3 Definitions, symbols and abbreviations
06.933GPPDiscontinuous Transmission (DTX) for Adaptive Multi-Rate speech traffic channelsTS
3.1 Definitions
For the purpose of the present document, the following terms and definitions apply:
frame: time interval of 20 ms, corresponding to the time segmentation of the Adaptive Multi Rate speech transcoder (GSM 06.90 [9]), also used as a short term for a traffic frame
traffic frame: block of 95.244 information bits transmitted on the TCH/AFS or TCH/AHS 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 frame
VAD flag: boolean flag, generated by the VAD algorithm defined in GSM 06.94 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 (efer 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: period of 7 frames added at the end of a speech burst in which VAD flag ="0" and TX_TYPE is "SPEECH"
3.2 Symbols
For the purpose of the present document, the following symbol apply:
Nelapsed Number of elapsed frames since the last updated SID frame
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 clause, see GSM 01.04.