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Question 4/12

Question 4/12 – Hands-free communication and user interfaces in vehicles
(Continuation of Question 4/12)


Car infotainment systems, telematic services and all types of mobile communication services are used increasingly in vehicles; an increasing number of modern cars are equipped with integrated infotainment and communication systems. In order to provide a good user experience, low driver distraction and satisfying communication quality under all driving conditions, a variety of user interfaces and technologies have to seamlessly interact and optimized for the car environment. All services and technologies deployed in the car should not distract the driver from his main task, advanced hands-free devices are required which require sophisticated signal processing adapted to the individual car to provide superior speech quality for the driver as well as for far end conversational partner. Recommendations were developed describing the transmission requirements of for narrowband and wideband speakerphones (also based on the output of the FG. CarCOM).

The use of headsets or other hands-free devices, is becoming mandated in an increasing number of countries and states throughout the world. A large percentage of the target market for these vehicles will own headsets prior to purchasing a vehicle equipped with infotainment systems. They will expect to continue to use them in the vehicle, and thus will expect the vehicle to exploit the headset. The introduction of wireless headsets (e.g. Bluetooth, 802.11, DECT) requires the definition of standard behaviours and interactions with the vehicle.

The study within the Question is be based on the existing Recommendations P.340, P.313, P.501, P.502, P.583, P.1100, P.1110 and the ongoing work on P.ONRA. The main focus of the Question will be hands-free systems, subsystem requirements in cars, in car communication systems and requirements on the design of user interfaces in the car.
The following Recommendations, in force at the time of approval of this Question, fall under its responsibility:

 P.1100, P.1110


The following items are to be considered within the study of the Question:

  • How can the driving situation be simulated while covering the most relevant parameters influencing driver distraction and the speech quality within a laboratory environment?
  •  What requirements and design guidelines are needed for user interfaces in the car?
  • Which are the most influencing communicational speech quality parameters in the driving situation, especially in wideband communication and to what extent are they different from standard hands-free situations?
  • What are the most influential parameters for speech recognition systems in the driving situation?
  • Which of the newly developed methodologies known in ITU can be used and/or adapted to the car hands-free situation?
  • Do different mobile networks and network configurations require individual setups for specific parameters?
  • What is the current state of definition of the behaviour of a wireless or wired headset in the environment of a telematics enabled motor vehicle?
  • What are the desirable features to be presented by the vehicle, and what is their behaviour when operating with a hands-free device?
  • What enhancements of the new Recommendations P.1100 and P.1110 are needed to be developed to ensure seamless support for users of hands-free devices?
  •  Considerations on how to help measure and mitigate climate change.


The work to be performed should cover the following tasks:

  • Define the typical operating conditions to be simulated covering the most relevant parameters determining the user experience and influencing driver distraction.
  • Define the typical operating conditions to be simulated covering the most relevant parameters influencing the speech quality within a laboratory environment.
  •  Define the typical operating conditions to be simulated covering the most relevant parameters influencing the quality of in-car communication systems within a laboratory environment.
  • Define the typical operating conditions to be simulated covering the most relevant parameters influencing automated speech recognition performance within a laboratory environment.
  • Laboratory setup and general testing conditions in order to simulate the driving situation for subjective and objective testing ("Car-simulator").
  •  Definition of the environmental conditions for testing the car hands-free terminal and verifying its acoustical performance characteristics under typical operating conditions.
  • Definition of the environmental conditions for testing the car hands-free subsystems and verifying their performance characteristics under typical operating conditions including the definition of QoS classes for such subsystems.
  • Definition of the superwideband telephonometric parameters needed in order to describe/evaluate the communicational speech quality in typical operating conditions.
  • Specification of all relevant transmission characteristics
  • Definition test signals and testing techniques for superwideband systems in order to evaluate all relevant parameters of modern hands-free terminals which include highly non-linear and time variant signal processing such as background noise reduction, echo cancellation, AGC, compression.
  •  Definition of test procedures for evaluating automated speech recognition
  • Define the performance characteristics and test setup for headsets.
  • Define requirements for ICT systems that interact with drivers of vehicles.
  • Capture in Use Cases the proposed behaviour and interactions of a vehicle and hands-free devices.
  • The work will result in an update of the new Recommendation on "Subsystem Requirements for Car Hands-free Systems", in a new Recommendation "Performance Requirements for In-Car Communication Systems" and in a new Recommendation "User Interface Requirements for Automotive Applications".

An up-to-date status of work under this Question is contained in the e SG 12 work programme



  •   P.340, P.313, P.501, P.502, P.581, P.582, P.ONRA


  • 3/12, 5/12, 6/12, 9/12

Study Groups

  •  ITU-T SG 16

Standardization bodies

  •  ITU-R, 3GPP SA4, 3GPP2, ETSI STQ, ETSI ITS, Bluetooth SIG, ISO TC 22/TC 204