Communications of the ACM
Faster Internet on the Road
The R2D2 relay device will appear in the 7th International Conference on Mobile Systems, Applications, and Services.
ACM 2009
Researchers at Rutgers University's Winlab and NEC Laboratories have developed R2D2, a system designed to improve Wi-Fi wireless Internet access when traveling. R2D2 features special antennas and software that integrate directionality and diversity wireless techniques to maintain an Internet connection.
Directionality involves focusing all of the radio energy from an antenna in a single direction, which increases the average signal strength but can cause the connection to fail when the base tower is out of range. Diversity spreads the antenna's signal equally in all directions to reach as many base towers as possible, which minimizes signal loss but weakens the signal. "You have to hit the sweet spot in between these two extremes," says NEC researcher Kishore Ramachandran. The system determines how much to widen or narrow its antenna beam, and can warp the signal into multiple lobes, if necessary, to reach the base stations.
To sustain a high-quality signal, R2D2 continually switches base stations as the vehicle moves out of range. Rutgers University researcher Dipankar Raychaudhuri, who was not involved in the R2D2 project, says a benefit of the proposed scheme is that it works well with existing Wi-Fi and vehicular radio standards.
"R2D2 shows that it's better to focus on the middle path between [directionality and diversity]," says Microsoft researcher Ratul Mahajan. "They did a good job of showing that this is one way to do it that is practical and brings significant gains."
From Technology Review
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