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Professor’s algorithm may lessen stress on wireless networks

Though the wireless spectrum may seem infinite to mobile device users, in reality, our devices continue to tax it to near capacity. MU electrical and computer engineering Professor Dominic Ho, however, has developed an algorithm that potentially could take some of the burden off the wireless spectrum.

Dominic Ho head shot.

Professor Dominic Ho developed what’s called an underlay to allow users to utilize other users’ bandwidth who don’t currently need it instead of using bandwidth from the spectrum itself, thus optimizing the experience for both users.

Ho and doctoral candidate Mohannad Al-Ali, a participant in the College of Engineering’s HCED Iraqi Program, wrote “Transmit Precoding in Underlay MIMO Cognitive Radio with Unavailable or Imperfect Knowledge of Primary Interference Channel,” which recently was accepted by IEEE Transactions on Wireless Communications, a journal of the Institute of Electrical and Electronics Engineers.

The algorithm they developed uses what’s called an underlay to allow users to utilize other users’ bandwidth who don’t currently need it instead of using bandwidth from the spectrum itself, thus optimizing the experience for both users.

“In engineering what we try to do is we look at the physical limitations and see how much we can squeeze out of that,” Ho said. “It’s like a water pipe. The diameter is only so big. You can only push so much traffic through.

“What we tried to do is steal some opportunity to do transmissions that’s hidden to the primary user. If you are the primary user, they can steal some of your bandwidth, and you don’t know about it. This is a smart way to squeeze something more out of our resources.”

The algorithm sets limits on the amount of interference allowed to the primary user before the secondary user is redirected toward back to the wireless spectrum. The research also illustrates that using multiple-input multiple-output (MIMO) antennas reduces the amount of interference from the secondary user and allows both users to maintain the quality of service to which they’re accustomed.