A.3 Definitions, symbols and abbreviations

26.1933GPPAdaptive Multi-Rate - Wideband (AMR-WB) speech codecRelease 17Source controlled rate operationSpeech codec speech processing functionsTS

A.3.1 Definitions

For the purpose of the present document, the following definitions apply.

frame: Time interval of 20 ms, corresponding to the time segmentation of the Adaptive Multi-Rate Wideband speech transcoder (3GPP TS 26.190 [9]), also used as a short term for a traffic frame.

traffic frame: Block of 132..397 information bits transmitted on the TCH/WFS or TCH/WHS speech traffic channels.

SID frame: Frame characterised by the SID (Silence Descriptor) gross bit patterns. It may convey information on the acoustic background noise.

speech frame: Traffic frame that has been classified as a SPEECH_GOOD, SPEECH_BAD or SPEECH_LOST frame.

VAD flag: Boolean flag, generated by the VAD algorithm defined in 3GPP TS 26.194 indicating the presence ("1") or the absence ("0") of a speech frame.

RX_TYPE: flag with eight values, generated by the RX radio subsystem, indicating to the RX DTX handler the type of data in the current frame. Refer to Table 2.

TX_TYPE: flag with eight values, generated by the TX DTX handler, indicating to the TX radio subsystem the type of data in the current frame. Refer to Table 1.

hangover period: A period of 7 frames added at the end of a speech burst in which VAD flag ="0" and TX_TYPE is "SPEECH".

A.3.2 Symbols

For the purpose of the present document, the following symbols apply.

Nelapsed Number of elapsed frames since the last updated SID frame.

A.3.3 Abbreviations

For the purpose of the present document, the following abbreviations apply.

BSC Base Station Controller

BSS Base Station System

BTS Base Transceiver Station

CHD Channel Decoder

CHE Channel Encoder

DTX Discontinuous Transmission

ETS European Telecommunication Standard

FACCH Fast Associated Control CHannel

GSM Global System for Mobile Telecommunications

MS Mobile Station

RATSCCH Robust Amr Traffic Synchronised Control CHannel

RSS Radio Sub System

RX Receive

SACCH Slow Associated Control CHannel

SID SIlence Descriptor

TX Transmit

VAD Voice Activity Detector

For abbreviations not given in this subclause, see 3GPP TS 21.004.