New full-duplex technology doubles wireless capacity

Rice University engineers have developed technology that allows for wireless devices like cell phones and tablet PCs to both "talk" and "listen" to wireless cell towers on the same frequency, paving the way for 5G networks.

Rice University engineering researchers have demonstrated a new device that could allow wireless phone companies to double throughput on their networks without adding a single cell tower, and they've shown that it could work on a real network.

Current wireless technologies rely on two frequencies to send and to listen. Full-duplex allows communication in both directions simultaneously, such as in land-line telephone networks. Long thought impossible for wireless networks, Rice's team overcame the full-duplex hurdle by employing an extra antenna and some computing tricks.

"Our solution requires minimal new hardware, both for mobile devices and for networks, which is why we've attracted the attention of just about every wireless company in the world," said Ashutosh Sabharwal, professor of electrical and computer engineering at Rice. "The bigger change will be developing new wireless standards for full-duplex. I expect people may start seeing this when carriers upgrade to 4.5G or 5G networks in just a few years."

As I've reported last February, Stanford researchers have also developed a system that allows wireless signals to be sent and received simultaneously on a single channel, but Rice has taken it a step further with a demo (see paper) that produced a signal quality about 10 times better than any previously published result.

Jade Boyd, associate director and science editor at Rice, told me over email: "We’re also the first to demo asynchronous full-duplex. Our people have published the first experimental work on full-duplex with directional antennas, and they’ve offered a theoretical analysis to explain their experimental results."

While Rice and Stanford teams are attacking the same problem and using the same research platform, WARP (Wireless Open Access Research Platform--an open-source development platform developed by Dr. Sabharwal’s group a few years ago), they’re using different technologies. For instance, Rice’s technology would allow wireless device makers to add full duplex as an additional mode on existing hardware by repurposing most of the components that are already used in current systems. "I believe that’s also a first — and a key one for device makers,"  said Boyd.

"Device makers love this because real estate inside mobile devices is at a premium, and it means they don’t have to add new hardware that only supports full-duplex,” said Sabharwal.

In the video below, you can learn more about the full-duplex test device and the technology behind the breakthrough: