IG expresses concern about NPSBN Band 14 coverage; FirstNet Authority, AT&T question some findings

FirstNet nationwide public-safety broadband network (NPSBN) effective coverage on 700 MHz Band 14 spectrum could be overstated, because the contracted signal-strength levels are well below the levels used by contractor AT&T for commercial purposes, according to a recent Office of Inspector General (OIG) management alert.

Both the FirstNet Authority and AT&T questioned portions of the OIG management alert on the topic, with both noting that the FirstNet users have access—with priority and preemption—to all AT&T commercial spectrum bands, not just the 700 MHz Band 14 airwaves licensed to the FirstNet Authority.

Entitled “The NPSBN Band 14 signal strength does not consistently provide adequate Band 14 service for first responders,” the management alert states that signal strength used by the FirstNet Authority to measure NPSBN coverage at the cell edge is “over 15 times less powerful” than the signal strength used by AT&T when measuring coverage for its commercial coverage via other spectrum bands.

“This could indicate that the total area AT&T reports as Band 14 coverage is overstated, and the services provided in the coverage area are not sufficient to allow first responders to effectively respond to emergencies,” according to the OIG management alert dated May 16. “This difference can adversely impact NPSBN services and ultimately affect public safety users’ ability to communicate with each other during emergencies.”

With this in mind, the OIG management alert proposes that the “FirstNet Authority should take steps to improve the signal strength at the edge of the coverage area through future NPSBN contract modifications and investments.”

Publicly available copies of the OIG management alert redact the exact signal-strength measurements—measured in decibel milliwatts (dBm)—collected during drive tests, apparently at the request of the FirstNet Authority, according to an OIG letter accompanying the management alert.

In a formal response to the OIG, AT&T claims that the management alert reached “unsubstantiated conclusions” and that the carrier “consistently represent(a) the signal-strength measurement in all public-facing maps”—a position that appeared to supported by the FirstNet Authority in its response to the OIG, although a redaction made it unclear.

In addition, the FirstNet Authority and the National Telecommunications and Information Administration (NTIA) commented that “the network performance exceeds the [minimal signal strength] significantly with the boundary of record,” according to the OIG management alert. The FirstNet Authority also noted that the signal strength at the cell edges that is being questioned by the OIG is fully compliant with the NPSBN contract signed in 2017.

Perhaps more troubling than signal-strength claim was the management alert’s assertion that minimal signal strength at the cell edge “was not sufficient to provide consistent, reliable service.” In particular, while downlink services in certain cell-edge scenarios tested in seven states were rated as “good,” voice-call success rates from cell-edge locations in four states were cited as “poor,” meaning “at least one in ten calls was either a failed attempt or dropped.”

This dynamic associated with the lower signal-strength level at the edge of cells “allowed AT&T to meet coverage requirements for the NPSBN contract without providing a high-performing network,” according to the OIG management alert.

Finally, the OIG management alert asserts that FirstNet Authority personnel said that AT&T offered to change the signal strength it used to report coverage, but the FirstNet Authority decided to keep the cell-edge signal-strength level as stated in the contract. NTIA and the FirstNet Authority claim that AT&T did not make a formal offer to make such a change, but the OIG remains critical of the inaction on the matter.

“We note that the FirstNet Authority had multiple opportunities in multiple contract modifications to negotiate an improved NPSBN measurement of coverage, and it did not do so,” the OIG management alert states.

While the OIG management alert cites the signal-strength measurement issues and proposes that the FirstNet Authority “take steps” to improve the situation, it does not request a formal action plan from the FirstNet Authority. Instead, the matter “was briefed to cognizant NTIA and FirstNet Authority officials in advance of issuance,” according to the management alert.

When asked for a response to the OIG management alert, a FirstNet Authority spokesperson provided the following statement to IWCE’s Urgent Communications.

“Coverage remains a top priority for the FirstNet Authority, and we will continue to invest in coverage enhancements to the network,” according to the FirstNet Authority statement. “We stand by the considerable amount of public safety infrastructure that has been deployed for FirstNet since 2018 and will continue to expand the network for America’s first responders.

“The FirstNet Authority developed the baseline transmission maps in consultation with the Federal Communications Commission and public-safety stakeholders in an open and transparent process. Since then, we have been committed to network improvement at every juncture. As a result, the initial buildout of the public-safety broadband network met or exceeded coverage targets for each state and territory.”

AT&T—the FirstNet Authority’s contractor tasked with building, maintaining and evolving the NPSBN for 25 years—was more outspoken in its response to the OIG alert. This included a lengthy statement attributed to Jim Bugel, president of AT&T’s FirstNet team, that was provided to IWCE’s Urgent Communications.

“The OIG’s alert unnecessarily creates confusion and ignores simple facts including, erroneously implying that signal strength measurements represented in coverage maps affect service availability and quality,” according to Bugel’s statement.

“As part of our commitment to unparalleled transparency, we consistently represent the signal strength measurement in all public-facing maps. And because FirstNet is an all-band network, first responders always have priority and preemption on both the FirstNet Authority’s Band 14 and AT&T’s commercial spectrum—regardless of how signal strength is measured on a map.”

Bugel’s statement notes that AT&T’s initial five-year buildout was “was completed on time, on budget and on task—including 35 percent more coverage than contractually required and significantly stronger signal strength at the Plan of Record network edge.”

In his statement, Bugel also cites key metrics like the NPSBN covering 2.97 million square miles, which is “250,000 square miles more than commercial networks available to public safety.” This includes coverage created by the installation of more than 1,000 towers built for FirstNet in locations where public safety asked for them, according to Bugel—many in areas that serve rural and tribal communities.

Bugel’s statement for IWCE’s Urgent Communications builds on the detailed response provided in a letter to the OIG office that claims the management alert “lacks essential context and reached unsubstantiated conclusions.” This letter cites three primary issues, that the alert:

• “Erroneously implies Band 14 signal strength measurements represented in coverage maps affect service availability and quality. This association leads to the faulty conclusion that merely adjusting the contract’s signal strength measurement would affect service. Rather, it would only result in a modified visual representation of coverage propagation on a map based on an alternate signal level. As part of our commitment to transparency, we consistently represent the signal-strength measurement in all public-facing maps.
• “Neglects recognition that AT&T met and exceeded Band 14 contractual compliance, and ignores the function of the dedicated FirstNet deployable network assets, available to public safety, to further extend FirstNet coverage – when and where public safety needs it. The Alert fails to acknowledge the significant expansion of coverage that occurred because of the initial phase of FirstNet Band 14 coverage buildout, which has been validated by the FirstNet Authority as complete.
• “Uses overly broad language, incorrectly insinuating conclusions about network edge coverage and applying findings to the entire network. In the Key Issues section, the Alert does not clearly state the OIG’s review is limited to the area on the very edge of cellular coverage.”

Bugel’s response letter to the OIG also notes that “Band 14 coverage is compliant with the contract requirements, and it far exceeds the original contract commitment. In fact, AT&T deployed Band 14 to reach several hundred thousand additional square miles for public safety’s dedicated use when needed.”

This OIG management alert is the result of an audit of the FirstNet Authority initiated almost two years ago. The audit’s objective was “to determine whether FirstNet Authority is ensuring that AT&T is achieving the desired results for network coverage for each state and territory,” according to an OIG letter to the FirstNet Authority dated June 28, 2022. At that time, the FirstNet Authority did not have a full-time CEO, as Ed Parkinson had resigned the position the previous month.