A team of Columbia Engineering researchers has invented a breakthrough technology that could double radio frequency data capacity. Wireless radios normally either work at different times or on different frequencies, but the new technology, called full-duplex radio integrated circuits (ICs), allows for simultaneous transmission and reception. The Columbia team’s invention is the first to demonstrate miniaturization of a full-duplex transceiver onto an IC. They have shown that the technology can be applied in nanoscale CMOS (microchip) small enough to be practical in commercial applications such as smart phones or tablets. The work was funded by the DARPA RF-FPGA program and presented at the International Solid-State Circuits Conference (ISSCC) in San Francisco on February 25.
The biggest challenge the researchers faced was eliminating transmitter echo, which they described as being as wasteful as a person yelling in your ear while you are trying to listen to someone else whisper from far away. Lead author Jin Zhou, said, “If everyone could do this, everyone could talk and listen at the same time, and conversations would take half the amount of time and resources as they take right now. Transmitter echo or ‘self-interference’ cancellation has been a fundamental challenge, especially when performed in a tiny nanoscale IC, and we have found a way to solve that challenge.”
Many researchers are working to find ways for to increase spectrum resources in order to keep up with high demand for wireless data. Standards such as 4G/LTE are already running out of space, and although there are exciting 5G developments in progress, they aren’t expected to be commercially viable until 2020. In the meantime, the new full-duplex radio ICs can help make the most efficient use of available networks. The researchers are now working with network theory experts at Columbia to test full-duplex nodes to understand how the performance gains will translate on a network level.