ETSI TS 148 061 V13.0.0 (2016-01)

ETSI TS 1148 061 V13.0.0 (201616-01)






TECHNICAL SPECIFICATIONION
Digital cellular telecocommunications system (Phahase 2+);
In-band control of remremote transcoders and rate a adaptors
for halalf rate traffic channels
(3GPP TS 48.0.061 version 13.0.0 Release 13 13)

R
GLOBAL SYSTTEME FOR
MOBILE COMMUUNNICATIONS

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3GPP TS 48.061 version 13.0.0 Release 13 1 ETSI TS 148 061 V13.0.0 (2016-01)



Reference
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ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 2 ETSI TS 148 061 V13.0.0 (2016-01)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (https://ipr.etsi.org/).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Specification (TS) has been produced by ETSI 3rd Generation Partnership Project (3GPP).
The present document may refer to technical specifications or reports using their 3GPP identities, UMTS identities or
GSM identities. These should be interpreted as being references to the corresponding ETSI deliverables.
The cross reference between GSM, UMTS, 3GPP and ETSI identities can be found under
http://webapp.etsi.org/key/queryform.asp.
Modal verbs terminology
In the present document "shall", "shall not", "should", "should not", "may", "need not", "will", "will not", "can" and
"cannot" are to be interpreted as described in clause 3.2 of the ETSI Drafting Rules (Verbal forms for the expression of
provisions).
"must" and "must not" are NOT allowed in ETSI deliverables except when used in direct citation.
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 3 ETSI TS 148 061 V13.0.0 (2016-01)
Contents
Intellectual Property Rights . 2
Foreword . 2
Modal verbs terminology . 2
Foreword . 5
1 Scope . 6
2 References . 6
3 Definitions and abbreviations . 7
3.1 Definitions . 7
3.2 Abbreviations . 7
4 General approach . 8
5 Frame structure . 10
5.1 16 kbit/s submultiplexing . 10
5.1.1 Frames for Speech Services . 10
5.1.1.1 Frame for Half Rate speech . 10
5.1.1.2 Frames for Adaptive Multi-Rate Speech . 10
5.1.2 Data frame . 11
5.1.3 O&M frame . 12
5.1.4 Coding . 12
5.1.4.1 Coding of frames for speech services. 13
5.1.4.1.1 Coding of frames for Half Rate speech Control bits (C-bits): . 13
5.1.4.1.2 Coding of frames for Adaptive Multi-Rate speech . 14
5.1.4.2 Coding of data frames . 14
5.1.4.3 Coding of O&M frames . 15
5.1.5 Order of Bit Transmission . 15
5.2 8 kbit/s submultiplexing . 16
5.2.1 Frames for Speech Services . 16
5.2.1.1 Frame for Half Rate Speech . 16
5.2.1.2 Frames for Adaptive Multi-Rate Speech . 16
5.2.1.2.1 Frame for Lower Codec Modes . 16
5.2.1.2.2 Speech frame for Codec Mode 6,70 kBit/s . 17
5.2.1.2.3 Speech frame for Codec Mode 7,40 kBit/s . 17
5.2.1.2.4 Speech frame for Codec Mode 7,95 kBit/s . 18
5.2.1.3 Frames for Speech Codec Configuration Exchange . 18
5.2.2 Data frame . 19
5.2.3 O&M frame . 19
5.2.4 Coding . 20
5.2.4.1 Coding for Half Rate Speech and Half Rate Data Services . 20
5.2.4.1.1 Uplink coding . 20
5.2.4.1.2 Downlink coding . 22
5.2.4.2 Coding for Adaptive Multi-Rate Speech . 23
5.2.4.2.1 No_Speech Frame . 23
5.2.4.2.2 Speech Frames for 4,75, 5,15 and 5,90 kBit/s . 24
5.2.4.2.3 Speech Frame for 6,70 kBit/s . 25
5.2.4.2.4 Speech Frame for 7,40 kBit/s . 26
5.2.4.2.5 Speech Frame for 7,95 kBit/s . 26
5.2.5 Order of Bit Transmission . 26
6 Procedures . 27
6.1 Remote Control of Transcoders and Rate Adaptors . 27
6.2 Resource Allocation . 27
6.3 Resource Release . 27
6.4 In Call Modification . 28
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 4 ETSI TS 148 061 V13.0.0 (2016-01)
6.5 Transfer of Idle Frames, Handling of missing data . 28
6.6 Procedures for Speech Frames . 28
6.6.1 Time Alignment of Speech Frames . 28
6.6.1.1 16 kbit/s submultiplexing . 29
6.6.1.1.1 Downlink Time Alignment . 29
6.6.1.1.2 Uplink Time Alignment . 31
6.6.1.1.3 Initiation at Resource Allocation . 31
6.6.1.1.4 Time Alignment during Handover. 31
6.6.1.2 8 kbit/s submultiplexing . 31
6.6.1.2.1 Downlink Time Alignment . 31
6.6.1.2.2 Uplink Time Alignment . 33
6.6.1.2.3 Initiation at Resource allocation . 34
6.6.1.2.4 Time Alignment during handover . 34
6.6.2 Procedures for Discontinuous Transmission (DTX) . 34
6.6.2.1 DTX procedures in the uplink direction . 34
6.6.2.2 DTX procedures in the downlink direction . 35
6.7 Procedures for Data Frames . 35
6.7.1 The RAA Function . 35
6.7.2 The RA1/RA1' Function . 36
6.7.3 The RA2 Function . 36
6.7.4 Procedures for 8 kbit/s intermediate rate adaption rate . 36
6.7.5 Support of Non-Transparent Bearer Applications . 37
6.8 Frame Synchronization . 37
6.8.1 16 kbit/s submultiplexing . 37
6.8.1.1 Search for Frame Synchronization . 37
6.8.1.2 Frame Synchronization After Performing Downlink Timing Adjustments . 37
6.8.1.3 Frame Synchronization Monitoring and Recovery . 37
6.8.2 8 kbit/s submultiplexing . 38
6.8.2.1 Search for Frame Synchronization . 38
6.8.2.1.1 For Half Rate speech and data . 38
6.8.2.1.2 For Adaptive Multi-Rate speech . 38
6.8.2.2 Frame Synchronization Monitoring and Recovery . 39
6.8.2.2.1 For Half Rate speech and data . 39
6.8.2.2.2 For Adaptive Multi-Rate speech . 39
6.9 Correction/detection of bit errors . 39
6.9.1 16 kbit/s submultiplexing . 39
6.9.1.1 Error Detection on the Control Bits . 39
6.9.1.1.1 General Procedure . 39
6.9.1.1.2 Frames for Half Rate speech . 40
6.9.1.2 Handling of frames received with errors for Half Rate speech and data . 40
6.9.2 8 kbit/s submultiplexing . 40
6.9.2.1 Error Detection on the Control Bits . 40
6.9.2.2 Handling of frames received with errors . 41
6.10 Procedures for Operation & Maintenance . 41
6.10.1 Transfer of O&M Information Between the TRAU and the BSC . 41
6.10.2 Procedures in the TRAU . 41
6.10.3 Procedures in the BSC . 41
6.10.3.1 Use of O&M Frames . 41
6.10.4 Procedures in the BTS . 42
Annex A (informative): Change History . 43
History . 44


ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 5 ETSI TS 148 061 V13.0.0 (2016-01)
Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.

ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 6 ETSI TS 148 061 V13.0.0 (2016-01)
1 Scope
The present document describes the protocol between the Base Transceiver Station (BTS) and the remote
Transcoder/Rate Adaption Unit (TRAU) for speech and data on half rate traffic channel (TCH/H).
For Half Rate speech and half rate data the protocol is specified for 8 kbit/s and 16 kbit/s submultiplexing scheme.
For Adaptive Multi-Rate speech the present document specifies the 8 kBit/s submultiplexing, both for the full and the
half rate traffic channels (TCH/AFS and TCH/AHS). The specification for 16 kBit/s submultiplexing is given in Rec
3GPP TS 48.060, both for the full and the half rate traffic channels (TCH/AFS and TCH/AHS).
The present document should be considered together with the 3GPP TS 46 series, 3GPP TS 44.021 (Rate Adaption on
the MS-BSS Interface) and 3GPP TS 48.020 (Rate Adaption on the BTS/MSC Interface).
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TS 01.02: "Digital cellular telecommunication system (Phase 2+); General description of a
GSM Public Land Mobile Network (PLMN)".
[2] 3GPP TS 21.905: "Vocabulary for 3GPP Specifications".
[3] 3GPP TS 44.021: "Rate adaption on the Mobile Station - Base Station System (MS - BSS)
interface".
[4] 3GPP TS 45.003: "Channel coding".
[5] 3GPP TS 46.021: "Half rate speech; Substitution and muting of lost frames for half rate speech
traffic channels".
[6] 3GPP TS 46.022: "Half rate speech; Comfort noise aspects for half rate speech traffic channels".
[7] 3GPP TS 46.041: "Half rate speech; Discontinuous Transmission (DTX) for half rate speech
traffic channels".
[8] 3GPP TS 46.042: "Half rate speech; Voice Activity Detector (VAD) for half rate speech traffic
channels".
[9] 3GPP TS 48.008: "Mobile-services Switching Centre – Base Station System (MSC-BSS)
interface; Layer 3 specification".
[10] 3GPP TS 48.020: "Rate adaption on the Base Station System - Mobile-services Switching Centre
(BSS - MSC) interface".
[11] 3GPP TS 48.052: "Base Station Controller - Base Transceiver Station (BSC - BTS) interface;
Interface principles".
[12] 3GPP TS 48.054: "Base Station Controller - Base Transceiver Station (BSC - BTS) interface
Layer 1 structure of physical circuits".
[13] 3GPP TS 48.058: "Base Station Controller - Base Transceiver Station (BSC - BTS) interface;
Layer 3 specification".
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 7 ETSI TS 148 061 V13.0.0 (2016-01)
[14] 3GPP TS 12.21: "Digital cellular telecommunication system (Phase 2); Network Management
(NM) procedures and messages on the A-bis interface".
[15] ITU-T Recommendation I.460: "Multiplexing, rate adaption and support of existing interfaces".
[16] ITU-T Recommendation V.110: "Support of data terminal equipments (DTEs) with V-Series
interfaces by an integrated services digital network".
[24] 3GPP TS 26.071: "Adaptive Multi-Rate speech processing functions, General Description."
[25] 3GPP TS 26.090: "Adaptive Multi-Rate speech transcoding".
[26] Void.
[27] 3GPP TS 26.092: "Comfort noise aspect for Adaptive Multi-Rate speech traffic channels".
[28] Void.
[29] Void.
[30] Void.
[31] 3GPP TS 48.060: "Inband control of remote transcoders and rate adaptors".
[32] 3GPP TS 48.062: "Inband Tandem Free Operation (TFO) of Speech Codecs".
[33] 3GPP TS 46.020: "Half Rate Speech Transcoding".
3 Definitions and abbreviations
3.1 Definitions
No specific definitions apply to the present document.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
ACS Active_Codec_Set
AMR Adaptive Multi-Rate
BSC Base Station Controller
BTS Base Transceiver Station
CCU Channel Codec Unit
CMC Codec_Mode_Command
CMI Codec_Mode_Indication
CMR Codec_Mode_Request
DFE Downlink Frame Error
ICM Initial_Codec_Mode
PAB Phase Alignment Bit
PAC Phase Alignment Command
RA Rate Adaption
RIF Request or Indication Flag
TAC Time Alignment Command
TAE Time Alignment Extension
TFO Tandem Free Operation
TFOE TFO Enable
TRAU Transcoder and Rate Adaption Unit
UFE Uplink Frame Error
Other abbreviations used in the present document are listed in 3GPP TS 21.905.
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 8 ETSI TS 148 061 V13.0.0 (2016-01)
4 General approach
The TRAU shall be controlled by the BTS when it is positioned remote from the BTS. In this case, the speech/data
information and TRAU control signals exchanged between the Channel Codec Unit (CCU) in the BTS and the TRAU
shall be transferred in frames denoted "TRAU frames".
The TRAU frames may be carried by either 16 kbit/s traffic channels or 8 kbit/s channels. The choice of the traffic
channel bit rate or submultiplexing scheme is operator dependent.
The TRAU frames have a fixed length of:
- 160 bits (20 ms) when 8 kbit/s submultiplexing is used;
- 320 bits (20 ms) when 16 kbit/s submultiplexing is used.
The protocol between the BTS and the TRAU should be the same if the TRAU is positioned either at the MSC site or at
the BSC site. In the first case, the BSC should be considered as transparent for 16 kbit/s and 8 kbit/s channels.
The TRAU is considered a part of the BSC when the TRAU is remote from the BTS (see 3GPP TS 48.052), and the
signalling between the BSC and the TRAU (e.g. detection of call release, handover and transfer of O&M information)
may be performed by using BSC internal signals. However, the signalling between the CCU and the TRAU, using
TRAU frames as specified in the present document, is mandatory when the TRAU is remote from the BTS.
For data transfer, a conversion function is required, in addition to the conversion/rate adaption specified in 3GPP TS
48.020, to adapt ITU-T V.110 frames to the TRAU data frames. This function constitutes the RAA.
NOTE: If standard 64 kbit/s switching is used in the BSC, multiplexing according to ITU-T Recommendation
I.460 should apply at both sides of the switch.
A possible configuration of the TRAU and the CCU is shown in figure 4.1.
The functions inside the TRAU are:
- "Remote Transcoder and Rate Adaptor Control Function" (RTRACF);
- "Remote Speech Handler Function" (RSHF);
- the RAA function;
- the RA2 function;
- the transcoder function.
The functions inside the CCU are:
- "Transcoder and Rate Adaptor Control Function" (TRACF);
- "Speech Handler Function" (SHF);
- the RAA function;
- the RA1/RA1' function;
- the channel codec function.
The present document does not describe the procedures inside the TRAU and the CCU. The layout in figure 4.1 is only
intended as a reference model.
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 9 ETSI TS 148 061 V13.0.0 (2016-01)
Remote
Transcoder Speech
Speech
Function Handler
Handler
(note) Function
Function
Speech
Speech
8kbit/s
Remote 160bit/20ms
Transcoder
Transcoder
Channel
and RA
and RA
Codec
Control
Control
Function
Function
Function
Radio
64kbit/s
16 kbit/s
L3 control
frames
320bit/20ms signals
Data
RA2 RAA RAA RA1 RA1'
Data
Control
Speech/Data

NOTE: This technical specification assumes the DTX handler function to be part of the Transcoder Function.

Figure 3GPP TS 48.061/4.1: Functional entities for handling of control
of remote transcoders and rate adaptors
ETSI

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3GPP TS 48.061 version 13.0.0 Release 13 10 ETSI TS 148 061 V13.0.0 (2016-01)
5 Frame structure
5.1 16 kbit/s submultiplexing
5.1.1 Frames for Speech Services
5.1.1.1 Frame for Half Rate speech

Bit number
Octet no.
1 2 3 4 5 6 7 8
1 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
3 1 C1 C2 C3 C4 C5 C6 C7
4 C8 C9 C10 C11 C12 C13 C14 C15
5 1 UFI D1 D2 D3 D4 D5 D6
6 D7 D8 D9 D10 D11 D12 D13 D14
7 1 D15 D16 D17 D18 D19 D20 D21
8 D22 D23 D24 D25 D26 D27 D28 D29
9 1 D30 D31 D32 D33 D34 D35 D36
10 D37 D38 D39 D40 D41 D42 D43 D44
11 1 CRC2 CRC1 CRC0 D45 D46 D47
...