Amanda sits idly at the bar of the trendiest restaurant in town, twirling a swizzle stick and sipping a cocktail. But cool as she looks, she’s feeling anxious: her date is nearly 15 minutes late. She considers calling him but doesn’t want to seem nervous or overeager. Still, she pulls out her cell phone, only instead of calling, she opens a special menu, enters his number, and sees that he is at the corner of Prospect and Broadway, not more than three minutes away. When he walks in, Amanda brushes off his apology, saying she wasn’t at all worried.
You Are Here
Location-finding technologies have taken root in Europe and Asia (see “Location’s Rising Sun,” sidebar) due to the convenience they offer, but the driving force in the United States has so far been safety. Six years ago, the Federal Communications Commission mandated that cellular carriers be able to automatically locate anyone making an emergency 911 call. Carriers must be able to locate callers to an accuracy of 50 to 100 meters (depending on the technology used) by December 2005. “Hundreds of millions of cell phones have to have location awareness by law. That’s a huge technology driver,” says Larry Smarr, director of the California Institute for Telecommunications and Information Technology, which is helping develop, among other things, the next generation of wireless technologies.
Tracking users becomes much more challenging indoors, however. Assisted GPS can lose much of its accuracy due to ceilings, walls, and other obstructions, while cellular techniques don’t even come close to making the grade: a 120-meter error range may let you spot a flashing restaurant sign down a city block, but even a five-meter miss in a skyscraper could put a user on a completely different floor. Although this isn’t an issue in many applications, it could mean the difference between life and death to soldiers trying to identify friends and foes in an urban warfare setting or firefighters searching for victims in a blaze.
So what kind of technology could be used once a person steps inside and takes the elevator up, up, and away? One possibility is the popular wireless networking technology known as 802.11, or Wi-Fi. Numerous wireless carriers have begun installing Wi-Fi transceivers in hotels, cafs, and other commercial buildings to deliver high-speed Internet access to mobile users. This expanding infrastructure can also be used to locate people indoors, says Antti Korhonen, CEO of Helsinki, Finland-based Ekahau, which builds software that enables Wi-Fi location finding. This past spring, consulting firm Accenture used Ekahau’s software in a pilot project for New York’s Metropolitan Museum of Art: patrons wandering the Met’s cavernous halls and stopping at a few of its two million works of art received information about the pieces in front of them with the click of a PDA button.
To achieve this virtual docent delivery, Accenture employees drew a detailed map of the exhibit area-a process that can take an hour for every 1,000 square meters covered, says Korhonen. Once the map was uploaded into a computer, employees walked around the museum, clicking on the map every three meters and recording the network’s signal strength. Each location was matched to a specific signal strength, so that when museumgoers accessed the network, it knew where they were. With accuracy ranging from one meter to 20 meters, says Korhonen, Wi-Fi mapping is generally more precise than cellular triangulation. Big commercial applications will begin to emerge this year, he says; for instance, a German retail chain is using Wi-Fi in a pilot project to push information to shoppers depending on their location in a store. Since devices on the first floor of a building will measure significantly different signal strengths than those on other floors, Ekahau’s technology can also solve the up-down problem, says Korhonen. “There is no way we could miss the floor,” he says.
If location is calculated based solely on which Wi-Fi access point is closest, though, and not on painstakingly assembled signal-strength maps, the technology often places people on the wrong floors. And whether used indoors or out, a Wi-Fi transceiver covers a limited geographical area, with a radius of only about 90 meters. It’s also susceptible to signal interference that can affect accuracy and is not particularly secure: nefarious characters might be able to determine your location based on your signal. According to Bill Yeager, a Sun Microsystems engineer working on location-aware computing, someone who knows that you are in a pizza place rather than at home could say, “Let’s go over there and steal his home theater, or whatever they want to take.”
It’s not hard to imagine applications that will require greater accuracy, not to mention reliability and security. Luckily, another wireless technology could fill the gap: ultrawideband. Ultrawideband uses on/off energy bursts only billionths of a second long at extremely low power (one-thousandth the power of a traditional cell phone) over a large frequency spectrum. These tiny bursts enable the technology to deliver data at speeds of hundreds of megabits a second, as well as provide ultraprecise positioning. And as with GPS or Wi-Fi, ultrawideband could be incorporated into a cell phone or PDA.
Distance can be determined by measuring how long it takes a pulse to travel between an ultrawideband transmitter and receiver, and position can be determined via triangulation if at least three signals are received. “If you have four locations, you can do vertical mapping,” says Bruce Watkins, president and chief operating officer of Pulse-Link, a San Diego-based ultrawideband company. That enables the system to figure out how high an object is off the ground-or which floor of an office building or hotel a person is on. Because the technology-unlike Wi-Fi-relies on ultrashort pulses, the receiver can determine time of arrival in picoseconds, allowing it to establish location to within centimeters, according to Watkins. Yet because ultrawideband is not as far along in its development and deployment as Wi-Fi, ESRI’s Spinney, for one, sees it losing out on many applications, such as tracking consumers through malls or airports-where Wi-Fi systems are already being installed-and sending them promotional offers.
The Perfect Hand-Off
In an ideal world, a cell phone or PDA would seamlessly switch from, say, GPS to Wi-Fi when its user walked indoors, providing continuously updated location information. In the real world, though, the pieces still don’t quite fit together. “We have a whole tool chest of location technologies, but what there isn’t is a unified go-anywhere approach,” says Smarr of the California Institute for Telecommunications.
Generally, the problem isn’t technological: Wi-Fi and cellular radios, for example, can be integrated into a single device. Symbol Technologies, a Holtsville, NY, mobile-computing company, has developed a handheld for UPS that can access both types of networks. The difficulty lies in setting up service plans and contracts that will allow users to get location-based services as they move from outside to indoors. Cellular and Wi-Fi integrator Transat Technologies, in Southlake, TX, and Gemplus, a leading smart-card company based in Luxembourg, have begun to tackle the problem with special software embedded in smart cards. As carriers start to offer both Wi-Fi and cellular services, mobile users will be able to plug these cards into their cell phones and get access to both types of networks-and, presumably, all the location-based services they make possible.
In the shorter term, however, an even bigger problem looms: what if callers want to access location-based services using multiple cellular networks, say, AT&T Wireless and Sprint PCS, as opposed to a single carrier’s combined Wi-Fi/cellular network? Software standards that will allow callers to use location-based services across the two main U.S. cellular technologies (which are known by the acronyms CDMA and TDMA) were expected to be ratified by this fall, according to Paul Hebert, a senior product manager at Redwood City, CA-based Openwave Systems, which sells location-based applications to carriers. Similar roaming standards for GSM, the world’s other major wireless standard, could be approved next year, he says. The lingering question, though, is whether carriers will share their services with other companies’ customers. “For location services, it is the business issues that need to be resolved,” not technological ones, says Hebert.
On the assumption those business issues can be resolved, Intel is pushing to enable even greater interoperability across technologies. While the proposed standards would allow callers to use location-based services offered by different cellular networks, Intel’s idea is to let them switch just as effortlessly between cellular, Wi-Fi, and ultrawideband networks. Intel’s “location stack” system will also be able to compensate for the imprecisions of the various technologies to yield more exact position information, says Gaetano Borriello, director of Intel Research Seattle. “The reason we are pushing the stack model is to keep [location finding] independent of a specific technology,” says Borriello. “We want to provide the infrastructure that will allow others to experiment and find those killer apps.”
Once the location-finding infrastructure and standards are in place, experts say, the U.S. market for location-based services will take off. Offerings will, no doubt, include friend and noodle finding, but a variety of other services are in trials or still on the drawing board. While everyone has a best guess as to what the real killer location application will be, they remain just that-guesses. “There are going to be things that just pop up,” says Borriello.
At their core, the winning services will give people information that improves lives and saves time, or as ESRI’s Spinney puts it, that “predicts the unpredictable”-enabling, for instance, easy navigation around traffic accidents or street closures. Because outdoor location-finding technology is more mature, services such as friend or restaurant finding have been offered first. But carriers see these as just the first wave of a variety of location-based services that “they can sell to drive revenue,” says Arnold Gum, a Qualcomm senior product manager whose job is to figure out how new technology can help the world’s wireless carriers make more money. In some cases, customers will be charged by how much data they consume: users of AT&T’s friend finder service, for example, pay $2.99 a month plus usage charges, which depend on how many friends they ping. In other cases, consumers will be charged a set fee for each application.
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