The determination of which public safety spectrum to use when building a public safety radio system is influenced by a number of factors including spectrum availability, the cost of implementation, agency coverage requirements and the need to ensure implementation will promote continued or new interoperability to system users and their neighboring agencies. Absent spectrum availability, the other requirements are seldom met and a project might never get off the ground. More and more systems today are selecting federal spectrum sharing to ensure that their implementation includes sufficient spectrum while establishing/retaining interoperability with local, state and federal responders.
Part 90 public safety agencies seeking to use federal spectrum to complement their existing spectrum would primarily be utilizing the VHF (150 MHz) or UHF (450-470 MHz) band. Federal agencies use both bands throughout the US and the extent to which they use each band in each state is not commonly known; for good reason, no publicly available database documenting specific federal spectrum use is available. In order for Part 90 agencies to share federal spectrum in their system implementation, a relationship and agreements between the applicant and federal agency(s) are required. Below are a few items that must be in place for the relationship between the applicant and the federal agency to share federal spectrum:

1. Enter into a Memoranda of Understanding with a federal agency. Federal spectrum is managed by the National Telecommunications Information Administration (NTIA) within its Interdepartment Radio Advisory Committee (IRAC). The IRAC assists the Assistant Secretary of Commerce in assigning frequencies to U.S. government radio stations and in developing policies and procedures for use of the spectrum. Its approval of any use of federal spectrum is critical to a public safety non-federal agency use of federal spectrum.
   When seeking to use federal spectrum, any Part 90 applicant agency must enter into a Memoranda of Understanding with a federal agency that is a member agency of the IRAC, outlining in detail how the spectrum would be used by the Part 90 licensee and how the non-federal use of the spectrum would benefit both federal and non-federal users. Such an MOU should acknowledge and outline, among other things, terms and conditions of the agreement, the responsibilities of both parties, an assurance of compliance to regulations by both parties, and a description outlining costs associated with participation and usage of the completed system by both parties. In accordance with the MOU, a narrative provided by the applying agency including details as to the type of system being built, the technologies being used (how the system uses P25, for example), how federal spectrum is to be used in that system, and specific tower locations of the radio system proposing federal spectrum use. Benefits of the system to federal entities ensuring interoperability between local, state, and federal users must be highlighted in the narrative as well.
   The Frequency Assignment Subcommittee, a subcommittee of the IRAC, reviews the proposal and may request the applicant agency to present before the subcommittee prior to approval. Such an in-person presentation is beneficial for both parties as it allows for questions to be asked of the applicant and for the applicant to get additional detail associated with such sharing agreements.
2. Coordinate channels with federal sponsor agency on a channel by channel, site by site basis. Once channel sharing has been approved by the IRAC, and the MOU between the applicant and its federal sponsor has been approved and signed, federal spectrum use is coordinated on a site by site basis. Federal channel availability may vary for different channels depending on how they are currently used by each federal agency in each area.
   In addition to channels being assigned to the applicant from the federal spectrum pool normally assigned to the federal sponsor, federal channels assigned to other entities can also be coordinated – but they must have the approval of the federal agency that uses the particular channel. In this instance the sponsor agency acts as the applicant’s advocate in the federal coordination process and the coordination for the use of that channel, if possible, is done between the federal agencies. If the federal agency receiving the sharing request benefits has users in the field that can benefit from system usage and retain interoperability with partner state and local agencies, this can contribute to successful sharing and coordination of federal spectrum.
3. Part 90 licensing of these channels still needs to be completed via ULS per FCC’s rules.The use of federal spectrum by non-federal agencies is permitted by FCC Rule 90.173 (c). Non-federal agencies to that want to use federal spectrum must obtain a license from the FCC. The licensing of federal spectrum by a non-federal agency does not require frequency coordination with a FCC-certified frequency coordinator.
   License applications for federal spectrum must contain written certification from a federal government agency that the use of the requested frequency(s) is required to improve or maintain interoperable communications between the applicant and the federal government. Upon receiving such applications, the FCC will submit the applications to the NTIA IRAC Frequency Assignment Subcommittee for approval. Keep in mind that, while the process for coordination is different for federal agencies, in any system where federal agencies use federal and non-federal spectrum, federal agencies have to obtain licenses/approval from NTIA to use non-federal spectrum in the same manner as Part 90 licenses have to obtain FCC licenses to use federal spectrum.

Good communication and dialogue between parties can result in beneficial system usage by all. Agencies working together towards a common goal can achieve communications capabilities and interoperability potential far beyond those that could be achieved absent the partnership. While coordination between state/local and federal agencies can be cumbersome and time consuming as well as “outside the box”, the reward from this type of coordination can include improved coverage, better response capabilities, the ability to access advanced technologies, and improved interoperability between participants and first responders to better protect those they serve.