Background

The National Spectrum Strategy calls for the U.S. government (USG) to complete—within 12 to 18 months—a “moonshot” effort, in collaboration with industry, that will advance research, create investment incentives, and set forth measurable goals for advancing the state of technology for spectrum access, with an emphasis on dynamic forms of spectrum sharing for all users. Developing an effective sharing capability will be critical to attaining technological leadership, including the ability to out-compete and out-innovate the People’s Republic of China (PRC). To maintain the U.S.’s first-mover advantage in dynamic spectrum sharing, more advanced capabilities are needed:

• As an example from a commercial perspective, while the Citizens Broadband Radio Service (CBRS) has demonstrated great promise and has received praise from some non-traditional wireless entrants, major wireless operators have argued that it has not created stable or significant enough spectrum access to facilitate high-stakes commercial deployments or significant contributions to 5G networks. These operators also argue that it has not incentivized changes by federal operators that would improve efficiency or performance for the overall ecosystem.
• From a national security perspective, the U.S. military and Intelligence Community (IC) needs continued assured spectrum access in an increasingly complex environment. To support this, the U.S. would benefit from the development of more agile, real-time, and responsive sharing capabilities.

Scope

The Advanced Dynamic Spectrum Sharing (DSS) demonstration, which should be conducted at Lower 3 GHz, specifically from 3.1 to 3.45 GHz, provides an opportunity to demonstrate in the field and go beyond what CBRS enables today while building on the work done in the EMBRSS study. This demonstration should show how to simultaneously create spectrum access for commercial users while enabling DOD to continue to accomplish its mission in a complex spectrum environment. To be successful, DSS must involve a whole-of-government effort, undertaken in partnership with industry and civil society, with a clear commitment to testing and adopting spectrum sharing mechanisms that simultaneously promote economic growth and national security objectives. This demonstration will be co-led by the National Telecommunications and Information Administration (NTIA) and the Department of Defense (DOD), in consultation and coordination with the FCC and relevant agencies.¹ The demonstration must be completed between March and September 2025, with the goal of bringing this capability to market within the next 5 years.

The DSS demonstration should be conducted under fully operational conditions, from an industry and government perspective, sufficient to determine the feasibility of the intervention at an adequate scale to properly assess the effects of aggregation, the effectiveness of coexistence solutions at different distances, and interference conditions. This real-world demonstration shall include the detailed involvement of the military services and relevant defense agencies as well as collaboration with industry partners.

The EMBRSS Report concluded that “[s]haring of the 3100-3450 MHz band between Federal USG and commercial systems is not feasible unless certain regulatory, technological, and resourcing conditions are proven and implemented as part of a coordination framework.” The DSS demonstration builds on the EMBRSS effort by developing a mechanism to resolve the technological barriers identified by the EMBRSS Report, specifically in the 3.1 to 3.45 GHz band. At the same time, the development of this mechanism is intended to have potential application to other spectrum bands. Please note, however, that there will also be an effort to study other opportunities for private-sector access in the band under several different scenarios (relocation, repacking, sharing, and a combination of different approaches).

Objectives

The goal of the demonstration is to achieve as many of the following objectives as possible:

1. Develop a Mechanism that Evolves Beyond the Existing Automated Frequency Coordination Frameworks, Including the CBRS Framework.
   • DOD and NTIA identify and implement improvements in spectrum coordination that go beyond the capabilities of current spectrum sharing mechanisms, for initial application in the 3.1-3.45 GHz band.
2. Demonstrate that DSS can enable the U.S. to More Effectively Operate in Adversarial Environments.
   • Leverage this DSS exercise to demonstrate how the U.S. military and the IC can prevail in the increasingly congested and contested environment in which they currently operate and must be prepared to operate in the event of a future conflict.
3. Improve the Ability of Commercial Radio Access Networks to Share.
   • DOD and NTIA, in coordination with a multistakeholder consortium consisting of government, industry, civil society, and academia, will introduce, evaluate, and demonstrate technology to enable DOD systems to coexist with commercial networks and evaluate the effectiveness of the demonstrated technology with respect to defined metrics. This will include technologies to improve the spectrum sensing and coordination capabilities by potentially leveraging DOD’s private networks capabilities on military bases. This may involve the development of separate and integrated base station sensors to detect incumbent signals and avoid transmissions that would interfere with them.
   • This would enable the USG to resolve federal use within “signal-on-signal” environments.
   • It would also enable the USG to assess and determine how to leverage the Radio Intelligence Controller (RIC) component of Open RAN to ensure timely spectrum sharing with commercial mobile networks.
   • It may be possible for research funding to be made available through NTIA Innovation Fund grants.
   • Develop automatic interfaces into commercial Radio Access Networks to inform operating status of base stations in response to federal agencies’ spectrum access needs.
4. Obtain Data on Sharing and Co-Existence Involving Federal and Non-Federal Users.
   • Obtain real-world data about co-existence interference, both between different federal users (e.g., DOD and the IC) and between federal and non-federal users (e.g., DOD and commercial mobile networks). Where possible, test a variety of power levels for commercial use to provide complete information about the ability of different types of use cases to co-exist with federal use.
5. Improve Security and Obfuscation.
   • Demonstrate how to manage sensitive USG systems in a secure environment and obfuscate USG systems in order to give federal users, including the military and the IC, confidence in the ability to operate securely and maintain operational security using dynamic spectrum sharing.
6. Refine Enforcement Mechanisms.
   • NTIA and FCC demonstrate they are able to identify and rapidly intervene in cases where a user of the band is transmitting unlawfully and causing harmful interference to other users.

Under the National Spectrum Strategy, there are two other efforts related to spectrum sharing that will occur in parallel with the DSS demonstration. These efforts, in addition to the DSS demonstration, will be critical to creating opportunities for more efficient use of spectrum:

• Assess the Economics, Incentives, and Public Interest Benefits of Spectrum Sharing: The USG, led by the FCC and NTIA (in consultation with relevant agencies and the Commerce Spectrum Management Advisory Committee), will undertake a parallel effort under National Spectrum Strategy Outcome 3.1(d) to analyze the economics, incentives, and public interest benefits associated with different models of spectrum sharing. This effort will:
  1. Provide a taxonomy of the technical/policy models and options for sharing spectrum.
  2. Conduct an economic analysis of those models of sharing, both the commercial incentives associated with different models and a risk framework, as well as the potential for incentives to encourage federal users to share more spectrum.
  3. Incorporate a discussion of the relationship between this economic analysis and the potential improvements in dynamic spectrum sharing into the final report, to provide a better understanding of how decisions made about both can result in greater commercial spectrum access on terms that will promote investment and innovation.
• Conduct Incumbent Informing Capability Audit: Some agencies’ spectrum usage may vary over time due to mission needs, notably related to national defense systems and the need for persistent spectrum access to enable maneuver space to detect and address potential threats. NTIA shall coordinate with such agencies to ensure that a spectrum audit provides a complete and accurate representation of mission-related spectrum use. The audit should identify classification considerations for affected agencies, which retain classification authorities for any data included in databases that are part of implementation of an audit. Coordination with affected agencies to address classification requirements would occur prior to implementation and transfer of data, including to ensure personnel with access have the requisite expertise and security clearance level required to handle and assess such data. Any disputes regarding whether the audit accomplishes this aim shall be resolved through the interagency process described in the national security memorandum of the President entitled 'Memorandum on Renewing the National Security Council System'.

Timelines and Deliverables

Beginning on 1 June 2024, the planned demonstration will have five phases:

• Phase 1, Technical Proposals/Requirements (60 days, currently underway with the lower 3 GHz Spectrum Pipeline Plan development submission due June 3, 2024):
  • During this phase, DOD and NTIA develop initial technical proposals and requirements, and coordinate these proposals and requirements with agencies that have equities to ensure they incorporate their received feedback and have their support.
  • For specific components of the DSS:
    1. DOD and NTIA ensure the framework being proposed is an improvement over current spectrum sharing technologies and techniques.
    2. Improving DOD’s ability to share with commercial Radio Access Networks and the ability of commercial networks to share: DOD develops a proposal, in consultation and coordination with FCC, NTIA, and industry partners.
    3. In coordination with NTIA and FCC, DOD develops a proposal for improvements in security and obfuscation.
    4. NTIA and FCC ensure that the proposal will also demonstrate the ability to identify and intervene when users are transmitting unlawfully.
• Phase 2, Obtaining Stakeholder Support, Securing Funding, Acquisition of Services, and Proposal Refinement (185 days, starts July 1, 2024):
  • DOD and NTIA share details of the proposals with outside stakeholders to receive feedback, garner support, and commitments to participate. Funding is obtained to support the demonstration and required support contracts are obtained/modified. Refinements to technical proposals are made and addition details developed. Timeline includes time to obtain funding from the Spectrum Relocation Fund.
• Phase 3, Prototyping (65 days, starts January 2, 2025):
  • DOD and NTIA acquire and test any capabilities, including technical capabilities, that are needed to complete each component of the demonstration.
• Phase 4, Tech Demonstration and Revision (91 days, starts March 8, 2025):
  • DOD and NTIA in coordination with a multistakeholder consortium consisting of government, industry, civil society, and academia, will conduct and complete the demonstration/analysis for each component of the demonstration.
  • For the technical workstreams, conduct iterative exercises under fully operational conditions to evaluate capability/prototype, which will include industry and government participants, and to obtain data on co-existence and interference.
• Phase 5, Public Release and Rollout (36 days, starts June 7, 2025, enabling completion on September 12, 2025):
  • DOD and NTIA, in coordination with a multistakeholder consortium (consisting of government, industry, and academia), make unclassified results of the demonstration available to the public.
  • DOD and NTIA, in coordination with the FCC, will complete a public report that discusses each demonstration and describes how each DSS solution may contribute, both individually and collectively with other components/demonstrations, to the advancement of Dynamic Spectrum Sharing in the future. This report will include an assessment of how DSS will impact DOD missions.
  • NTIA’s Institute for Telecommunication Sciences (ITS) will conduct an independent assessment of the initiative following the demonstration.

Given that international harmonization of spectrum use is critical to scaling commercial investments and building an ecosystem built around U.S. (rather than PRC) technology, the State Department, in coordination and cooperation with relevant agencies (DOD, NTIA, FCC) will build on the release and rollout of the DSS demonstration by conducting outreach to allies and partners to obtain support for the use of similar dynamic spectrum sharing mechanisms internationally.