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Digital-Analog ‘Beyond 5G’ Transceiver Prototype Boosts RF into the 100GHz Range

July 30, 2019 by Scott McMahan

A group of electrical engineers from the University of California Irvine (UCI) developed a wireless transceiver that they claim can process data using less energy at speeds beyond 5G. They created a new wireless transceiver that boosts radio frequencies into 100-gigahertz region, which is quadruple the speed of the upcoming 5G (fifth-generation) wireless communications standard.

Its creators from UCI's Nanoscale Communication Integrated Circuits Labs labeled it an "end-to-end transmitter-receiver". (See image above--(from left) Payam Heydari, director of UCI's Nanoscale Communication Integrated Circuits Labs and professor of electrical engineering & computer science; and lab members Hossein Mohammadnezhad, who earned a Ph.D. in electrical engineering & computer science this year, and Huan Wang, a doctoral student in the same department -- photo courtesy of Steve Zylius / UCI).

The 4.4mm2 silicon chip with its unique digital-analog architecture can of process digital signals significantly faster and more energy-efficiently. The team's development is outlined in a paper recently published in the IEEE Journal of Solid-State Circuits.

"We call our chip 'beyond 5G' because the combined speed and data rate that we can achieve is two orders of magnitude higher than the capability of the new wireless standard," said senior author Payam Heydari, NCIC Labs director and UCI professor of electrical engineering & computer science. "In addition, operating in a higher frequency means that you and I and everyone else can be given a bigger chunk of the bandwidth offered by carriers."

The "end-to-end transmitter-receiver" chip boasts a unique architecture combining digital and analog components on a single platform, resulting in ultra-fast data processing and reduced energy consumption. -- photo courtesy of Steve Zylius / UCI

He said that communications circuit engineers and academic researchers have long wanted to know if wireless systems can achieve the high performance and speeds of fiber-optic networks. "If such a possibility could come to fruition, it would transform the telecommunications industry, because wireless infrastructure brings about many advantages over wired systems," Heydari said.

His group's solution is in the form of a new kind of transceiver that leaps over the 5G wireless standard --designated to operate in the range of 28GHz to 38GHz - into the 6G standard, which is expected to operate at 100GHz and higher.

"The Federal Communications Commission recently opened up new frequency bands above 100 gigahertz," said lead author and postgraduate researcher Hossein Mohammadnezhad, a UCI grad student at the time of the work who this year earned a Ph.D. in electrical engineering & computer science. "Our new transceiver is the first to provide end-to-end capabilities in this part of the spectrum."

The "end-to-end transmitter-receiver" chip's unique architecture combines digital and analog components on a single platform. This combination results in ultra-fast data processing and reduced energy consumption.

Transmitters and receivers that handle such high-frequency data communications are foreseen to be critical in bringing about a new wireless era in which IoT, autonomous vehicles, and vastly expanded broadband for streaming of high-definition video content dominate.

While this digital concept has driven technology developers for decades, obstacles have started appearing. According to Heydari, using modulation and demodulation to change the frequencies of signals in transceivers has traditionally been accomplished with digital processing.

However, in recent years, IC engineers have begun to see the physical limitations of this strategy.

"Moore's law says we should be able to increase the speed of transistors - such as those you would find in transmitters and receivers - by decreasing their size, but that's not the case anymore," he said. "You cannot break electrons in two, so we have approached the levels that are governed by the physics of semiconductor devices."

To overcome this issue, NCIC Labs researchers utilized a chip architecture that considerably relaxes digital processing demands by modulating the digital bits in the analog and RF domains.

Heydari said that in addition to enabling signal transmission in the range of 100 gigahertz, the transceiver's unique arrangement allows it to consume significantly less energy than current systems at a reduced overall cost.

Heydari says that the transceiver's technology could pave the way for widespread adoption in the consumer electronics sector.

Co-author Huan Wang, an NCIC Labs member, and a UCI doctoral student in electrical engineering & computer science said that the technology combined with phased-array systems, which use multiple antennas to direct beams, aid several disruptive wireless applications.

"Our innovation eliminates the need for miles of fiber-optic cables in data centers, so data farm operators can do ultra-fast wireless transfer and save considerable money on hardware, cooling, and power," he said.

TowerJazz and STMicroelectronics provided semiconductor fabrication to support this research project.