Future cell phones to see the light

U.C. Davis gets a Defense Department grant to develop a standard for a new generation of cell phones that use optical signals for speedier and more secure communications.

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

The new standard for 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 eventual aim is to create a cell phone that can connect to the fiber-optic backbone through optical, rather than electronic networks.

The researchers said the new technology would be built on a standard already in use in some cell phones. The older 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.