TRAU
Encyclopedia
Transcoder and Rate Adaptation Unit, or TRAU, performs transcoding function for speech channels and RA (Rate Adaptation) for data channels in the GSM network.
Transcoding is the compression of speech data from 64 kbit/s to 13/12.2/5.6 kbit/s in case FR/EFR/HR (respectively) speech coding.
=> Gross data rate after adding redundancy = 22.8 kbit/s
=
12.2 kbit/s for EFR (Enhanced Full Rate), Redundancy (Channel Coding)= 10.6 kbit/s
=> Gross data rate after adding redundancy = 22.8 kbit/s (same as FR)
TRAU changes the bit rate of 16Kb/s of the BSS side to 64Kb/s of NSS side.
=
5.6 kbit/s for HR (Half Rate), Redundancy (Channel Coding)= 5.8 kbit/s
=> Gross data rate after adding redundancy = 11.4 kbit/s
TRAU was also the term used for the frame format used in transport of the compressed bits from these speech coders.
Transcoding is the compression of speech data from 64 kbit/s to 13/12.2/5.6 kbit/s in case FR/EFR/HR (respectively) speech coding.
Brief Explanation
13 kbit/s for FR (Full Rate), Redundancy (Channel Coding)= 9.8 kbit/s=> Gross data rate after adding redundancy = 22.8 kbit/s
=
12.2 kbit/s for EFR (Enhanced Full Rate), Redundancy (Channel Coding)= 10.6 kbit/s
=> Gross data rate after adding redundancy = 22.8 kbit/s (same as FR)
TRAU changes the bit rate of 16Kb/s of the BSS side to 64Kb/s of NSS side.
=
5.6 kbit/s for HR (Half Rate), Redundancy (Channel Coding)= 5.8 kbit/s
=> Gross data rate after adding redundancy = 11.4 kbit/s
See also
- Full RateFull RateFull Rate or FR or GSM-FR or GSM 06.10 was the first digital speech coding standard used in the GSM digital mobile phone system. The bit rate of the codec is 13 kbit/s, or 1.625 bits/audio sample...
- Half RateHalf RateHalf Rate is a speech coding system for GSM, developed in the early 1990s.Since the codec, operating at 5.6 kbit/s, requires half the bandwidth of the Full Rate codec, network capacity for voice traffic is doubled, at the expense of audio quality. It is recommended to use this codec when the...
- Enhanced Full RateEnhanced Full RateEnhanced Full Rate or EFR or GSM-EFR or GSM 06.60 is a speech coding standard that was developed in order to improve the quite poor quality of GSM-Full Rate codec. Working at 12.2 kbit/s the EFR provides wirelike quality in any noise free and background noise conditions...
- Adaptive Multi-RateAdaptive Multi-RateThe Adaptive Multi-Rate audio codec is a patented audio data compression scheme optimized for speech coding. AMR was adopted as the standard speech codec by 3GPP in October 1999 and is now widely used in GSM and UMTS...
TRAU was also the term used for the frame format used in transport of the compressed bits from these speech coders.