Speech communication in cars goes
wideband
–
the new ITU-T Focus Group CarCom
H.W. Gierlich
HEAD acoustics GmbH
Chair of ITU-T FG CarCom
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Outline
•
•
•
•
•
The stakeholders
The goals
The challenges
Schedule and future work
Conclusions
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The stakeholders
Parent study group
ITU-T SG12
Car
Industry
FG-Group
CarCom
Telecommunication
industry
Suppliers
to the
car industry
Algorithm
developers
Universities
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Why we do the work?
• Wideband services in mobile networks available soon
->
• Enabling wideband telephony (100 Hz- 8 kHz) in cars
• Fullband
• Narrow band
• Wideband
• Efficient use of the high quality audio systems in
cars:
•
•
•
•
Getting superior sound quality
Increasing speech intelligibility
Increasing naturalness of a conversation
Reduce drivers distraction due to poor speech quality
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The Goal
• Development of a standard for testing and
optimization
• the communication quality
• from cars to the mobile/fixed network
• from the car infrastructure to the mobile devices
• of audio components installed in a car and used
for hands-free communication
• wireless devices e.g. headsets used in a car
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The Configuration
Car
Preamp.
A/D
GSM
BT
MOSTHands-Free Algorithm
BUS
BT
chip
Mobile
Phone
GSM
Network
D/A
Amp.
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< 1ms
The Challenges - Delay
10 – 50 ms
~30 ms? 90 – 120 ms
Car
Preamp.
A/D
GSM
BT
MOSTHands-Free Algorithm
BUS
BT
chip
Mobile
Phone
GSM
Network
D/A
Amp.
1-20ms?
10 – 50 ms
~30 ms? 90 – 120 ms
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Delay
• Best case car to car:
~200 ms (no Bluetooth delay)
• Worst case car to car (no additional network
delay):
For superior conversational quality: delay < ~150 ms
~400 ms (from
(incl. Bluetooth
delay 30 ms)
the users perspective)
Terminal A
Network
0 ms
150 ms
500 ms
Terminal B
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The Challenges – Superior Noise
Cancellation
Narrowband
Wideband
Car
Preamp.
A/D
GSM
BT
MOSTHands-Free Algorithm
BUS
BT
chip
Mobile
Phone
GSM
Network
D/A
Amp.
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The Challenges – Superior Echo Cancellation
Car
Narrowband
Wideband
Preamp.
A/D
MOST-
Echo
GSM
BT
Hands-Free Algorithm
BUS
BT
chip
Mobile
Phone
GSM
Network
D/A
Amp.
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Main Focus of the CarCom Spec
• For a good conversational performance
we need to ensure:
Superior sound quality in all conversational
situations
¾ define requirements optimum frequency
responses and
¾ optimum loudness
¾ requirements for good performance in
background noise
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Main Focus of the CarCom Spec
• We need to ensure:
• Low delay including all components of the
connection
¾ limiting the delay usage in each component
¾ get in touch with other standards bodies to
¾ enable tandem free operation
¾ develop and implement protocols for providing
signalling information of signal processing in the
components involved in a connection
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Main Focus of the CarCom Spec
• We need to ensure:
• Excellent echo performance
¾ define requirements for required echo loss in
wideband:
¾ ensure superior echo loss in all conversational
situations, esp. double talk
¾ ensure sufficient echo loss with high delay
¾ avoid any impairment in double talk situations
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Schedule and Future Work:
The Focus Group CarCom
• Input from FITCAR
Specification for
• Mandate form ITU-T SG12
Narrowband
after finalizing narrowband
Hands-Free
specification as ITU-T
Recommendation P.1100
:
• “Kick off” new group FG
• Draft specification
CarCom – meeting June 08
available
:
:
:
• October 2009
• New Specification,
Wideband
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FG CarCom -> ITU-T SG12
Transfer of the FG CarCom specification
to ITU-T SG12:
¾Specification as an input document to the next
ITU-T SG 12 meeting
¾Adaptation of the specification to ITU-T rules
and requirements
¾Discussion of this draft in ITU-T SG12
¾Based on the result of the discussions: new
Draft Recommendation for approval by
members of ITU
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New Topics in FG CarCom
• Definition of car hands-free quality on a
sub-system level
• In-car communication
• Speech recognition – requirements on
preprocessing
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Conclusion
• Wideband speech services in the car would be a great
improvement for the user
• The requirements for a superior service are much
stronger than for narrowband
• Not all effects are yet fully understood
• The focus group CarCom specification is the first
comprehensive standard covering all conversational
aspects of wideband handset and speakerphone
conversation in cars
http://www.itu.int/md/T09http://www.itu.int/md/T09-FG.CARCOMFG.CARCOM-090306/sum/en
• Next meeting: Jan. 21.21.-22. 2010 in Vancouver
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