3 Definitions and abbreviations
26.4543GPPCodec for Enhanced Voice Services (EVS)Interface to Iu, Uu, Nb and MbRelease 17TS
3.1 Definitions
For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in 3GPP TR 21.905 [1].
Active EVS-CMR: EVS-CMR containing the requested (maximum) bit rate, (maximum) audio bandwidth and the major operation mode.
DL EVS-CMR: the most recent successfully in downlink (DL) received codec mode request, relevant for encoding at the local UE.
EVS Configuration for Iu: The MSC selects the EVS configuration for Iu and informs the MGW and the RNC in RAB Assignment.
EVS Configuration for Uu: The RNC selects the EVS configuration for Uu.
EVS Configuration for UE: The UE deducts the EVS configuration for UE from the Radio Bearer Configuration, i.e. the Set of TFCs.
EVS Configuration for Nb: The MSC selects the EVS configuration for Nb and informs the MGW.
major operation mode: This is either an EVS Primary mode of operation or an EVS AMR-WB IO mode of operation.
Set of available rates: Rates of the EVS Configuration for UE, constrained further by RNC allowed TFCs and further constrained by the UE autonomous rate.
UE autonomous rate: Maximum bit rate set by UE transport layer to optimize uplink performance (frame loss rate) if the TX power limit is reached.
UL EVS-CMR: EVS-CMR sent by the UE in uplink (UL); relevant for encoding at the remote media-sender (e.g. remote UE or remote CN Transcoder), requesting the (maximum) codec mode to be used on the local DL to the UE.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in 3GPP TR 21.905 [1].
BICC Bearer Independent Call Control
CN Core Network
CMR Codec Mode Request (for AMR and AMR-WB, often also used for EVS)
DL Downlink
EVS Enhanced Voice Services
EVS-CMR Codec Mode Request for EVS (here explicitly used to differentiate)
EVS-SID SID for EVS (here explicitly used to differentiate)
FQC Frame Quality Classification (Iu and Nb Interfaces)
IM-MGW IP Multimedia Media Gateway Function
Nb Interconnection point between two MGWs of the CS Core Network
Nc Interconnection point between two MSCs of the CS Core Network
NO_REQ No Requirement (is present)
Mb Interconnection point between the MGW of the CS Core Network and the IMS
NboIP Nb-Interface user plane transport over RTP/UDP/IP when SIP-I is used on Nc
RC Ack Rate Control Procedure Acknowledgement (on Iu)
RC Proc Rate Control Procedure Request (on Iu)
RFC RAB sub-flow Combination (on Iu and Nb)
RFCI RFC Indicator
RFCS RFC Set
SCR Source Controlled Rate, synonym for DTX
SIP-I SIP with encapsulated ISUP (variant of ISUP)
SMpSDU Support Mode for Predefined SDU sizes
TC Transcoder
TrFO Transcoder Free Operation
UMTS_EVS Name of the EVS Codec Type in CS Networks
Uu The radio interface between UTRAN and the User Equipment
WB-CMR CMR for AMR-WB
WB-SID SID for AMR-WB (and EVS AMR-WB IO)