Cars Create Wireless Network

June 8, 2007 —Hotspots. GPS. Internet-enabled phones. The world is going wireless. And a group of researchers are extending the concept to the car, turning automobiles into network nodes that can receive and send signals to others nearby.

As car after car enters the mobile network (some eventually drop out of range), drivers can download multimedia — including movies, images and songs — or get real-time information about traffic.

"Say you are driving and a car that is three miles in front of you spots an icy spot on the road. It can trigger back a signal saying, 'Look, there is an icy road,'" said Giovanni Pau, research scientist at the University of California's Network Research Lab in Los Angeles, which is led by Mario Gerla.

Such a network could also give emergency first responders a reliable channel if a natural disaster destroys communication towers or access points.

The system uses a vehicle's onboard computer, GPS, low-cost sensors, custom software written by the UCLA team, and existing wireless channels.

In recent experiments, the researchers used the standard protocol that allows laptops, for example, to connect wirelessly to the Internet. The typical range is between 330 to 990 feet.

In the near future, vehicles will switch to the Dedicated Short Range Communications standard being developed by the Department of Transportation. This signal, which has a range of up to 3,300 feet, will allow high-speed communications between vehicles or between vehicles and the roadside.

The software written by the UCLA team locates its own car and the cars it wants to talk to, selects the strongest signals, determines if any of the drivers should have priority (emergency workers might, for example), and organizes the various data being exchanged.

For now, cars within a couple to a few hundred feet of each other can exchange data, but the information can hop from one car to the next across the entire network, which could span miles.

If a car needs information directly from the Internet, it does need to access a fixed communication tower or hotspot — or it must talk with other cars that have accessed the Internet. Just last week, team members drove around the Los Angeles area to determine how many open access points a car could tap into at any given time. They discovered that there were, on average, 30.

But if a driver is looking for a movie or map already stored on another vehicle's computer, no access to the Internet is needed.

"In some applications a car just needs Internet content, say a local map or picture…then, the car can get the data secondhand from another car that was earlier connected to the Internet and happened to have downloaded that map or picture," said Gerla.

Other groups are also working on mobile networks, but Pau and Gerla see three main advantages to their approach.

First, thanks to a collaboration with the Los Alamos National Laboratory in New Mexico and the Istituto Boella in Torino, Italy, the UCLA researchers can simulate realistic traffic scenarios on a very large scale and can thus fine-tune the software based on such models.

They are also testing distinct types of mobile network patterns, such as those designed specifically for emergency workers.

But other mobile networking groups will still benefit. The group will be opening up their test bed to the scientific community at large, giving other research groups the opportunity to test their own applications.

"Automakers have their own simulations, but these simulations are internal and it's very unlikely that they would be made available to the academic community," said Liviu Iftode, associate professor of computer science at Rutgers University in Piscataway, NJ.