New technique could prevent cell networks going down in disasters

Television and radio channels could be used to transmit phone signals when systems are pushed beyond capacity in natural disasters, a Canadian researcher says. Cellular networks can be quickly overloaded when a natural disaster strikes and too many people take to their mobile phones at once, University of British Columbia doctoral student Mai Hassan said. "I proposed a more effective way to use any channel in the neighborhood, even if those channels are being used by radio or television stations," she said. "The challenge was finding a way to make sure the cellular signals didn't interfere with the people using those channels in the first place." Her solution to ensure calls don't get dropped and texts make it to their destination involves changing the shape of wireless signals so they can be transmitted on channels that use radio or television frequencies without interfering with signals already on those channels. Smart antennas in mobile phones can transmit signals in a single direction and can steer the beam to any direction, Hassan said, and by manipulating the direction of the cellular signals it is possible to transmit calls and texts to a receiver while avoiding any interference with the original radio and televisions signals. Hassan's study has been published in the journal IEEE Transactions on Wireless Communications.