The Defense Innovation Board, shown here at a July 10 quarterly
meeting at the Defense Innovation Unit Experimental, in Mountain View,
Calif., predicts the move to 5G could also increase the likelihood of
offensive cyber operations as defense gets harder. Photo: Sgt. Ray Aquino/Air National Guard
Most mobile communication today takes place at spectrum bands below 3 GHz, according to mobile technology chipmaker Qualcomm. But 5G wireless networks in the US will operate in the millimeter-wave band, between 30 GHz and 300 GHz, a part of the spectrum set aside for this use in this country, but not worldwide.
This issue is at the center of today’s struggle between the US and China over 5G technology and the role played by Chinese telecommunications technology provider Huawei.
In the millimeter-wave band, signals do not propagate well over long distances, which poses a problem: While acceptable for dense urban and crowded indoor areas, where positioning additional antennae is relatively easy, the higher frequencies are ill-suited to open areas where frequent placement of antennae is impractical. There, bands below six GHz (“sub-6”) are more effective.
The trouble is, that spectrum isn’t available in the US for general commercial use—it’s reserved for the Defense Department. DOD must now determine if and how to share it with commercial users.
Some suggest the military should focus on higher bands. “Access to the 5G millimeter-wave bandwidth will be critical to operations in all warfighting domains, in particular, space C2,” wrote Air University scholars in a 2018 report. “[Electromagnetic spectrum] experts assess that 5G market share could be ‘locked up’ by US competitors in under three years with no second chances to enter the race.”
The Defense Innovation Board, however, came to a different conclusion. It called DOD’s focus on millimeter-wave spectrum “fundamentally flawed” and “impractical.”
“The United States may choose to continue down the path of mmWave, but the rest of the world is focused on building out sub-6 infrastructure, with China in the lead,” the DIB wrote. “Although mmWave components are typically more compact than sub-6 components, mmWave requires many more base stations positioned within close proximity of one another to maintain connection (and even then, there is still the risk that interference such as objects moving in front of the base station or weather will interrupt the connection).”
The board pointed to a 2010 broadband plan that could offer a blueprint for sharing the sub-6 part of the spectrum with non-DOD users by giving DOD priority access while allowing commercial users access when that spectrum is not in military use.
The DIB raised concerns that crowding sub-6 could reduce system performance and create vulnerabilities, and that tools built for certain parts of the spectrum would not be compatible with tools built for the others.
“In the current 5G competition, neither DOD nor the United States writ large is in a position to dictate the content and integration of the 5G supply chain—our focus on building a mmWave 5G ecosystem leaves us out of the global supply chain for the sub-6 5G ecosystem,” the DIB wrote. “This mismatch will create serious security risks for DOD going forward if the rest of the world accepts Chinese products as the cheaper and superior option for 5G.”
The DIB issued three public recommendations and one classified suggestion to DOD for moving forward on 5G.
“5G capability requires larger bands of spectrum, and without that additional bandwidth, the United States will not gain true 5G capability beyond the limited range that mmWave can provide,” according to the DIB. “In the next year, DOD is in the position to enable or inhibit 5G adoption in the United States based on its use of sub-6 GHz spectrum.”
Notably, the DIB predicts the move to 5G could also increase the likelihood of offensive cyber operations as defense gets harder.
Ready or not, 5G is coming—and the Pentagon’s innovation advisers aren’t entirely optimistic.
“Gaining a competitive edge over China [in sub-6] would require action at a rate and magnitude previously unseen within DOD,” the DIB warned. “For this reason, it is probable that most of the world outside of the United States will adopt a sub-6 5G solution, forcing DOD to operate on a ‘post-Western’ wireless ecosystem.”
Daily Report: Read the day's top news on the US Air Force, airpower, and national security issues.
Tweets by @AirForceMag