Jan 7, 2022 - Technology

Overcoming 5G's tree problem

Illustration of a tree trunk with a Wifi symbol in place of leaves

Illustration: Annelise Capossela/Axios

It's been long known that trees can slow down some 5G signals. A recent federal study aims to figure out just how much, in order to create more accurate signal strength prediction models.

Why it matters: 5G has the potential to supercharge wireless networks, but its rollout has revealed a range of complex challenges.

What they found: Researchers at the National Institute of Standards and Technology measured the strength of signals that rely on the high-frequency millimeter wave spectrum through different types of trees during different seasons of the year.

  • Researchers have known that obstacles like foliage or even rain could reduce millimeter wave signal strength, but the NIST team wanted to more precisely measure the impact trees have.
  • The researchers conducted measurements on seven types of trees at their campus in Gaithersburg, Maryland.
  • As expected, the leafier the tree, the more strength the signal lost, Nada Golmie, chief of NIST’s wireless networks division in the Communications Technology Laboratory, told Axios.
  • The research, which is part of an ongoing project, aims to provide more precise measurements of that signal loss, which Golmie says NIST is sharing to help make modeling more accurate.

What they're saying: "By providing measurements, and methods to measure, we're enabling others to more accurately, precisely assess the loss so that it can be overcome," Golmie said. "We believe it can be overcome."

The big picture: Verizon already uses millimeter wave spectrum for some of its 5G services, but both it and AT&T plan to use airwaves at a lower frequency known as the C-band to expand 5G service.

  • Spectrum at that lower frequency can better penetrate obstacles, but the C-band comes with its own set of controversies amid concerns from the aviation industry about potential interference. (T-Mobile isn’t using C-band for its 5G services and has avoided the drama.)

What's next: With more services crowding airwaves, Golmie says using millimeter wave spectrum — and overcoming its limitations — will be necessary.

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