A small startup company is testing a new technology that may enable mobile devices to simultaneously transmit and receive data on a single frequency.
Founded by a group of Stanford University researchers, who in 2011 developed the first wireless radios capable of sending and receiving signals at the same time, California-based Kumu Networks Inc. believes its new technology could help alleviate spectrum congestion by effectively doubling the capacity of both cellular and Wi-Fi communications.
“At this point, many people say we have exhausted our tools to improve spectrum efficiency,” Sachin Katti, Kumu’s chief executive and co-founder, told The Wall Street Journal. “Operators, when they look at [our technology], see that there is one big tool left.”
The technology directly tackles the concept of self-interference, in which a radio’s own transmissions effectively drown out incoming signals from other sources. The technique employed is similar to that used by noise-cancelling headphones.
“When a radio is transmitting, its own transmission is millions, billions of times stronger than anything else it might hear [from another radio],” Philip Levis, assistant professor of computer science and of electrical engineering and one of the primary researchers on the 2011 project, explained. “It’s like trying to hear a whisper [from someone else] while you yourself are shouting.”
To avoid the problem, communication systems often allocate separate frequency bands for sending and transmitting information or take turns transmitting on the same band. Kumu’s technology instead uses a combination of chips and proprietary algorithms to analyze the signals emanating from a device’s own transmitter and generate counter-signals to cancel out the signals being transmitted. This allows the device’s receiver to receive signals from other sources, Joel Brand, Kumu’s vice president of product management, explained in an interview with The Wall Street Journal.
While some proposed applications for the new technology require industry groups that set technical standards and mobile device makers to recognize and incorporate the technology—a process that could take years, says Katti—the technology could be implemented sooner in radios on cellular towers that communicate with mobile phones to provide a more immediate benefit.
Brand believes the technology could also be used in crowded locations where interference prevents smartphones from getting a reliable signal, such as a sports stadium or convention center, or in defense-related applications that require troops to jam radio transmissions.
“If they use our technology, they could jam and still hear their own transmissions,” he said.
Kumu plans to test prototypes of its devices over the next six months with undisclosed partners, and hopes to put equipment on the market next year that could be used by carriers to ease certain types of network congestion problems.