Sunday, October 16, 2011

Wanted: Haunted Vehicles

Halloween is just around the corner, and that reminds me of the haunted room at Lucent Bell Labs. Mind you, it wasn’t really haunted. But for a moment, I was convinced.

Let me explain. As I entered the room, I could hear two of my colleagues talking to each other, and by the sound of their voices, they were both sitting right in front of me. But when I looked, I could see only one person. Creepy, to say the least.

It took a few seconds, but I finally realized what was happening: The other colleague was in a different room, talking over a perfectly tuned prototype of a conference phone. The sense of presence was so real that I couldn’t help but feel we were all in the same room — even after I became aware of the “trick” being played!

It was then that I realized it: We don’t know what we’re missing until we experience it.

Making it real
Current telephone calls don’t sound like face-to-face conversations because the telephone network and terminals band-limit speech from about 50-10000 Hz down to 300-3400 Hz. To make matters worse, the phone’s single channel of audio eliminates spatial information about the sound source. As a result, we perceive most sounds as coming from the same point in space.

But here's the thing: The historical reasons for transmitting these single-channel narrowband speech signals no longer apply. Current technologies — such as wideband speech coders, spatial audio, and VoIP — are enabling speech communications with wider bandwidth speech and greater spatial information.

Many in the industry refer to these next-generation telecommunications systems as telepresence systems. “Telepresence” refers to the degree of realism created by a telecommunications system. Traditional systems have low telepresence while newer systems that use wider bandwidth speech and spatial audio have high telepresence.

Some people believe that a visual display is a must-have for a telepresence system. In reality, a display can decrease telepresence if its quality is poor. Experience shows that an audio-only system can have such high telepresence that people can't distinguish it from face-to-face communications — witness my haunting experience at Lucent Bell Labs.

Until recently, widespread deployment of telepresence systems has hit a roadblock: lack of standardization. Fortunately, the IETF CLUE Working Group and ITU-T Study Groups 16 and 12 are actively developing standards to remedy this situation.

Pimp my ride with telepresence
Telepresence systems have a lot to offer in an automotive environment. For instance, they could:

  • reduce driver distraction
  • make it easier to understand speech in the presence of vehicle noise
  • reduce the fatigue that comes from trying to understand a degraded voice signal

Moreover, a telepresence system makes the talker on the far end of the phone connection sound more like they are in the vehicle; it also makes the talker easier to identify.

Successful deployment of telepresence in an automotive environment depends on several factors:

  • attention to the design of vehicle platforms
  • use of high-performance acoustic processing algorithms (AEC, NR, etc.), such as those provided by the QNX acoustic processing suite
  • the ability to transport telepresence signals between telephony terminals — this is being enabled by increased VoIP availability (via LTE, for instance)

I don't know about you, but I'm looking forward to the day when my vehicle is haunted like that lab in New Jersey!

For additional reading on this topic, download the whitepaper, "Wideband Speech Communications for Automotive: the Good, the Bad, and the Ugly".


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