October 14, 2013
A Novel Solution For Overloaded Cell Networks
Brett Smith for redOrbit.com - Your Universe Online
Smartphones are ubiquitous in 2013 – making anyone capable of quickly reporting an accident or getting information via voice, text or data. However, that ubiquity can cause a problem during major events or disasters, when cell phone networks become quickly jammed up with activity.
Now, a University of British Columbia researcher has devised a way to make certain that mobile calls don’t get dropped and texts make it to their destination. The new method uses television and radio channels to transmit information when cellular systems are stressed beyond capacity, according to a new report in the journal IEEE Transactions on Wireless Communications.
"If you have an event where there's a large crowd, for example a soccer match, an event such as a film festival or it can be an emergency case where the cellular coverage is (poor),” Mai Hassan, who developed the method, told The Canadian Press.
“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,” Hassan 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.”
To create her novel system, Hassan had to alter the shape of the wireless signal so that it could be sent on channels set aside for radio or television frequencies. She also had to shift the course of the phone’s transmission away from the originally demarcated channel.
Hassan’s system takes advantage of the so-called smart antennas found in cell phones. Unlike traditional antennas, smart antennas send signals in a particular direction and can direct that transmission in any particular path. By altering the direction of the cellular transmissions, Hassan could send calls and texts to a handset without affecting radio and televisions signals.
Much like Thomas Edison, the University of British Columbia engineer developed her novel system after several flawed iterations. One of her first attempts used mobile phones equipped with several smart antennas. The signals from these multiple antennas often overlapped and interfered with one another. Occasionally those overlaps would negate one another and block a transmission, referred to as destructive interference. However, the interference occasionally boosts the signal, also called constructive interference.
Hassan was able to use constructive interference to get the cellular transmission to its receiver and destructive interference to cancel a signal in areas where radio or television signals were being sent.
Next, Hassan decided to explore a more cost effective system. She realized she could exploit the mass of mobile phones using a particular network. With each device having only one smart antenna, Hassan was able to coordinate the same constructive/destructive interference pattern she had with multiple antennas on the same device. While the phone users may be located in different geographical locations, Hassan was able to surmount any non-synchronistic transmissions, essentially turning the problem of crowded phone use into an opportunity.
While a phone using this system isn’t currently available, Hassan said it could be an inexpensive addition to any device since much of the hardware is already in place. She added that the technology is still very much in the research phase.
“We would need researchers from other disciplines, for example electronic engineers and other disciplines so we aren't at that phase yet,” she said.