Subject: [NEXTEL-1] Future cell phones to see the light- Optical CDMA signals

From: Marcel <[email-masked]>
Date: Mon, 02 Dec 2002 14:37:59 -0500

Future cell phones to see the light
By Sandeep Junnarkar
Special to ZDNet News
November 27, 2002, 7:08 AM PT
URL: http://zdnet.com.com/2100-1105-975549.html

The University of California at Davis announced this week it has received a grant from
the Defense Department to build a new generation of cell phones that transmit and
receive optical signals.

The optical cell phones could make wireless communications speedier and more secure than
existing optical fiber networks, researchers said.

U.C. Davis will share the $5 million, four-year grant from the Defense Advanced Research
Projects
Agency (DARPA) with the Lawrence Livermore National Laboratory.

The researchers hope to build chip-sized devices that use a technology standard already in
some
cell phones. That technology, called Code Division Multiple Access (CDMA), transmits and
receives
optical signals. CDMA, which runs about 20 percent of the world's wireless networks, is a
proprietary
standard. Qualcomm owns the patents.

A different technology in widespread use employs a method called wavelength division
multiplexing,
in which each cell phone uses a different wavelength of light, according to the
researchers. In contrast,
optical CDMA would encode each pulse, or bit of information, across a segment of
wavelengths. The
receiver uses a key to decode the signal and re-create the original pulse.

"Security-wise, there are strong advantages to optical CDMA because you can change the
code at
any time," U.C. Davis electrical engineer Zhi Ding said.

Some cell phone systems, such as those from Sprint PCS and Verizon Communications, already
use
a type of CDMA for radio waves, according to the researchers.

The optical CDMA project is part of the California Institute for Information Technology
Research in the
Interests of Society (CITRIS), which is a coalition of U.C. campuses and industry
partners. The
organization's goal is to apply technology to aid in emergency response, natural disasters
and
environmental monitoring.

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

---

From: Jack Daniel <[email-masked]>
Date: Mon, 02 Dec 2002 12:13:41 -0800

Can you see me now?............ Can you see me now?...........

==================================================================

Marcel wrote:
>                    Yahoo! Groups Sponsor
>                        ADVERTISEMENT
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.