Researchers tackle the vehicular network

That's the question distributed computing researchers from MIT, Georgetown University the National University of Singapore are trying to answer, and it's a doozey of a problem. A distributed network of cars is by definition ad hoc - the vehicles are constantly moving in relation to one another. They're forming new W-Fi connections during breaking old ones, changing their positions within the network or leaving the network utterly. Trying to get these mobile and unpredictable nodes to cooperate is going to be difficult.

Network out of freeway chaos

But MIT graduate student Alex Cornejo said math can be used to used to wrestle just such a network out of freeway chaos. He and his colleagues have developed an algorithm that would allow hundreds of different cars to aggregate their internet-bound data and send it compressed over a single cellular connection, along these lines reducing bandwidth costs for all the vehicles participating.

The process starts with two cars in Wi-Fi range, both hoping to establish an internet connection to download content, send email, upload documents or some other action. One car passes its data along to the other, which is at first determined randomly, however as the vehicles move throughout the network patterns start emerging. Those patterns determine which vehicles become aggregation nodes for the network, Cornejo said.

When any given car has aggregated enough data, it establishes its cellular connection, uploading aggregated data to the internet or downloading data, which it at the time distributes back through the same ad hoc network, Cornejo said. The amount of time spent aggregating is determined by the type of data, he added. Files with a longer shelf-life, like e-mail could be passed back and forth between hundreds of vehicles earlier it exits the network. Real-time applications would have far less tolerance for delay, however he said it would be possible for two vehicles making VoIP (Voice over Internet Protocol) calls or video chat sessions to share a single cellular connection.

In theory, a fleet of 1,000 cars could see all of their data aggregated into just five cellular links, even accounting for cars that right away break from the network taking their stored up data with them, Cornejo said. The key is for algorithm to define distinct clusters of cars among seemingly random traffic patterns. If the distinctions between those clusters start breaking down, just as one platoon of traffic crosses paths with another, at the time the whole system breaks down.