D94: CRC1 over bits C1…C25, s1…s29, s39…s50, s87…s89.
D95…D144: Indexes of the parameters of second sub-frame (s92…s141)
D145…D147: CRC2 over bits s92…s100, s137…s139.
D148…D200: Indexes of the parameters of third sub-frame (s142…s194)
D201…D203: CRC3 over bits s142…s153, s190…s192.
D204…D253: Indexes of the parameters of fourth sub-frame (s195….s244)
D254…D256: CRC4 over bits s195…s199, s201…s203, s240…s242.

AMR_Mode 10,2 kBit/s, see GSM 06.90:
D21…D46: Indexes of the LSF submatrices (s1…s26)
D47…D92: Indexes of the parameters of first sub-frame (s27…s72)
D93…D95: CRC1 over bits C1…C25, D1…D20, s1…s25, s27…s34, s66, s67, s69, s70.
D96…D138: Indexes of the parameters of second sub-frame (s73…s115)
D139…D141: CRC2 over bits s73…s76, s109, s110, s112, s113.
D142…D187: Indexes of the parameters of third sub-frame (s116…s161)
D188…D190: CRC3 over bits s116…s123, s155, s156, s158, s159.
D191…D233: Indexes of the parameters of fourth sub-frame (s162…s204)
D254…D256: CRC4 over bits s162…s165, s198, s199, s201, s202, D234…D253.

AMR_Mode 7,95 kBit/s, see GSM 06.90:
D32…D58: Indexes of the LSF submatrices (s1…s27)
D59…D92: Indexes of the parameters of first sub-frame (s28…s61)
D93…D95: CRC1 over bits C1…C25, s1…s35, s53, s54, s57, s60.
D96…D127: Indexes of the parameters of second sub-frame (s62…s93)
D128…D130: CRC2 over bits s62…s65, s85, s86, s89…s92.
D131…D164: Indexes of the parameters of third sub-frame (s94…s127)
D165…D167: CRC3 over bits s94…s101, s119, s120, s123…s126.
D168…D199: Indexes of the parameters of fourth sub-frame (s128…s159)
D200…D202: CRC4 over bits s128…s131, s151, s152, s155…s158.

AMR_Mode 7,40 kBit/s, see GSM 06.90:
D32…34 spare (3 bits); set to "1"
D35…D60: Indexes of the LSF submatrices (s1…s26)
D61…D92: Indexes of the parameters of first sub-frame (s27…s58)
D93…D95: CRC1: bits C1…C25, s1…s20, s22…s24, s27…s32, s52, s53, s55…s57.
D96…D124: Indexes of the parameters of second sub-frame (s59…s87)
D125…D127: CRC2 over bits s59…s61, s81, s82, s84…s86.
D128…D159: Indexes of the parameters of third sub-frame (s88…s119)
D160…D162: CRC3 over bits s88…s93, s113, s114, s116…s118.
D163…D191: Indexes of the parameters of fourth sub-frame (s120…s148)
D192…D194: CRC4 over bits s120…s122, s142, s143, s145, s146.
D195…D202: spare (8 bits); set to "1".

AMR_Mode 6,70 kBit/s, see GSM 06.90:
D32…D37: spare (6 bits); set to "1"
D38…D63: Indexes of the LSF submatrices (s1…s26)
D64…D92: Indexes of the parameters of first sub-frame (s27…s55)
D93…D95: CRC1 over bits C1…C25, s1…s17, s20, s24, s27…s34, s49…s53.
D96…D120: Indexes of the parameters of second sub-frame (s56…s80)
D121…D123: CRC2 over bits s56…s59, s74…s78.
D124…D152: Indexes of the parameters of third sub-frame (s81…s109)
D153…D155: CRC3 over bits s81…s88, s103…s107.
D156…D180: Indexes of the parameters of fourth sub-frame (s110…s134)
D181…D183: CRC4 over bits s110…s113, s128…s132.
D184…D202: spare (19 bits); set to "1".

AMR_Mode 5,90 kBit/s, see GSM 06.90:
D32…D41: spare (10 bits); set to "1"
D42…D67: Indexes of the LSF submatrices (s1…s26)
D68…D92: Indexes of the parameters of first sub-frame (s27…s51)
D93…D95: CRC1 over bits C1…C25, s1…s17, s27…s34, s48…s51.
D96…D116: Indexes of the parameters of second sub-frame (s52…s72)
D117…D119: CRC2 over bits s52…s54, s69…s72.
D120…D144: Indexes of the parameters of third sub-frame (s73…s97)
D145…D147: CRC3 over bits s73…s80, s94…s97.
D148…D168: Indexes of the parameters of fourth sub-frame (s98…s118)
D169…D171: CRC4 over bits s98…s100, s115…s118.
D172…D202: spare (31 bits); set to "1".

AMR_Mode 5,15 kBit/s, see GSM 06.90:
D32…D46 spare (15 bits); set to "1"
D47…D69: Indexes of the LSF submatrices (s1…s23)
D70…D92: Indexes of the parameters of first sub-frame (s24…s46)
D93…D95: CRC1 over bits C1…C25, s1…s16, s19…s29, s42…s46.
D96…D114: Indexes of the parameters of second sub-frame (s47…s65)
D115…D117: CRC2 over bits s47…s48, s61…s65.
D118…D136: Indexes of the parameters of third sub-frame (s66…s84)
D137…D139: CRC3 over bits s66…s67, s80…s84.
D140…D158: Indexes of the parameters of fourth sub-frame (s85…s103)
D159…D161: CRC4 over bits s85…s86, s99…s103.
D162…D202: spare (41 bits); set to "1".

AMR_Mode 4,75 kBit/s, see GSM 06.90:
D32…D44: spare (13 bits); set to "1"
D45…D67: Indexes of the LSF submatrices (s1…s23)
D68…D92: Indexes of the parameters of first sub-frame (s24…s48)
D93…D95: CRC1 over bits C1…C25, s1…s16, s18, s19, s21…s29, s45…s48.
D96…D108: Indexes of the parameters of second sub-frame (s49…s61)
D109…D111: CRC2 over bits s49,s50.
D112…D132: Indexes of the parameters of third sub-frame (s62…s82)
D133…D135: CRC3 over bits s62, s63, s79…s82.
D136…D148: Indexes of the parameters of fourth sub-frame (s83…s95)
D149…D151: CRC4 over bits s83, s84.
D152…D202: spare (51 bits); set to "1".

Coding of No_Speech Frames:
The following tables define the contents of the Data bits when the Frame_Classification is set to "No_Speech". The three parity bits (CRC1) added are generated using the same cyclic code as defined for the Enhanced Full Rate (see clause 3.5.1.1.2). The TRAU Frame Formats in uplink and downlink direction are identical.

SID_Update and SID_Bad Frame:
D32…D34: No_Speech_Classification D35…D37: Codec_Mode_Indication_abs
D38…D40: Codec_Mode_Request_abs
D41: PAB: Phase Alignment Bit (optional)
D42…D43: TAE: Time Alignment Extension (optional)
D44…D57: reserved for TFO
D58…D60: Moving average predictor, initial values (s1…s3)
D61…D86: Indexes of LSF submatrices (s4…s29)
D87…D92: Logarithmic frame energy (s30…s35)
D93…D95: CRC1 over bits C1…C25, D32…D92.
D96…D207: spare (112 bits); set to "1".

No_Data, SID_First and Onset Frame:
Bits D32…D34: No_Speech_Classification Bits D35…D37: Codec_Mode_Indication_abs
Bits D38…D40: Codec_Mode_Request_abs
Bit D41: PAB: Phase Alignment Bit (optional)

Bits D42…D43: TAE: Time Alignment Extension (optional)
Bits D44…D57: reserved for TFO
Bits D58…D92: spare (35 bits); set to "1" Bits D93…D95: CRC1 over bits C1…C25, D32…D92.
Bits D96…D207: spare (112 bits); set to "1".

No_Speech_Classification:
If the Frame_Classification is set to "0.0", then the TRAU frame contains no speech parameters. The No_Speech_Classification is coded in the D-Bits:
D32…D34:
1.1.1: Sid_First
1.1.0: Onset
1.0.1: Sid_Update
1.0.0: Sid_Bad (SID_Update with bad parameters)
0.1.1: spare
0.1.0: spare
0.0.1: spare
0.0.0: No_Data (nothing received or frame has been stolen, e.g. by FACCH or RATSCCH).

Codec_Mode_Indication_abs (CMI_abs):
The meaning in uplink and downlink is identical. In No_Speech frames the CMI is always transmitted, independent of the setting of the RIF bit. Coding:
D35 . D36 . D37:
0.0.0 Codec_Mode 4,75 kBit/s
0.0.1 Codec_Mode 5,15 kBit/s
0.1.0 Codec_Mode 5,90 kBit/s
0.1.1 Codec_Mode 6,70 kBit/s
1.0.0 Codec_Mode 7,40 kBit/s
1.0.1 Codec_Mode 7,95 kBit/s
1.1.0 Codec_Mode 10,2 kBit/s
1.1.1 Codec_Mode 12,2 kBit/s

Codec_Mode_Request_abs (CMR_abs):
The meaning in uplink and downlink is identical. In No_Speech frames the CMR is always transmitted, independent of the setting of the RIF bit. Coding:
D38 . D39 . D40:
0.0.0 Codec_Mode 4,75 kBit/s
0.0.1 Codec_Mode 5,15 kBit/s
0.1.0 Codec_Mode 5,90 kBit/s
0.1.1 Codec_Mode 6,70 kBit/s
1.0.0 Codec_Mode 7,40 kBit/s
1.0.1 Codec_Mode 7,95 kBit/s
1.1.0 Codec_Mode 10,2 kBit/s
1.1.1 Codec_Mode 12,2 kBit/s

Phase Alignment Bit (PAB):
This bit is defined only in No_Speech frames. It is optional and shall be set to "0", if not used.
The PAB has exactly the same meaning and function as the Phase Alignment Command (PAC). For the exact procedure see clause 4.6.1.2.1.
PAB set to 0: CMI/CMR phase in downlink TRAU frames shall not be changed
PAB set to 1: CMI/CMR phase in downlink TRAU frames shall be inverted.
PAB shall only be used together with TAC values between 0.0.0.0.0.0 ("No change in frame timing") and 1.0.0.1.1.1 ("Delay frame 39 x 500ms").

Time Alignment Extension (TAE):
The TAE specifies optionally a Time Alignment Extension. Coding:
D42 . D43: Meaning:
0.0: No additional delay with respect to the Time Alignment Command
0.1 Additional delay of 125 µs
1.0 Additional delay of 250 µs
1.1 Additional delay of 375 µs
TAE together with the Time Alignment Command (TAC) allow a "one step" time alignment of 125 µs accuracy in No_Speech frames. TAE shall only be used together with TAC values between 0.0.0.0.0.0 ("No change in frame timing") and 1.0.0.1.1.1 ("Delay frame 39 x 500ms").
The TAC_TAE combination 0.0.0.0.0.0_0.1 shall be interpreted as "Delay frame by 125ms".
The TAC_TAE combination 1.0.0.1.1.1_1.0 shall be interpreted as "Advance frame by 250ms".
The TAC_TAE combination 1.0.0.1.1.1_1.1 shall be interpreted as "Advance frame by 125ms".

3.5.1.2.3 Time Alignment Bits (T1…T4)

The coding and meaning is as described in 3.5.1.1.3 (Time Alignment Bits).

3.5.2 Coding of O&M Frames

Control bits (C-bits):

Description

Uplink

Downlink

C1C2C3C4 C5

C1C2C3C4 C5

Frame type

0  0  1  0  1 : O&M

1  1  0  1  1 : O&M

Bits C1 – C5

Bits C6 – C15

Spare

Spare

Data Bits (D-bits):

Bits D1 .. D264: Bits used for transfer of O&M information. The coding and use of these bits are left to the manufacturer of the BSC/TRAU.

Spare Bits:

Bits S1 .. S6: Spare

3.5.3 Coding of Data Frames

Control bits (C-bits):

Description

Uplink

Downlink

Frame type.

C1C2C3C4 C5

C1C2C3C4 C5

Bits C1 – C5

 0  1  0  0  0  : Data

 1  0  1  1  0  : Data

except 14.5

except 14.5

 1  0  1  0  0 : Data14.5 (note)

 1  0  1  0  0  : Data 14.5 (note)

Intermediate RA bit

 0: 8 kbit/s

 0: 8 kbit/s

rate.

 1: 16 kbit/s

 1: 16 kbit/s

Bit C6

for data services

except 14.5

Spare

Spare

Spare

for Data 14.5

Bits C7 – C15

Spare

Spare

NOTE: The Data frame is in case of data 14.5 kbit/s used only for synchronization purposes. The data bits are in this case set according to clause 4.5.1.

3.5.4 Coding of Extended Data Frames

Control bits (C-bits):

Description

Uplink

Downlink

Frame type.

C1C2C3C4 C5

C1C2C3C4 C5

Bits C1 – C5

1  1  1  1  1 :

1  1  1  1  1 :

Extended Data

Extended data

frame 14.5 kbit/s

Frame 14.5

Bit C6

Idle/Data/UFE

Idle/data

UFE

Frame indication

Bits C7 – C13

Spare

Bit C7 indicating idle/data frame. Bit C8-C13 spare

Multi Frame Structure

M1, M2

M1, M2

defined in GSM 04.21

Bits M1, M2

3.5.5 Coding of Idle Speech Frames

Control bits (C-bits):

Description

Uplink

Downlink

C1C2C3C4 C5

C1C2C3C4 C5

Frame type.

1  0  0  0  0 : Idle Speech

0   1  1  1  0 : Idle Speech

Bits C1 – C5

Bits C6 – C21

Coding as for

Coding as for

Speech frames.

Speech frames.

NOTE: Idle Speech frames shall not be used in AMR; instead Frame_Classification set to "No_Data" shall be applied.

Time Alignment Bits:

Bits T1 .. T4: Coding as for Speech frames.

3.6 Order of Bit Transmission

The order of bit transmission is:

The first octet is transferred first with the bit no. 1 first, bit no. 2 next etc.