NTT Develops Wristwatch PHS

NTT PHS wrist phone

     No, that guy on the corner isn't necessarily holding a conversation with his
           wristwatch. From NTT comes a lightweight, compact, voice-activated
           PHS unit that you can strap to your wrist.

           by Noriko Takezaki

       The US may have taken an early lead in the development of "wearable
       computers," acknowledges NTT (Nippon Telegraph and Telephone Corp.), but
       that is not the case when it comes to wearable communications tools. To prove
       it, NTT has announced a wristwatch-type PHS (personal handyphone system)
       unit featuring a voice-recognition dialing function so that the user can place a
       hands-free call.

       "The Japanese are good at producing very compact and sophisticated tools,"
       says Tetsuma Sakurai, senior research engineer at NTT's Speech and Acoustics
       Laboratory. "So there is high potential that Japan can lead the world in the field
       of wearable communications devices."

       A "wristwatch" PHS unit
       NTT's compact "wristwatch" PHS unit (also available with a necklace pendant
       case) contains an embedded LSI chip and miniature lithium-ion battery; it
       weighs just 45 grams. The user can activate the unit's hands-free voice-dial
       function by preregistering the phone number to be dialed with his or her own
       voice into the PHS memory. The unit's dialing function is then activated by
       announcing either the number to be dialed or its associated registered name,
       such as "uchi" (my home) for the user's home phone number, into the PHS

       According to NTT, the unit's voice recognition function can handle any
       language, so long as the voice-dial registration was done in that language. The
       PHS also supports pushbutton input of abbreviated (quick dial) numbers.

       NTT's Sakurai says that the key to the unit's success lies in its LSI chip, which
       enables high voice recognition performance and suppression of howling (noise
       picked up by the microphone from the unit's speaker), as well as low power
       consumption and low cost. "The voice recognition precision of this PHS unit is
       quite high," he claims; "more than 95% precision in a quiet indoor setting, and
       70% to 80% even in a noisy outdoor environment."

       The LSI consists of an MT-CMOS (Multi-Threshold Complementary
       Metal-Oxide Semiconductor) device and incorporates two transistors with high
       and low threshold values. The transistor with the higher threshold functions as a
       barrier against current leakage during circuit idling, while that with the lower
       threshold is used during normal operation. This helps reduce the device's power
       consumption and enables the unit to support calls of up to 60 minutes duration
       or to function for 100 hours in standby (call-available) mode.

       With the cooperation of a semiconductor manufacturer (Sakurai would not
       disclose the name, saying only that NTT had evaluated both foreign and
       Japanese RISC chip manufacturers), NTT spent one year designing and
       developing the requisite LSI. Sakurai recalls that the critical point in selecting a
       chip manufacturer was not the performance of the chips themselves, but the
       availability of an evaluation toolkit (including simulator, emulator, in-circuit
       emulator, and target board) to assess the application development work at
       NTT. Even though some companies offered chips with excellent performance,
       few offered an adequate evaluation tool kit, notes Sakurai. "This is something
       that semiconductor manufacturers should seriously consider [to extend their
       market share]," he says.

       An Olympic field test
       NTT has a long history in voice recognition R&D, dating from the early 1980s.
       NTT researchers were confident, therefore, of their level of technology; they
       were not so sure, though, about the commercial application of this technology to
       a wearable PHS unit. The basic question was whether people would be willing
       to speak into a wristwatch PHS in public.

       For those too shy to speak loudly into the wrist unit, NTT developed a compact
       earphone-type microphone/receiver. The optional earphone unit features
       separate microphones for better voice transmission -- one that picks up the
       user's voice normally through airborne sounds, and one that picks up voice via
       conduction by the speaker's facial bones.

       During the product's field trials, carried out at the Nagano Olympic Games site
       in February, NTT was pleased to find that the number of people willing to use
       the wristwatch PHS unit far exceeded its expectations. Moreover, few of the
       field trial users bothered to employ the optional microphone/receiver unit.

       Sounding out the future
       NTT is the first to apply voice-recognition technology to a wearable PHS unit.
       It is too early to say, though, whether PHS will be a key player in the wearable
       communication device market of the future. That shouldn't pose a problem,
       since the technology can be easily applied to cellular phone systems as well.

       The main reason that NTT selected PHS to showcase its voice recognition
       technology at this time was in part to widely promote PHS, including at the
       Nagano Olympic site where the field trials were conducted. NTT is eager to
       improve the image of PHS, which has often been criticized for poor
       performance and connectivity, and thus help its money-losing PHS affiliates.

       NTT says that its target for commercialization of a voice-activated PHS unit is
       two years. For successful market release, however, the product still requires
       some improvements, such as cost reduction to the level of standard PHS units
       (in the 20,000 range) and an improved terminal design that offers easy
       operation (current button operation remains slightly complicated). NTT's
       voice-recognition technology is first rate, but high quality

       Technology alone doesn't sell products. Ultimately, the most important factor
       for successful sales of NTT's wristwatch PHS will be the short-and long-term
       success of Japan's PHS market..


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