3 Definitions, symbols and abbreviations

26.1923GPPAdaptive Multi-Rate - Wideband (AMR-WB) speech codecComfort noise aspectsRelease 17Speech codec speech processing functionsTS

3.1 Definitions

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

Frame: Time interval of 20 ms corresponding to the time segmentation of the adaptive multi-rate wideband speech transcoder, also used as a short term for traffic frame.

SID frames: Special Comfort Noise frames. It may convey information on the acoustic background noise or inform the decoder that it should start generating background noise.

Speech frame: Traffic frame that cannot be classified as a SID frame.

VAD flag: Voice Activity Detection flag.

TX_TYPE: Classification of the transmitted traffic frame (defined in [4]).

RX_TYPE: Classification of the received traffic frame (defined in [4]).

Other definitions of terms used in this document can be found in [2] and [4]. The overall operation of SCR is described in [4].

3.2 Symbols

For the purpose of this document, the following symbols apply. Boldface symbols are used for vector variables.

Unquantized ISF vector

Quantized ISF vector

Unquantized ISF vector of frame m

Quantized ISF vector of frame m

Averaged ISF parameter vector

Logarithmic frame energy

Averaged logarithmic frame energy

ISF parameter prediction residual

Quantized ISF parameter prediction residual

3.3 Abbreviations

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

AMR Adaptive Multi-Rate

AMR-WB Adaptive Multi-Rate Wideband

CN Comfort Noise

SCR Source Controlled Rate operation ( aka source discontinuous transmission )

UE User Equipment

SID SIlence Descriptor

LP Linear Prediction

ISP Immittance Spectral Pair

ISF Immittance Spectral Frequency

RSS Radio Subsystem

RX Receive

TX Transmit

VAD Voice Activity Detector