New Algorithm Optimzied for Mobile Devices

Researchers at Penn State University have developed an algorithm thatlets users of cell-phone and other mobile devices pick up data that may have been "missed" when first broadcast. And because it minimizes channel switching, the algorithm also leads to reduced power use, thereby extending battery life.

According to Prasenjit Mitra, an assistant professor in the College of Information Sciences and Technology (IST) "cell-phone users don't have to wait for fewer broadcast cycles to retrieve the data as the mobile device can pick up objects broadcast across parallel air channels."

Mitra, graduate student Padmapriya Ayyagari, and professor of computer science Ali Hurson, say that data dissemination for mobile devices now occurs through one of two techniques:

• Unicast, which is common when data is sent to a single person.
• Broadcast, when data is sent to multiple people over parallel air channels.

While broadcast is more common when the same content such as emergency alerts, weather information or television shows reaches multiple people, the typical algorithm currently used can't take advantage of data that is broadcast repeatedly on different channels. Instead the data has to be broadcast in cycles. This wastes both time and power.

"If you can retrieve all the data you want in fewer broadcast cycles, then the user saves on time and battery power," Mitra said. "The power-consumption reduction is achieved because the technique fetches all the objects requested by a client while minimizing the number of channel switches required."

As part of their study, the researchers developed and compared the performance of the four kinds of algorithms--greedy, random, branch-and-bound, and select first--that could be used to improve object retrieval and reduce power consumption. Of these, the researchers' greedy algorithms created an efficient and quick solution to object retrieval that also decreased battery drain.

Posted by Jon Erickson at 12:17 PM  Permalink