ITS:Cell Phones as transponders

Transponders we were told could be part of something called Electronic Tolling and Traffic Management (ETTM). Toll tags have been read in a few limited stretches of highway in Houston, the northern NJ/New York area and San Antonio TX to generate data on traffic speeds for incident management centers. But with the imminent mandate (10/1/01) by the FCC that wireless phone companies be able to locate callers when they call 911, the technology is being developed to use cell phones as traffic probes. And eventually as toll transponders?

And there are a lot more cellphones out there than toll tags – in the US about 80m vs 6m. The cellphone location finding equipment is starting to be deployed. US Wireless Corp of San Ramon CA is doing a 3 month test on the Washington DC Beltway. And it is part of a team that will use several technologies to provide traffic data services in the Hampton Roads VA area.

Like the best newsletter publishers, the guy who founded US Wireless in 1996 is an immigrant, Oliver Hilsenrath, an electronics engineer from Israel who settled in the San Francisco Bay area and has recruited senior staff from AT&T, British Telecom and other companies.

Various techniques are being used to do cellphone location finding for the FCC E-911 mandate, many using triangulation to work out the direction of the signal from two or more points. US Wireless however has a patented system it calls RadioCamera(tm) which uses pattern recognition from a single antenna site to determine the location of various cell phones in use.

RadioCamera works off a reference library of locations according to the unique multipath signal bounces that develop at each because of the special configuration of buildings, topography and other physical features that influence the paths of the radio waves of the cellphones. USWC calls this library of multipath characteristics its Pattern Matching Database. The system of antennas then pick up the signals of operating cellphones and refer acquired signals to the database in order to make a match and identify the location of each cellphone. By tracking the movement of individual cellphones and continuously updating their location it can estimate traffic speed. Various moving cellphones are followed and speeds averaged to gain average speed data for various segments of roadway.

US Wireless has signed testing and product evaluation agreements with leading wireless carriers, including Bell Atlantic Mobile, Western Wireless, GTE Wireless, and Nextel. There are deployments and ongoing field trials in Oakland CA, Billings MT and soon in the Washington DC area. It is raising money and developing agreements to deploy networks covering the hundred top metro areas over the next 18 months investing over $500m in equipment and setup.

The RadioCamera(tm) system is being adapted to the various north American wireless industry standards, including analog AMPS, and time and code division multiplexed digital mobile phones including iDEN, and the European GSM. The equipment consists of antennas similar to cell phone system antennas but passive, usually co-located on cell phone towers, plus standardized signal processing equipment similar to an industrial-grade PC. The patented technology is the signal processing software plus the developed reference database of multipath patterns that identify different locations.

Rick Weiland, a veteran ITS guy in Chicago, says that the success of something like RadioCamera will depend on its accuracy and its cost versus other sources of information. It will compete to some extent with in-pavement loops, toll tags as probes as well as radar, laser and machine vision gear. Not to forget the brilliant aerial photography of traffic as performed by Skycomp. The FCC requires accuracy 67% of the time to within 90m. US Wireless thinks it can do considerably better than that. Statisticians will be able to work out how much accuracy is enough. (One can imagine serious problems distinguishing traffic on free I-295 and on the turnpike in southern NJ!)

Like most technologies it is certain to have areas of weakness.

US Wireless hopes to go beyond just generating data for incident management centers and to get traveler information services to motorists via their cell phones. Weiland says gadget overload is a real problem, people juggling handhelds, cell phones, pagers, laptops. There is a powerful logic in adding data and reference functions to cellphones rather than adding another device with a screen to the car. So why not offer navigation data so the cellphone can be programed to help you find your way with one of those synthetic voices and arrows on the phone’s display. Then unlike the distracting $1,000 contraption in a Hertz rental car you could use your mobile direction-giving on foot as well.

And at US Wireless the investor relations person Paul Brunato says cell phones could be configured to function as toll transponders with programming to send a toll account number to the tollster via the cell phone company when the RadioCamera type technology detects the user going on a toll road. The toll might be billed via the cellphone company. This could solve the problem of the occasional user to whom it is expensive and difficult to supply a regular toll transponder and to track through license plate imaging and motor vehicle registry referencing.

Wireless phones are getting so cheap and handy they are not far from becoming as common as wired phones. Once emergency services location finding is in place by late 2001 and perhaps 110m ‘mobiles,’ as the Europeans call them, are in use in the US, there will be the infrastructure to do a lot of road pricing without having to issue single purpose transponders.

Of course someone would have to work out a way of distinguishing between a driver with a cellphone in a car in creep and crawl traffic and a pedestrian with a cellphone in his pocket on a sidewalk nearby. But then toll transponders get some pretty screwy reads too... (Contact Paul Brunato USWC 925 327 6200 paul@uswcorp.com, Rick Weiland 847/864-0908 rweiland@wwa.com)