Bridging the digital divide is the FCC’s top priority, and accurate broadband deployment data are critical
to this mission. As part of the Commission’s ongoing effort to reform universal service funding of mobile
wireless services and focus subsidies on unserved areas rather than on areas that already have service, the
Commission unanimously adopted a new data collection of 4G Long-Term Evolution (LTE) mobile
broadband coverage maps and a challenge process to determine areas eligible for support in the Mobility
Fund Phase II (MF-II) auction. The largest mobile providers supported both this data collection and the
challenge process. After mobile providers submitted coverage maps to the Commission and during the
challenge process, some raised concerns regarding the accuracy of the maps submitted by providers.
Based on these parties’ complaints and its own review of the record, staff became concerned that maps
submitted by Verizon, U.S. Cellular, and T-Mobile overstated their coverage and thus were not accurate
reflections of actual coverage.
Mobile providers are responsible for submitting accurate coverage maps in accordance with the FCC’s
rules and orders. In response to these concerns and based upon a preliminary staff review of the
challenger data, on December 7, 2018, the Commission launched an investigation into whether one or
more major mobile providers violated the requirements of the one-time collection of coverage data. The
investigation was led by the Rural Broadband Auctions Task Force in coordination with the Office of
Economics and Analytics, Enforcement Bureau, Wireless Telecommunications Bureau, Wireline
Competition Bureau, and the Office of Engineering and Technology. FCC staff initially requested info
directly from several providers in order to understand providers’ mapping processes, and later issued
subpoenas to Verizon and U.S. Cellular.
The Commission dispatched Enforcement Bureau field agents to conduct speed tests of the Verizon,
U.S. Cellular, and T-Mobile networks. Commission field agents measured on-the-ground network
performance in 12 states across six drive test routes,1 conducting a total of 24,649 tests and driving
nearly 10,000 miles in the course of this testing. Field agents also conducted 5,916 stationary speed
tests at 42 distinct locations in nine states. Commission staff analyzed the speed test data from both
the staff tests and MF-II challengers’ speed tests and compared these test data with the maps submitted
for the MF-II data collection as well as with maps providers had previously submitted to the Commission
in other proceedings. This report documents the steps and processes undertaken by staff to investigate the
coverage maps, analyze speed tests taken by staff and submitted by challengers, and explains why
discrepancies may exist between the submitted maps and actual coverage.
Through the investigation, staff discovered that the MF-II coverage maps submitted by Verizon, U.S.
Cellular and T-Mobile likely overstated each provider’s actual coverage and did not reflect on-the-
ground performance in many instances. Only 62.3% of staff drive tests achieved at least the minimum
download speed predicted by the coverage maps—with U.S. Cellular achieving that speed in only 45.0%
of such tests, T-Mobile in 63.2% of tests, and Verizon in 64.3% of tests. Similarly, staff stationary tests
showed that each provider achieved sufficient download speeds meeting the minimum cell edge
probability in fewer than half of all test locations (20 of 42 locations). In addition, the staff was unable
to obtain any 4G LTE signal for 38% of drive tests on U.S. Cellular’s network, 21.3% of drive tests on
T-Mobile’s network, and 16.2% of drive tests on Verizon’s network, despite each provider reporting
coverage in the relevant area.
The Commission and the public must be able to rely on the deployment data that providers submit to
the Commission. Inaccurate data jeopardize the ability of the FCC to focus our limited universal service
funds on the unserved areas that need the most support. Accordingly, and considering the findings in
this report, the Rural Broadband Auctions Task Force makes the following recommendations:
First, the Commission should terminate the MF-II Challenge Process. The MF-II coverage maps
submitted by several providers are not a sufficiently reliable or accurate basis upon which to complete
the challenge process as it was designed. The MF-II Challenge Process was designed to resolve coverage
disputes regarding generally reliable maps; it was not designed to correct generally overstated coverage
maps.
Second, the Commission should release an Enforcement Advisory on broadband deployment data
submissions, including a detailing of the penalties associated with filings that violate federal law, both
for the continuing FCC Form 477 filings and the new Digital Opportunity Data Collection. Overstating
mobile broadband coverage misleads the public and can misallocate our limited universal service funds,
and thus it must be met with meaningful consequences.
Third, the Commission should analyze and verify the technical mapping data submitted in the most
recent Form 477 filings of Verizon, U.S. Cellular, and T-Mobile to determine whether they meet the
Form 477 requirements. Staff recommends that the Commission assemble a team with the requisite
expertise and resources to audit the accuracy of mobile broadband coverage maps submitted to the
FCC. The FCC should further consider seeking appropriations from Congress to carry out drive testing,
as appropriate. While Form 477 currently affords providers significant discretion in determining the
extent of their mobile broadband coverage, this discretion does not encompass reporting inaccurate
mobile coverage across extended areas in which consumers cannot receive any wireless signal
whatsoever.
Fourth, the FCC should adopt policies, procedures, and standards in the Digital Opportunity Data
Collection rulemaking and elsewhere that allow for submission, verification, and timely publication
of mobile broadband coverage data. Mobile broadband coverage data specifications should include,
among other parameters, the minimum reference signal received power (RSRP) and/or minimum
downlink and uplink speeds, standard cell loading factors and cell edge coverage probabilities,
maximum terrain and clutter bin sizes, and standard fading statistics. Providers should be required
to submit actual on-the-ground evidence of network performance (e.g., speed test measurement
samplings, including targeted drive test and stationary test data,) that validate the propagation model
used to generate the coverage maps. The Commission should consider requiring that providers assume
the minimum values for any additional parameters that would be necessary to accurately determine
the area where a handset should achieve download and upload speeds no less than the minimum
throughput requirement for any modeling that includes such a requirement.
Because detailed information on propagation model parameters and deployed infrastructure is
necessary to fully verify the engineering assumptions inherent in mobile coverage data, the FCC should
collect specific information used in the models, including the locations and specific characteristics of
certain cell sites used for mobile wireless service, the modeling software used, the entire link budget,
the sources of terrain and clutter data, and clutter values. The Commission should require engineering
certifications of mobile broadband deployment data submissions. And the Commission should convene
a workshop of stakeholders on best practices for the generation and submission of accurate mobile
broadband deployment data including speed testing methodologies
