Wireless Research May Mean the Difference Between Life and Death

Wireless Calls Can Be Pinpointed Down to 15 feet for Emergencies

Murray Hill, N.J. (August 1999) -- Assume a victim of an accident on a remote stretch of highway manages to press 911 on his cell phone, but is unable to speak. Rescue crews know the caller is in trouble but can waste precious time locating him.

In such a situation, quickly pinpointing the victim's location can mean the difference between life and death.

Until Bell Labs tackled the problem, cellular telephone technology deployed today could pinpoint a wireless emergency call down to only a three to six square-mile area. Trying to locate a human being in an area that large is the equivalent of searching for a needle in a haystack.

Closing the Gap

All that is about to change in the United States, thanks to the ingenuity of wireless researchers from Bell Labs, who have developed the most sensitive technology yet for determining the location of wireless 911 emergency calls.

Giovanni Vanucci (foreground) and (l-r) Bob Richton, Ren Da, and Tung Ching Chiang illustrate the accuracy of technology that allows cellular service providers to pinpoint a caller's location down to 15 feet -- the distance between the researchers.

The Bell Labs geolocation approach is based on Global Positioning System (G.P.S.) satellite data. The approach, called Wireless Assisted G.P.S. (W.A.G.), is accurate to within 15 feet when users are outdoors. Fifteen feet -- a little more than the width of a traffic lane -- is a distance easily scanned by the human eye.

Once the technology is deployed, it will provide precise location information to police, and will be especially helpful when callers are unfamiliar with their whereabouts. Rescue teams responding to a wireless emergency call will no longer need to search to locate an accident site.

The Bell Labs geolocation approach is accurate to within 100 feet when a wireless phone is indoors. Using current wireless systems, it is impossible to locate a wireless call made from within a building.

Pursuing Geolocation Standards

"We intend to pursue standardization of this geolocation technology so that it can be widely and inexpensively deployed," said John Freidenfelds, director of wireless technology applications at Lucent's Wireless Networks Group.

Lucent and Qualcomm, a leader in digital wireless CDMA technology, signed an agreement in July to develop and promote Bell Labs geolocation technology.

FCC Wanted a 410-Foot Radius

The driving force for the research has been a U.S. Federal Communications Commission mandate that recognizes the need for geolocation and says that, by October 2001, most wireless 911 calls must be pinpointed to within 410 feet.

Even before the ruling, Giovanni Vannucci of the Wireless Communication Research Department had begun thinking about the problem. He realized that it was possible to use G.P.S. satellites to pinpoint wireless telephones making calls.

G.P.S. satellites encircle the globe and are used to provide navigational information to military and civilian users. Originally developed by the Pentagon, many civilian uses for G.P.S.-based devices have been developed, from aircraft landing systems to measurements of golf shots.

G.P.S Posed Problems for Wireless 911

Up to now, G.P.S. was considered unsuitable for wireless 911 applications because devices based on G.P.S. signals were too slow for emergency use, consumed a lot of power, and were too costly or too bulky to include in a mobile handset. Also, they did not work inside buildings or shadowed environments like the concrete canyons of New York.

Vannucci teamed up with Bob Richton of the Wireless Technology Laboratory to find a way to circumvent these problems. They came up with the W.A.G. method, which makes use of a mobile phone with a scaled-down G.P.S. receiver. The mobile receiver picks up signals from some of the G.P.S. satellites that are simultaneously seen by a reference G.P.S. receiver connected to the wireless network.

The Network Helps Relay the G.S.P. Info

The network sends G.P.S. information it has picked up to the mobile handset, which uses this information to detect G.P.S. signals from the satellites. The mobile handset then returns data about the signals it received to the network, where it is used to compute the handset's location.

"The reason the mobile phone can manage with only a partial receiver," said Vannucci, "is because of the help it gets from the wireless network. The network's receiver can provide some complementary information."

Ren Da (left) and Richard Leung discuss their wireless 911 demonstration in Whippany. They represent the Wireless Technology Lab on a cross-unit development team.

Since the calculation of the exact position is done within the network, the handset doesn't need to be complex and expensive, said Richton. Once the potential of the idea was recognized, a cross-unit team was set up to implement it. Vannucci and Richton were joined by Ren Da, T.C. Chiang and Richard Leung of the Wireless Technology Laboratory, part of Lucent's Wireless Network Group.

Technology Being Integrated into Existing Products

Work progressed quickly. Several new algorithms were designed to maximize calculation efficiency, a prototype was built and a demo set up. A team of system engineers at Indian Hill is working to determine how to integrate the technology into existing wireless network products.

Chiang, who acts as the project manager, said, "We are all very excited about the work being done and hope to see the technology become a real product as soon as possible."

He added, "This is a successful story not only in creating new, profitable technology for Lucent, but also in collaboration between Research and business units. Without such teamwork, we would not be able to produce such excellent technology."

Precise Pinpointing Promises Many Applications

There are many potential commercial applications of geolocation technology. For example, pinpointing a customer's location could yield such services as detailed driving directions and local traffic information, especially when combined with improved data services expected two years from now.

"I started my career in military research, and, although that work is also needed, it's personally much more rewarding to work on something that will lead to devices that help people," Richton said.

The Bell Labs approach works with all of today's global digital networks and will be compatible with next generation broadband wireless networks, which will provide a broad assortment of location-based services, as well as high-speed, Internet-based multimedia services.

Chiang said that he hopes it will not be too long before all the major cellular service providers use W.A.G. "The immediate next step is to try the technology with some of our major wireless customers who are very eager to have a trial with us," he said. "Then, eventually, when the product is developed and standards are in place, they will be using W.A.G. to locate a cellular phone caller."

This information is based on an article written by Bell Labs Public Relations.