Content for TS 26.102 Word version: 18.0.0

...

1 Scope p. 6

The present document specifies the mapping of the AMR generic frame format (TS 26.101) to the Iu Interface (TS 25.415), the Uu Interface and the Nb Interface (TS 29.415). It further specifies the mapping of Enhanced Full Rate (GSM_EFR) coded speech and of PCM 64 kBit/s (ITU-T G.711 [9]) coded speech to the Nb Interface in a BICC-based circuit switched core network.

The present document also specifies the mapping of Full Rate (GSM_FR) coded speech and of Half Rate (GSM_HR) coded speech to the Nb Interface in a BICC-based circuit switched core network.

The present document also specifies the transport of the AMR Codec Types, the AMR-WB Codec Types, the GSM_EFR Codec, the GSM_FR Codec, the GSM_HR Codec and the ITU-T G.711 Codec over the A-Interface over IP (TS 48.002) and the Nb-Interface in a SIP-I -based circuit switched core network (TS 23.231).

2 References p. 6

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]

TS 25.415: "Iu Interface CN-UTRAN User plane Protocols".

[2]

TS 26.101: "AMR Speech Codec, Frame structure".

[3]

TS 23.107: "QoS Concept and Architecture".

[4]

TS 46.051: "Enhanced Full Rate (EFR) speech processing functions; General Description"

[5]

TS 28.062: "Inband Tandem Free Operation (TFO) of speech codecs; Service description; Stage 3".

[6]

TS 23.153: "Out of band transcoder control, Stage 2".

[7]

TS 29.415: "Core Network Nb Interface User Plane Protocols".

[8]

ITU-T I.366.2: "AAL type 2 service specific convergence sublayer for trunking".

[9]

ITU-T Recommendation G.711: "Pulse code modulation (PCM) of voice frequencies".

[10]

TS 29.414: "Core Network Nb data transport and transport signalling".

[11]

TS 48.002: "Base Station System - Mobile-services Switching Centre (BSS - MSC) interface; Interface principles".

[12]

TS 23.231: "SIP-I based circuit-switched core network; Stage 2".

[13]

TS 29.007: "General requirements on interworking between the Public Land Mobile Network (PLMN) and the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)".

[14]

TS 26.103: "Speech codec list for GSM and UMTS ".

[15]

RFC 3264 (2002): "An Offer/Answer Model with the Session Description Protocol (SDP)", J. Rosenberg and H. Schulzrinne.

[16]

RFC 3550 (2003): "RTP: A Transport Protocol for Real-Time Applications", H. Schulzrinne, S. Casner, R. Frederick and V. Jacobson.

[17]

RFC 3551 (2003): "RTP Profile for Audio and Video Conferences with Minimal Control", H. Schulzrinne and S. Casner.

[18] Void

[19]

RFC 4566 (2006): "SDP: Session Description Protocol", M. Handley, V. Jacobson and C. Perkins.

[20]

RFC 4733 (2006): "RTP Payload for DTMF Digits, Telephony Tones, and Telephony Signals", H. Schulzrinne and T. Taylor.

[21]

RFC 4867 (2007): "RTP Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs", J. Sjoberg, M. Westerlund, A. Lakaniemi and Q. Xie.

[22]

RFC 5993 (2010) "RTP Payload Format for Global System for Mobile Communications Half Rate (GSM-HR)".

[23]

TS 46.010: "Full rate speech; Transcoding".

[24]

TS 46.020: "Half rate speech; Half rate speech transcoding".

[25]

TS 46.041: "Half rate speech; Discontinuous Transmission (DTX) for half rate speech traffic channels".

[26]

TS 48.060: "In-band control of remote transcoders and rate adaptors for full rate traffic channels".

[27]

TS 48.061: "In band control of remote transcoders and rate adaptors for half rate traffic channels".

[28]

TS 46.012: "Full rate speech; Comfort noise aspect for full rate speech traffic channels".

[29]

TS 46.022: "Half rate speech; Comfort noise aspects for half rate speech traffic channels".

[30]

TS 46.062: "Comfort noise aspects for Enhanced Full Rate (EFR) speech traffic channels".

[31]

TS 26.093: "Adaptive Multi-Rate (AMR) speech codec; Source controlled rate operation".

[32]

TS 26.193: "Adaptive Multi-Rate - Wideband (AMR-WB) speech codec; Source controlled rate operation".

[33]

TS 48.008: "Mobile Switching Centre - Base Station System (MSC-BSS) interface".

[34]

TS 48.103: "Base Station System - Media GateWay (BSS-MGW) interface; User Plane transport mechanism".

[35]

TS 45.009: "Radio Access Network; Link adaptation"

[36]

TS 46.060: "EFR Speech Codec; Speech Transcoding Functions"

3 Definitions and abbreviations p. 7

3.1 Definitions p. 7

For the purposes of the present document the following terms and definitions apply:

AMR Generic Frame Interface:

this interface transports the AMR IF1 generic frame as defined in TS 26.101

3.2 Abbreviations p. 8

For the purposes of the present document, the following abbreviations apply:

AAL2

ATM Adaptation Layer 2

ACS

Active Codec Set

AMR

Adaptive Multi-Rate

AoIP

A-Interface user plane transport over RTP/UDP/IP

Access Stratum

ATM

Asynchronous Transfer Mode

BFH

Bad Frame Handling

CDMA

Code Division Multiple Access

CMI

Codec Mode Indication

CMR/CMC

Codec Mode Request or Codec Mode Command

Core Network

DRC

Downlink Rate Command

FDD

Frequency Duplex Division

FQC

Frame Quality Classification (Iu Interface)

FQI

Frame Quality Indication (AMR IF1)

GSM

Global System for Mobile communications

ITU-T

International Telecommunication Union - Telecommunication standardisation sector

MGW

Media GateWay

NboIP

Nb-Interface user plane transport over RTP/UDP/IP when SIP-I is used on Nc

PCM

Pulse Code Modulation, synonym for 64 kBit/s coded speech (see ITU-T G.711 [9])

PDC

Personal Digital Communication

PLMN

Public Land Mobile Network

QoS

Quality of Service

RAB

Radio Access Bearer

RAN

Radio Access Network

Radio Frequency

RFC

RAB sub-flow Combination

RFCI

RFC Indicator

RFCS

RFC Set

Receive

SCR

Source Controlled Rate

SDU

Source Data Unit

SID

Silence Insertion Descriptor

SMpSDU

Support Mode for Predefined SDU sizes

SPD

SPeech Decoder

SPE

SPeech Encoder

Transcoder

TDD

Time Duplex Division

TDMA

Time Division Multiple Access

TFO

Tandem Free Operation

TrFO

Transcoder Free Operation

Transmit

User Equipment (terminal)

URC

Uplink Rate Command

4 General p. 8

The Iu-Interface is defined in two different variants for speech telephony,

for the ATM bearer with Iu-framing and
for the IP bearer with Iu-framing.

The Nb-Interface is defined in three different variants for speech telephony,

for the ATM bearer with Nb-framing in a BICC-based Core Network,
for the IP bearer with Nb-framing in a BICC-based Core Network and
for the IP bearer with RTP packetization in a SIP-I -based Core Network, also called NboIP.

The mapping of the AMR Speech Codec parameters to the Iu interface specifies the frame structure of the speech data exchanged between the RNC and the TC inside the MGW in case of normal operation. This mapping is independent from the radio interface in the sense that it has the same structure for both FDD and TDD modes of the UTRAN.

The mapping between the Speech Codec and the Radio Access Network within the UE is not an open interface and need not to be detailed.

The mapping on the Nb Interface in a BICC based Core Network is identical to the one on the Iu Interface in case of Transcoder Free Operation, with the MGW relaying the SDUs unaltered between Iu and Nb Interfaces.

PCM coded speech is mapped onto the Nb-Interface in packets of 40 octets (5ms packetization time) or 160 octets (20ms packetization time). With Nb-framing (i.e. in a BICC-based Circuit Switched Core Network, IP or ATM) the default packetization time for PCM-coded speech is 5ms; 20ms is an additional option. For NboIP (i.e. RTP packetization in a SIP-I -based Circuit Switched Core Network) the default packetization time for PCM-coded speech is 20ms; 5ms is an additional option.

The packetization time of PCM-coded speech for AoIP is 20ms without any other option.

For the 3GPP Codec Types (GSM_FR, GSM_HR, GSM_EFR, AMR and AMR-WB) the framing is always 20ms and also the packetization time is 20ms in all versions of the Nb-Interface and the A-Interface over IP. The mapping of GSM_FR, GSM_HR and GSM_EFR Speech Codec parameters is defined on the A Interface over IP and all versions of the Nb-Interface, but not on the Iu Interface.