However, if the United States and DoD do not pivot to sub-6, DoD will face further challenges with acquisition and practical deployment of 5G. 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). This quickly becomes logistically impractical if a person or platform has to carry multiple antennae, particularly at the fighting edge. Additionally, the DoD acquisition system is slow-moving and might take years to deploy the necessary systems for a mmWave network, at which point most of those systems might already be obsolete. Both DoD and the FCC are currently prioritizing mmWave over sub-6 mid-band spectrum with a particular focus on the 28 and 37 GHz bands, but this is a fundamentally flawed focus due to the impracticality of mmWave deployment. DoD must prepare to operate in a sub-6 5G ecosystem, which will require a shift in strategy and a consideration of where DoD is willing to share bandwidth in the sub-6 realm.
This shift may come with some inherent benefits. The anonymity that comes from utilizing the same infrastructure as any other company or country provides an industry-standard form of security all its own. Integration of government and civil use may provide a layer of security by allowing military traffic to “hide in plain sight” as traffic becomes more difficult to see and isolate. Similarly, adversaries might be deterred from jamming this spectrum because they might be operating on the same bands. Government will maintain primary spectrum access while also benefiting from technology advancements from the commercial sector that result from operations in the sub-6 range, which will help the government to close the gap between the commercial sector and current state of military communications. This also creates an opportunity for cyber and communications personnel to learn how to make spectrum more resilient by working regularly with shared spectrum and managing it both domestically and abroad.
A Path Forward for Sub-6 Spectrum Sharing
The idea of spectrum sharing is not new. In 2010, the FCC identified the spectrum band from 3550-3700 MHz, known as Citizens Broadband Radio Service (CBRS), as a potential spectrum-sharing opportunity. CBRS utilizes LTE networks to provide wireless voice, text, and data services, and this spectrum was freed as a result of the FCC’s 2010 National Broadband Plan to provide more spectrum for new mobile users.[1] In 2015, the FCC formally authorized the 3.5 GHz band for shared wireless access in an area that was previously utilized by the U.S. Navy and DoD. CBRS will enhance the “last mile” of fiber access to deliver fixed wireless service and also offer point-to-multipoint capabilities. CBRS spectrum can be unlicensed by the user, or they may purchase temporary licenses for periods of use, and it allows services to be deployed in a more rapid and efficient manner. DoD remains the incumbent user of the band, so other users will be limited by the Spectrum Access System (SAS), which ensures that there is deconfliction
- ↑ “National Broadband Plan,” FCC, March 17, 2010, https://www.fcc.gov/general/national-broadband-plan.
