The radio frequency spectrum is the resource that makes possible wireless communication and supports a vast array of commercial and government services. Federal, state, and local agencies use spectrum to fulfill a variety of government missions, such as national defense, air- traffic control, weather forecasting, and public safety. DOD uses spectrum to transmit and receive critical voice and data communications involving military tactical radio, air combat training, precision-guided munitions, unmanned aerial systems, and aeronautical telemetry and satellite control, among others. The military employs these systems for training, testing, and combat operations throughout the world. Commercial entities use spectrum to provide a variety of wireless services, including mobile voice and data, paging, broadcast television and radio, and satellite services. In the United States, responsibility for spectrum management is divided between two agencies: FCC and NTIA. FCC manages spectrum for nonfederal users, including commercial, private, and state and local government users, under the Communications Act. NTIA manages spectrum for federal government users and acts for the President with respect to spectrum management issues as governed by the National Telecommunications and Information Administration Organization Act. FCC and NTIA manage the spectrum through a system of frequency allocation and assignment. Allocation involves segmenting the radio spectrum into bands of frequencies that are designated for use by particular types of radio services or classes of users. (Fig. 1 illustrates examples of allocated spectrum uses, including DOD systems using the 1755-1850 MHz band.) In addition, spectrum managers specify service rules, which include the technical and operating characteristics of equipment. Assignment, which occurs after spectrum has been allocated for particular types of services or classes of users, involves providing users, such as commercial entities or government agencies, with a license or authorization to use a specific portion of spectrum. FCC assigns licenses within frequency bands to commercial enterprises, state and local governments, and other entities. Since 1994, FCC has used competitive bidding, or auctions, to assign certain licenses to commercial entities for their use of spectrum. Auctions are a market- based mechanism in which FCC assigns a license to the entity that submits the highest bids for specific bands of spectrum. NTIA authorizes spectrum use through frequency assignments to federal agencies. More than 60 federal agencies and departments combined have over 240,000 frequency assignments across all spectrum bands, although 9 departments, including DOD, hold 94 percent of all frequency assignments for federal use. Pub. L. No. 103-66, § 6001,107 Stat. 312 (1993) (OBRA-93) amended by Pub. L. No. 105-33, § 3002, 111 Stat. 251(1997) (BBA-97), codified as amended at 47 U.S.C. § 923. enforcement purposes, may not be compatible with commercial technology, and therefore agencies have to work with vendors to develop equipment that meets mission needs and operational requirements. In 2004, the Commercial Spectrum Enhancement Act (CSEA) established a Spectrum Relocation Fund, funded from auction proceeds, to cover the costs incurred by federal entities that relocate to new frequency assignments or transition to alternative technologies. OMB administers the Spectrum Relocation Fund in consultation with NTIA. CSEA streamlined the process by which federal agencies are reimbursed for relocation costs and requires FCC to notify NTIA at least 18 months in advance of beginning an auction of new licenses of spectrum identified for reallocation from federal to nonfederal use. It also requires NTIA to provide estimated cost and transition timing data to FCC, Congress, and GAO at least 6 months prior to the auction, and requires that auctions recover at least 110 percent of these estimated costs. CSEA was amended by the Middle Class Tax Relief and Job Creation Act of 2012, further easing relocation by (1) allowing agencies to use some of the funding for advance planning and system upgrades, (2) extending the reimbursement scheme to sharing as well as relocation expenses, and (3) requiring agencies to submit transition plans for relocation (or sharing) for interagency management review of the costs and timelines associated with the relocation. The auction of spectrum licenses in the 1710-1755 MHz band was the first with relocation costs to take place under CSEA. CSEA designated 1710-1755 MHz as “eligible frequencies” for which federal relocation costs could be paid from the Spectrum Relocation Fund, which is funded Twelve federal agencies by the proceeds from the auction of the band.previously operated communications systems in this band, including DOD. NTIA and FCC jointly reallocated the 1710-1755 MHz band for nonfederal use, and FCC designated the spectrum for Advanced Wireless Services (AWS). In September 2006, FCC concluded the AWS-1 auction of licenses in the 1710-1755 MHz band. In accordance with CSEA, a portion of the auction proceeds associated with the 1710-1755 MHz band is currently being used to pay spectrum relocation expenses. In addition to the 1710-1755 MHz band, the wireless industry has expressed interest in the 1755-1850 MHz band, largely because the band offers excellent radio wave propagation, enabling mobile communication links. The federal government has studied the feasibility of relocating federal agencies from the 1755-1850 MHz band on several occasions. For example, in March 2001, NTIA issued a report examining the potential to accommodate mobile wireless services in the broader 1710- 1850 MHz band. The report was largely based on input from other federal agencies, including a DOD study. NTIA found that unrestricted sharing of the 1755-1850 MHz band was not feasible and that considerable coordination between industry and DOD would be required before any wireless systems could operate alongside federal systems in the band. In August 2001, we also found that more analysis was needed to support spectrum use decisions in the 1755-1850 MHz band, largely because major considerations either were not addressed or were not adequately addressed in DOD’s study. These considerations included complete technical and operation analyses of anticipated spectrum interference; cost estimates supporting DOD reimbursement claims; spectrum requirements supporting future military operations; programmatic, budgeting, and schedule decisions needed to guide analyses of alternatives; and potential effects of U.S. reallocation decisions upon international agreements and operations. At the end, a decision was made to reallocate just the 1710-1755 MHz band to minimize the impact on federal capabilities. Activity surrounding the rest of the band (i.e., the 1755-1850 MHz band) did not resurface until October 2010 when NTIA’s Fast Track study identified the band for possible reallocation. In June 2010, the administration issued a presidential memorandum titled “Unleashing the Wireless Broadband Revolution” directing NTIA to collaborate with FCC to make a total of 500 MHz of federal and nonfederal spectrum available for wireless broadband within 10 years. Responding to the President’s initiative, in October 2010, NTIA published a plan and timetable to make available 500 MHz of spectrum for wireless broadband. This plan and timetable specified that candidate bands would be prioritized for detailed evaluation to determine the feasibility of vacating the bands to accommodate wireless services. In January 2011, NTIA selected the 1755-1850 MHz band as the priority band for detailed evaluation for relocation. DOD and other affected agencies provided NTIA their input on the spectrum feasibility study for the 1755-1850 MHz band, and NTIA subsequently issued its assessment of the viability for accommodating commercial wireless broadband in the band in March 2012. Most recently, the President’s Council of Advisors on Science and Technology published a report in July 2012 recommending specific steps to ensure the successful implementation of the President’s 2010 memorandum. The report found, for example, that clearing and vacating federal users from certain bands was not a sustainable basis for spectrum policy largely because of the high cost to relocate federal agencies and disruption to federal missions. The report recommended new policies to promote the sharing of federal spectrum. The sharing approach has been questioned by CTIA–The Wireless Association and its members, which argue that cleared spectrum and an exclusive-use approach to spectrum management has enabled the U.S. wireless industry to invest hundreds of billions of dollars to deploy mobile broadband networks resulting in economic benefits for consumers and businesses. Actual costs to relocate communications systems for 12 federal agencies from the 1710-1755 MHz band have exceeded original estimates by about $474 million, or 47 percent, as of March 2013. Table 1 compares estimated relocation costs with the actual costs based on funds transferred to federal agencies in support of the 1710-1755 MHz band relocation effort. OMB and NTIA officials expect the final relocation cost to be about $1.5 billion compared with the original estimate of about $1 billion. In addition, NTIA expects agencies to complete the relocation effort between 2013 and 2017. The original transfers from the Spectrum Relocation Fund to agency accounts were made in March 2007. Subsequently, some agencies requested additional monies from the Spectrum Relocation Fund to cover relocation expenses. Agencies requesting the largest amounts of subsequent transfers include the Department of Justice ($294 million), the Department of Homeland Security ($192 million), and the Department of Energy ($35 million). Total actual costs for the 1710-1755 MHz transition exceeded estimated costs, as reported to Congress in 2007, for many reasons, including: Unforeseen challenges: Agencies encountered various unforeseen challenges when relocating systems out of the 1710-1755 MHz band. For example, according to NTIA officials, one agency needed to upgrade its radio towers to comply with new standards adopted after the towers were built. The agency requested additional monies from the Spectrum Relocation Fund to cover the cost of upgrading its towers, which had not been part of the agency’s original relocation estimate. Unique issues posed by specific equipment location: According to NTIA, some federal government communications systems are located in remote areas.