Four Research Projects Working Towards Doubling Wireless Bandwidth

If you’re as sick of slow internet as I am, here’s some good news. There are four huge research projects going on that are seeking to double wireless bandwidth. Not only is this great for all of us who like to stream video,  but it is entirely necessary as we shift into the Internet of Things (IoT). With all of these devices hooked up to the wireless network all the time, it’s bound to get a little crowded. These new innovations are hoping to go beyond 802.11ac and help us achieve something closer to the speed of light by allowing transmit and receive channels to occupy the same spectrum space.

Keep an eye out for these four research projects that could double wireless bandwidth:

Non-Magnetic Circulator– The key to, Andrea Alù’s, an associate professor of electrical and computer engineering at the University of Texas at Austin, is a magnetic-less radio wave circulator. Although this magnetic based circulators are no strangers to the wireless world but the fact that they are too big, too heavy and too expensive due to the magnets were the biggest drawbacks of every implementing that technology in any kind of mass produced setting.

Released from a dependency on magnetic effects, the circulator developed by Alù and his research team offers a much smaller footprint and uses less expensive materials than current circulators. The new device’s cost and size efficiencies promise to make the circulator a standard technology in phones and other mobile devices, enabling faster and more spectrum efficient service, Alù says.

The team’s prototype circulator has a two-centimeter diameter. The device could eventually be scaled down to just a few microns, Alù says. The prototype is based on materials widely used in integrated circuits, including small amounts of gold, copper and silicon, which makes it easy to integrate the circulator into circuit boards.

New Transceiver Architecture- Over at the University of Bristol, a research group lead by doctoral student Leo Laughlin has created a new full duplex transceiver architecture that will cancel out interference from the end-user’s own device and allows for transmission and reception on the same channel simultaneously. This means that only one channel will be required for two-way communication.

Laughlin developed the transceiver architecture based on research begun by supervisor Mark Beach, a Bristol professor of radio systems engineering. The system’s key enabling technologies are analog and digital cancellation technologies. “The transceiver combines electrical balance isolation and active radio frequency cancellation to suppress interference by a factor of over 100 million,” Laughlin says. A current prototype uses low-cost, small form factor technologies designed for use in smartphones and tablets.

Division-free duplexing can theoretically provide a two-fold increase in spectrum efficiency, yet a real world system will likely offer something less than a two-fold improvement. “However, any increase in spectral efficiency would translate into a range of benefits, including increased data rates and reduced cost and power consumption in the network infrastructure,” Laughlin says.

A Chip-Oriented Approach– Back across the Atlantic at Columbia University led by Harish Krishnaswamy, researchers are working on a chip-oriented approach that will enable reliable and efficient full duplex wireless communication. The group has developed full-duplex radio integrated circuits that will, in the same vein as new transceiver architecture, allow simultaneous transmission and reception on the same frequency.

“Having a transmitter and receiver use the same frequency offers the potential to immediately double network data capacity,” Krishnaswamy says. “Our work is the first to demonstrate an IC that can receive and transmit simultaneously,” he says. CMOS is the dominant technology used for radio ICs inside phones and other radio-equipped mobile devices.

The biggest challenge the team faced during its research was canceling transmitter echo, a phenomenon that makes usable full duplex impossible. “What you really need to do is to cancel-out that echo to the point where it’s eliminated almost perfectly and the residual echo is extremely small—smaller than the received signal, the desired signal—that you’re trying to receive from the distant cell tower,” he says.

Since the echo is over a billion times more powerful than the received signal, echo cancellation circuits must operate highly precisely. “We need echo cancellation circuits that are something like one-part-per-billion-level accurate,” Krishnaswamy explains.

Extra Antenna- A Rice University team lead by Ashutosh Sabharwal has the relatively simpler idea of adding a small antenna to all mobile devices going further.

The approach relies on MIMO (Multiple-Input Multiple-Output), a wireless technology that uses several transmitter and receiver antennas for increasing a radio’s data transfer capacity. “We utilized a multiple antenna approach for our full-duplex system because it requires only a minimal amount of new hardware, both on mobile devices and the network hardware,” says team leader Ashutosh Sabharwal, a Rice professor of electrical and computer engineering. “So far, we’ve attracted the interest of nearly every wireless company in the world.”

Sabharwal says that the approach is designed to address the needs of both device users and manufacturers. “On the device side, we’ve proven that we can supply full duplex easily and cost effectively as an additional mode on existing hardware,” he says. “As mobile devices become smaller, inside space becomes increasingly scarce and valuable, so manufacturers really appreciate an approach that doesn’t require them to add new hardware simply to provide a full duplex capability.”

The Rice technology uses a pair of signals that are designed to cancel each other out at the receiving antenna. “The canceling effect is entirely local, so the other node can still hear what we’re sending,” Sabharwal says. He notes that although the cancellation concept is not particularly new, and is relatively simple in theory, no one else had determined a way to implement the idea in a way without requiring complex and expensive new radio hardware.

These projects, most embracing the full-duplex technology of sending and receiving signals simultaneously, cutting down the time it takes to communicate through wireless technology, are a ways away. While we may have to wait with bated breath on hope that highly accelerated wireless speeds are somewhere in our foreseeable future, we’ll just have to make due with 802.11ac for now.