US researchers have built radio devices that can simultaneously transmit and receive using the same frequency and therefore potentially double the available telecommunication spectrum.
The nanoscale “full-duplex radio integrated circuits” (ICs) technology overcomes the limits of previous transmitters and receivers that either work at different times or at different frequencies, according to its inventors at Columbia University in New York.
This could help free up space on the radio spectrum ready for the next generation of faster communication standards such as 5G mobile signals and the greater use of internet-enabled devices and objects, the so-called Internet of Things.
“This is a game-changer,” said research leader associate professor Harish Krishnaswamy. “By leveraging our new technology, networks can effectively double the frequency spectrum resources available for devices like smartphones and tablets.”
Krishnaswamy added in a statement that other research groups and startup companies have demonstrated the theoretical feasibility of simultaneous transmission and reception at the same frequency, but no one has yet been able to build tiny nanoscale ICs with this capability.
“Our work is the first to demonstrate an IC that can receive and transmit simultaneously,” he said. “Doing this in an IC is critical if we are to have widespread impact and bring this functionality to handheld devices such as cellular handsets, mobile devices such as tablets for WiFi, and in cellular and WiFi base stations to support full duplex communications.”
The biggest challenge the team faced was canceling the echo of the signal sent by the transmitter, which can effectively overpower incoming signals to the receiver.
The researchers now plan to test a number of full-duplex nodes to understand what the gains are at the network level.
The work was funded by the government defence agency DARPA through its Radio Frequency-Field Programmable Gate Arrays (RF-FPGA) programme.