Low-heat radios could replace cable links in data centers

A more efficient design that combines antenna and electronics could replace traditional radio links, improving energy and spectral efficiency, Georgia Tech researchers say.

Low-heat radios could replace cable links in data centers
Allison Carter, Georgia Institute of Technology

Future 5G-based wireless networking equipment and data center equipment will combine antennas and the corresponding radio guts into one microprocessor unit, researchers from the Georgia Institute of Technology say.

Integrating all of the wireless elements that one needs in a radio will reduce waste heat and allow better modulation, according to the group, which has been working on a one-chip, multiple transmitter and receiver package design. Longer transmission times and better data rates will result, they say.

“Within the same channel bandwidth, the proposed transmitter can transmit six- to ten-times higher data rate,” says Hua Wang, an assistant professor in Georgia Tech's School of Electrical and Computer Engineering, in a news article on the university’s website about the idea.

The design they’ve been working on would be particularly suitable for the millimeter bands that will be used in later 5G, they say. That’s because large numbers of elements could be combined — multiple antennas and radios will be good for propagating the tiny frequencies. Putting them all together with the minimum of connections would introduce efficiencies needed.

The new co-design “significantly enhances the efficiency of the entire transmitter,” Wang says. “Hundreds or even thousands of elements [could] work together as a whole system” — meaning compact systems could be created.

And indeed one could simply add more modular chips in a tile pattern to create bigger arrays for MIMO (multiple-in-multiple-out) antennas or, alternatively, place more transmitters and receivers on the same chip” to get to MIMO, the news article suggests. MIMO is a technique used in radio antenna design that exploits multipath — it roughly multiplies the signal paths using multiple antennas.

How data centers could benefit from combined antenna electronics radio

Infrastructure in data centers could benefit from combined antenna electronics radio, too, Wang says. Link cables could be replaced in large halls using the scheme — better data rates coupled with lower cooling requirements, compared with other radio equipment, will make the combined antenna and electronics chips attractive for thermal management reasons, he says.

Interestingly, the researchers claim their design is able to sustain energy efficiency when the radio is working at both peak output power and at average power. That’s not how normal transmitters function, the school explains, as conventional transmitters are usually efficient at peak power only.

The group optimizes output voltages and currents of the power transistors to obtain some gains. Elaborate modulation protocols are also used to obtain a higher data rate, the researchers say. And then, of course, the aforementioned connections between parts, including other miscellaneous electronics, that degrade efficiency usually are junked.

“Integrating the antenna gives us more degrees of freedom to explore design innovation, something that could not be done before,” Wang says.

Interestingly, it’s the merging of two completely separate engineering disciplines that’s taking place in the chip design, the school points out — antennas and radio circuit boards are usually designed and researched distinctly from each other.

“We are merging the technologies of electronics and antennas, bringing these two disciplines together to break through limits,” says Sensen Li, a Georgia Tech graduate research assistant, in the article.

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