When Cell Towers and Satellites Share the Sky: A Smarter Antenna Fix
June 8, 2026
When Cell Towers and Satellites Share the Sky: A Smarter Antenna Fix
A research paper submitted to the IEEE Global Communications Conference (GLOBECOM) 2026
As demand for wireless data keeps climbing, regulators and engineers are eyeing a stretch of radio spectrum called the upper mid-band (roughly 7–24 GHz) as prime real estate for next-generation 6G mobile networks. The catch? Parts of this spectrum are already spoken for. In particular, low-Earth-orbit (LEO) satellites—the kind that beam internet to remote areas—use nearby frequencies to receive signals from the ground. If future cell towers and existing satellites are going to share these airwaves, they need to do so without interfering with one another.
That coexistence problem is exactly what researchers Zhiyu Shen, J. Nicholas Laneman, and Bertrand Hochwald of the Department of Electrical Engineering at the University of Notre Dame tackle in their new paper. The work was supported by SpectrumX, the National Science Foundation’s Spectrum Innovation Center, and submitted to the IEEE Global Communications Conference 2026.
The Problem: A Few Towers Forced to Go Quiet
Here’s the core tension. A single LEO satellite passing overhead can “see” thousands of cell tower sectors at once. All of their signals add up at the satellite’s receiver, and that combined interference must stay below a strict protection limit so the satellite can still hear its own users on the ground.
Engineers already have a well-established tool for this: beamforming, a technique that shapes each tower’s transmission to serve its user while steering energy away from the satellite. When every tower respects its share of the interference budget, the satellite is protected. Problem solved—mostly.
The Notre Dame team discovered a subtle but stubborn exception. On the standardized antenna panels that the wireless industry (via 3GPP) is planning to use, a small fraction of cell sectors—about 0.17%—suffer severe service degradation when forced to protect the satellite. That sounds tiny, but these aren’t fleeting glitches: the researchers found that these bad situations can persist for tens of seconds (a median of 33 seconds, and in extreme cases over seven minutes) as the satellite moves across the sky. For the unlucky users connected to those towers, that means a real and lasting drop in service.
The Diagnosis: Blame the Antenna’s Ruler-Straight Geometry
Why does this happen? The team traced it to the physical layout of the antenna panel. These panels stack their antenna elements into evenly spaced groups called subarrays. That neat, repeating spacing creates a side effect known as grating lobes—unwanted “echo” directions where the antenna radiates energy whether you want it to or not.
In the troublesome cases, one of these grating lobes happens to point straight at the satellite at the same time the tower is trying to serve a user. The antenna physically cannot separate the two directions, so protecting the satellite means starving the user. The researchers showed mathematically and through simulation that the high-loss cases cluster precisely at the spacing-predicted grating-lobe directions—confirming the antenna’s regular geometry as the culprit.
The Innovation: Break the Pattern, Keep the Hardware
The elegant part of their solution is what it doesn’t require. Instead of adding antennas, increasing power, or redesigning the panel from scratch, the team simply repositions the subarray centers so they are no longer evenly spaced—an “aperiodic” layout. Crucially, the redesign keeps the same number of elements, the same control ports, the same overall antenna size, and the same manufacturing footprint. It’s a same-budget retrofit.
The results are striking. A mild, almost trivial adjustment cut the high-loss rate in half. A numerically optimized layout eliminated the high-loss events entirely across a 1,000-scenario validation test—while still satisfying the satellite protection requirement. In short, a clever rearrangement of existing parts solves a problem that brute-force software alone could not.
Why It Matters and What’s Next
This work reframes antenna geometry as a practical lever for spectrum sharing—useful for engineers designing 6G hardware and for policymakers weighing how terrestrial and satellite services can coexist. The authors point to promising next steps: relaxing the conservative “worst-case” interference assumption, deriving theoretical bounds on how often these bad cases occur, and extending the approach to multiple data streams and dual-polarized antennas.
By showing that thoughtful hardware design can quietly resolve a coexistence headache, the Notre Dame team offers a concrete path toward a future where our phones and our satellites can comfortably share the same slice of sky.
Authored by Zhiyu Shen, J. Nicholas Laneman, and Bertrand Hochwald, University of Notre Dame. Submitted to IEEE GLOBECOM 2026 (https://globecom2026.ieee-globecom.org). Supported by NSF SpectrumX (Award AST 21-32700).