BT: 'Quantum radios' could boost 5G network range

Tech exploits electromagnetically induced transparency to form highly sensitive electric field detector


Brit telecoms giant BT is undertaking a trial of new antenna technology that may boost the range of 5G networks and reduce mobile network energy consumption.

The receiver technology works by exploiting a quantum effect called "electromagnetically induced transparency" to form a highly sensitive electric field detector. According to BT, this could theoretically make it over 100 times more sensitive than traditional receivers, allowing it to detect weaker signals and thus extend the range of a mobile network deployment.

Regular readers will no doubt have become twitchy at the mention of the word "quantum" so we asked BT if it could supply us with a simple explanation of how the new antenna technology works. It told us:

A conventional dipole antenna is a macroscopic solid conductor and subject to thermal noise as the billions of atoms jostle each other at room temperature. In a diffuse gas, the atoms interact much less, so thermal noise can be reduced and the signal-to-noise ratio is [increased] even for weak signals, especially in a narrow frequency band.

BT also directs those with an interest in this technology to an article its researchers published in the Journal of Lightwave Technology. This mentions the use of Rydberg RF sensors to exploit the electromagnetically induced transparency effect in an atomic vapor.

This relies on Rydberg atoms that are highly excited, which means they have one or more electrons that are highly energetic and thus farther out from the nucleus of the atom. Rydberg atoms have a number of peculiar properties including an exaggerated response to electric and magnetic fields, or so we understand, and this is utilized in a Rydberg RF sensor.

This technology is not actually new, and the US National Institute of Standards and Technology (NIST) is recognized as a leader in developing and exploring Rydberg sensors for a variety of applications.

What is new in BT's trial is that the technology has been used for the first time to receive a digitally encoded transmission sent over a 3.6GHz carrier frequency, demonstrating that it is possible for Rydberg RF sensors to be deployed as part of a 5G network.

BT's ongoing work is now aimed at simplifying these very complex devices so that they can be deployed in the field, utilizing an economic laser source in the receiver.

In the abstract for its research article, the BT researchers explain: "We present a simple analytic model for the operation of a sensitive Rydberg RF receiver to predict the optical modulation in response to an RF signal... by detuning the coupling frequency to compensate for the RF detuning we demonstrate that the useful RF bandwidth of the receiver can be significantly extended... This convenient analytic approach will simplify the design and operation of Rydberg RF receivers as sensitive components in future 5G mobile communications, particularly for the power-limited uplink from mobile device to base-station."

The researchers at BT Labs in Martlesham are working to miniaturize the equipment and find the optimum RF modulation and signal processing for potential use in future generations of radio networks.

This is not likely to happen overnight, as BT Senior Manager for Network Physics Fraser Burton – one of the researchers – told us.

"A commercial product is at least three to five years out, so network deployment within the decade is possible," Burton said.

While the technology is still in the very early stages, it has the potential to provide greater sensitivity than conventional radio antennas, according to BT, with tuneable operation from very low frequencies, detection of analogue and digital modulation, and low energy consumption through reduced need for electronics.

BT said it has also been granted a number of patents relating to its implementation of the atomic RF receiver technology. ®

Broader topics


Other stories you might like

  • Alcatel-Lucent Enterprise adds Wi-Fi 6E to 'premium' access points
    Company claims standard will improve performance in dense environments

    Alcatel-Lucent Enterprise is the latest networking outfit to add Wi-Fi 6E capability to its hardware, opening up access to the less congested 6GHz spectrum for business users.

    The France-based company just revealed the OmniAccess Stellar 14xx series of wireless access points, which are set for availability from this September. Alcatel-Lucent Enterprise said its first Wi-Fi 6E device will be a high-end "premium" Access Point and will be followed by a mid-range product by the end of the year.

    Wi-Fi 6E is compatible with the Wi-Fi 6 standard, but adds the ability to use channels in the 6GHz portion of the spectrum, a feature that will be built into the upcoming Wi-Fi 7 standard from the start. This enables users to reduce network contention, or so the argument goes, as the 6GHz portion of the spectrum is less congested with other traffic than the existing 2.4GHz and 5GHz frequencies used for Wi-Fi access.

    Continue reading
  • Software-defined silicon is coming for telecom kit later this year
    Startup EdgeQ believes pay-for-what-you-use model will make 5G transition more cost-effective

    Interview While the IT industry waits to see if and when Intel will introduce software-defined silicon in Xeon CPUs, one startup is moving ahead with plans to bring a pay-for-what-you-use pricing model to the telecom market with its "base station-on-a-chip" later this year.

    Silicon Valley-based EdgeQ, which is led by former Qualcomm and Intel executives, announced last week that it has begun sampling an EdgeQ-based 5G small cell and OpenRAN PCIe accelerator card for base stations with telecom operators and equipment makers.

    Things are apparently moving smoothly enough for the startup that Adil Kidwai, EdgeQ's head of product management, told The Register that its RISC-V-based chip will appear in mass-manufactured products like small cells and base station accelerator cards "by the end of this year."  

    Continue reading
  • 5G C-band rollout at US airports slowed over radio altimeter safety fears
    Well, they did say from July, now they really mean from July 2023

    America's aviation watchdog has said the rollout of 5G C-band coverage near US airports won't fully start until next year, delaying some travelers' access to better cellular broadband at crowded terminals.

    Acting FAA Administrator Billy Nolen said in a statement this month that its discussions with wireless carriers "have identified a path that will continue to enable aviation and 5G C-band wireless to safely co-exist."

    5G C-band operates between 3.7-3.98GHz, near the 4.2-4.4GHz band used by radio altimeters that are jolly useful for landing planes in limited visibility. There is or was a fear that these cellular signals, such as from cell towers close to airports, could bleed into the frequencies used by aircraft and cause radio altimeters to display an incorrect reading. C-band technology, which promises faster mobile broadband, was supposed to roll out nationwide on Verizon, AT&T and T-Mobile US's networks, but some deployments have been paused near airports due to these concerns. 

    Continue reading

Biting the hand that feeds IT © 1998–2022