E Band Gets Satellite Interest, Faces Looming Clash

While the E band isn't widely used by commercial satellite communications today, satcom operators are urging the FCC to ensure future access and many see it the spectrum becoming contested space between satellite and wireless interests. Dennis Roberson of Roberson and Associates said there "inevitably" will be a fight over satellite vs. terrestrial use as there's always demand for exclusivity.

Evolving technology such as multiple-input multiple-output antennas allowing for steering capabilities has opened up the band to use that a couple decades ago was considered unfeasible, and demand for it will grow as the tech continues to evolve, Roberson said. He said satellite sharing can be done "easily" at least with point-to-point terrestrial applications like backhaul, since communications with non-geostationary orbit satellites is going to be largely straight-up vertical while terrestrial communizations would be horizontal. With other applications, such as control of unjammed aerial vehicles, "all bets are off" in terms of sharing, he said.

The E band "is still largely virgin ground," with little satellite activity except perhaps for military applications, emailed satcom expert Giovanni Corazza, professor at the University of Bologna. Generally, the higher the frequency, the easier coexistence is between satellite and terrestrial links in the same band because antennas become increasingly directive and the angular separation should be enough to avoid mutual interference, he said.

Broadband satellite interest in the E band wouldn't be new. Facebook's PointView Tech in 2019 received an experimental license from the FCC for a cubesat that would operate in what it called the "little-used" 71-76 GHz and 81-86 GHz bands and "test whether LEO satellites using E-band spectrum can be an efficient means for providing fixed and mobile broadband access service." OneWeb in 2020 withdrew a U.S. market access petition amendment that saw it asking to also include the 71-76 GHz and 81-86 GHz bands. Facebook and OneWeb didn't comment.

The E band is not seeing heavy scrutiny in other countries currently, a satellite company regulatory lawyer said. With no World Radiocommunication Conference agenda item in 2019 or 2023 on the topic, the spectrum doesn't seem to be a priority for new, we're told. An ETSI white paper last year said the E-band was growing in popularity for mobile backhaul and some European nations are using the 71-74 GHz and 81-84 GHz bands solely for military applications, while others allow shared use between civil and military.

While higher frequencies are more susceptible to atmospheric and rain fade, they are viable for cross-links and certain systems, emailed satcom expert Whitney Lohmeyer, Olin College of Engineering assistant professor. She said currently most fixed satellite systems like OneWeb, SpaceX and Amazon's Kuiper operate in the Ku and Ka bands but often have filings for higher frequencies, including the E band. Coordination in the higher bands shouldn't be any more challenging than in the Ka band, which satellite systems share with terrestrial systems, she said.

The band's big challenge "is that it's a fair-weather friend," with propagation characteristics that see it easily disrupted by clouds, rain or even transmitting to a receiver from an oblique angle close to the horizon, quipped Roberson. But the sizable amounts of spectrum in the band could mean especially wide channel sizes, and more bandwidth means more capacity and thus higher rates of data transfer, he said.

Some satellite interests are telling the FCC coexistence with terrestrial services such as terrestrial backhaul is viable (see 2109230006). A satellite industry executive told us the E band is likely to end up contested, given that both satellite and wireless industries need more spectrum. He said sharing with terrestrial point-to-point is relatively easy except when mobility enters the picture, making it more challenging to identify and avoid sources of interference. He said the E band might not end up being employed for mobility purposes given the power requirements of high-frequency spectrum.