4.9 GHz Commenters Focus on Improving Public-Safety Use, Encouraging Shared CII Use
Tuesday, December 07, 2021 | Comments
The FCC received a large swath of comments in response to its request for feedback on its eighth further notice of proposed rulemaking (NPRM) in regards to what actions it should take to improve use of the band.

The 4.9 GHz band has been dedicated to public-safety use since the early 2000s, but for many years, the FCC has been looking at ways in which it can address what it calls underuse of the band. Last year, the FCC adopted rules that would allow states to license portions of the band to non-public-safety entities.

However, several public-safety organizations including the Association of Public-Safety Communications Officials International (APCO) and the Public Safety Spectrum Alliance (PSSA), filed petitions to reconsider the new framework, expressing strong concerns about interference to public-safety users.

Earlier this year, the FCC vacated those rules and released the eighth FNPRM, which attempted to refocus the conversation on public-safety use of the band and asked for feedback on a variety of issues including the best ways to share the spectrum while protecting public safety, and how the band should be coordinated and managed, among other issues.

In the comments, most public-safety organizations said that formal frequency coordination is needed for the band and that any sharing of the band should be limited to critical infrastructure entities. Many public-safety entities were also against unlicensed use of the band. Meanwhile, several commercial communications organizations advocated for taking a similar approach to the Citizens Broadband Radio Service (CBRS) and 6 GHz band and using spectrum management systems to allow sharing.

APCO’s filing said that it appreciates the FCC’s work to refocus proceeding on public-safety use to the band.

“APCO supports the principles described in the FNPRM for unlocking the potential of the 4.9 GHz band by emphasizing public-safety needs and adopting a nationwide approach to promote a robust equipment market, drive down prices and costs and spur innovation,” APCO’s filing said. “APCO agrees that a comprehensive approach that emphasizes public-safety needs represents a superior path to unlocking the potential of the band than an approach that could lead to a patchwork of incompatible uses. Non-public-safety use should only be allowed if it can occur without causing harmful interference to public-safety operations in the band.”

APCO said that the commission should take immediate steps to make the band more attractive for public-safety use.

First, the organization said it agrees with the FCC’s tentative conclusion in the FNPRM that the band needs formal frequency coordination “to support interference protection and increase public safety confidence in the band.” APCO said that because of the diverse types of public-safety operations in the band, multiple approaches to coordination will be needed.

“Public-safety communications require reliable, interference-free access to spectrum,” the filing said. “Frequency coordination is the most effective way to promote public-safety use of the band and will complement any spectrum-sharing technologies that might be adopted for the band by increasing efficiency in spectrum use and preventing interference.”

APCO also argued that it is important for the FCC to increase flexibility for public-safety licensees in the band and agreed with the commission’s approach to favor technology neutral approach. However, the organization suggested going further including:
• Permit channel aggregation up to 50 megahertz,
• Don’t specify a band plan for the 4.9 GHz band allow public-safety frequency coordinators to assign channels in a way that maximizes spectrum interference and protects public safety from interference
• Allow unmanned aerial system (UAS) use
• Modify power restrictions to increase spectral efficiency and broadband use

“Each of these changes would benefit public-safety use without creating hurdles to additional changes for the band,” APCO said. “In adopting these changes, the commission should commit to preserving the 4.9 GHz band for public-safety use.”

Like APCO, which is a member, the National Public Safety Telecommunications Council (NPSTC) focused a large portion of its filing on ways that the FCC could improve management of the band and promote additional public-safety usage and new technologies. NPSTC first created a plan for the band in 2013 and has advocated that plan since.

NPSTC said it supports the FCC’s proposal of collecting more granular data on 4.9 GHz operations and combining that with a formal coordination structure, which will help mitigate interference and improve public-safety confidence in the band. NPSTC said that the commission’s Universal Licensing Service (ULS) should be the official database for that more granular information.

“The combination of the ULS database maintained by the commission on a nationwide basis, specific rules application nationwide on what granular data is required, the requirement for frequency coordination, and availability of accredited and knowledgeable coordinators, has worked well in other bands,” NPSTC’s filing said, noting that a similar approach would likely expand use of the 4.9 GHz band.

Whatever frequency approach is settled on for the band, NPSTC argued that it should protect a range of operations, including fixed and mobile, and new applications such as UAS and internet of things (IoT), for public safety.

NPSTC also argued that the FCC should take steps to promote those newer technologies and offered several recommendations on how to do so.

“While minor details may have been resolved in responding to successive NPRMs, over the past 10 years or so, NPSTC has recommended the commission change the rules to allow airborne operations, both manned and unmanned, and robotics in the 4.9 GHz band,” the filing said. “Unfortunately, previous commissions have failed to make these changes to accommodate additional types of public-safety operations and new technologies that if allowed, could have resulted in additional usage of the band.”

NPSTC also recommended allowing CII entities to share the band through frequency coordination to help meet their internal communications requirements.

“NPSTC recommends that CII be the only non-public-safety entities allowed to access the band,” the filing said. “There is a natural alignment between CII and public safety in preparation and response to certain natural and man-made disasters.”

The Enterprise Wireless Alliance (EWA) also encouraged the FCC to take a look at and adapt NPSTC’s plan for the 4.9 GHz band, noting while some shared spectrum models considered by the FNPRM would work, they would take a significant amount of time and effort to implement, which would delay progress in the band.

“Instead, the Commission need look no further than the National Public Safety Telecommunications Council (NPSTC) plan recommended in 2013, a plan that NPSTC has continued to endorse over the past eight years,” the EWA’s filing said. “That plan, a consensus proposal from the public-safety community, recommended that the 4.9 GHz band be shared with critical infrastructure industry (CII) entities. It proposed licensing and other refinements that would spur innovation in the band, improve coordination, and drive down costs. EWA, which represents a number of CII entities and other large business enterprise companies eager to invest in private broadband networks, has supported the NPSTC plan, while also recommending that the CII category be expanded to track the definition developed by the Department of Homeland Security.”

EWA said that it agrees with the FCC’s conclusion that the spectrum could be used more intensively. And the organization said that the spectrum should be licensed on an exclusive use and agreed with many other filers in that the ULS should be used as the main database for frequency purposes.

In a joint filing, the state of Maryland, the District of Columbia Statewide Interoperability Coordinator (SWIC), the Pennsylvania State Police (PSP), the Iowa Statewide Interoperable Communications System Board (ISICSB), the South Carolina Department of Administration and the state of Washington said a national framework for administrative and technical management of 4.9 GHz is necessary.

The states also argued that any technical rules for the band should be harmonized when practical, that ULS database would be the best source for storing data and the band and that any sharing of the band should be limited to CII entities.

The PSSA, which in the past has advocated for giving the 4.9 GHz band to the First Responder Network Authority (FirstNet Authority) to help meet future public-safety demand for 5G spectrum, said that the commission should give public safety priority use of the band. The PSSA said that secondary use should be permitted on the band, but it should be fully pre-emptible by public-safety agencies and must be compatible with public-safety use of the band.

The PSSA also argued that the FCC should pass rules that would allow public-safety entities to use 5G within the band. And to help manage the band, the PSSA argued that the spectrum should be assigned to a nationwide licensee, which would then designate a nationwide band manager.

“The 4.9 GHz band is the only mid-band spectrum assigned to public safety,” the PSSA filing said. “As such, it presents the best and, possibly, the only opportunity to deploy 5G services to public-safety agencies utilizing the low-latency, high-throughput and desirable propagation characteristics associated with mid-band spectrum. 5G has the potential to materially enhance the types of services first responders can access during emergencies, and the commission needs to assign mid-band spectrum to public safety that facilitates 5G applications, which is why the 4.9 GHz band rules are so critical.”

The American Association of State Highway and Transportation Officials (AASHTO), which is one four frequency coordinators certified by the FCC to administer radio spectrum for public safety, said that it supports the FCC’s attempts to expand 4.9 GHz systems to incumbent licensees that hold statewide licenses.

AASHTO said that state departments of transportation use mission-critical, point-to-point, interference-free, licensed spectrum for LMR and for backhaul to intelligent transportation system (ITS) devices and connected automated vehicle (CAV) applications.

“4.9 GHz microwave has proven to be a reliable, interference-limited, licensed spectrum solution that supports ITS and LMR dispatch communications,” AASHTO said in its filing. “4.9 GHz can be used to make connections such as permanent fixed point-to-point video surveillance, permanent fixed point-to-point/multipoint backhaul of broadband traffic originating from 700 MHz public-safety broadband networks and smart city applications that require LOS (line of sight) and NLOS (non-line of sight) … The 4.9 GHz spectrum for interconnecting LMR systems is also very cost effective and represents a large savings to eligible users, compared to other methods used in wide-area networks.”

AASHTO reiterated that it is opposed to the FCC opening the 4.9 GHz band to non-public eligible users but noted that it appreciates the FCC’s efforts to optimize use of the band. If the FCC chooses to allow other eligible entities into the spectrum, AASHTO said non-public-safety users should operate on a secondary basis to public-safety users.

“We opposed unlicensed use of the 4.9 GHz spectrum as this does not allow a formal mitigation process should harmful interference occur between licensed and unlicensed users,” the filing said. “Additionally, pursuing and resolving interference from unlicensed sources can be complex and lengthy, which requires cooperation and additional resources from the spectrum users.”

The California Department of Transportation (Caltrans) said it is opposed to sharing the spectrum with non-public-safety users in addressing an FCC proposal to provide public-safety priority and pre-emption in the FNPRM.

“Thorough system testing with conclusive results must be conducted prior to the commission formally adopting this concept,” the filing said. “Should public-safety priority and pre-emption be adopted, questions regarding reliability, standardized implementation and policies about how public-safety priority and pre-emption will be applied need to be addressed.”

In a joint filing, the American Power Institute (API) and the Energy Telecommunications and Electrical Association (ENTELEC) said that CII entities should have co-primary status in the band and that such status should not be tied to offering public-safety services because as defined in the FCC rules, CII are already seen as protecting safety of life, health or property. The two organizations noted that API had actually reached an agreement with public-safety organizations on shared use of the band between CII and public safety but the FCC rejected that agreement to move forward with the state licensing rules.

The California Office of Emergency Services (CalOES) said it supported the commission’s state licensing framework idea.

“Cal OES believes that state governments hold a unique position to determine the public-safety needs within their communities,” he said. “The commission’s decision to reconsider the seventh FNPRM potentially runs counter to the intended use of the spectrum.”

The department also said it is important to protect public safety from interference in the band and like other public-safety filers endorsed NPSTC’s “threshold degradation approach in the ANSI/TIA-10 standard.”

“This approach will create a standard for new or modified operations within the band and protect existing licensees from interference,” the filing said. “The adoption of this standard alone will not promote greater utilization of the band. Greater availability of technical data within the 4.9 GHz band has long been desired. Cal OES supports the requirement of providing the commission’s Universal Licensing System (ULS) with granular, operational data to mitigate interference issues.”

The Dynamic Spectrum Alliance (DSA) encouraged the FCC to adopt a “dynamic spectrum sharing” model as it did for the Citizens Broadband Radio Service (CBRS). The DSA said that would achieve the commission’s two-pronged approach goals of promoting more efficient public-safety use of the band while allowing commercial use on a secondary basis.

“To achieve these goals, we recommend that the commission implement a two- or three-tiered sharing approach where Tier 1 would consist of primary licensees in the band (including all incumbent users), while other non-public-safety users could access the band on a secondary basis, much like CBRS General Authorized Access users do today,” the filing said. “Use of a tiered sharing approach that leverages existing and proven automated database solutions, such as the spectrum access system (SAS) or automated frequency coordination (AFC) system, will assist the commission in achieving these goals.

Federated Wireless, which is one of the FCC’s certified SAS operators for the CBRS band, agreed with the DSA and said that a dynamic spectrum sharing solution would be the best to help meet the commission’s goals for the spectrum.

The Wireless Internet Service Provides Association (WISPA) also pushed a dynamic sharing solution similar to CBRS, arguing that such an approach would protect public-safety while also promoting further public-safety use of the band.

“The development of SAS in the CBRS band and the ongoing development of automated frequency coordination for standard power use of the 6 GHz band should be sufficient to overcome any misgivings the public-safety industry may have in the ability of a SAS to provide interference protection,” the filing said.

WISPA argued that other mechanisms would not be as effective in achieving the commission’s goals for the band.

Meanwhile, the New America Open Technology Institute (OTI) said the commission should allow unlicensed use of the band and implement automated frequency coordination (AFC) systems, like the ones used in the 6 GHz and CBRS bands, to manage interference.

“The ‘use-it-or-share-it’ approach to expanding use of an occupied but grossly underutilized band of spectrum that the commission adopted in fashioning a sharing framework for both CBRS and 6 GHz is a perfect fit for the 4.9 GHz band as well,” the OTI’s framework said. “Like incumbent Navy radar systems, current and future public-safety operations in the band, including emergency or priority uses, can be protected best by a tiered sharing model and an automated frequency coordination system designed to maximize overall use of the band. Open access transforms fallow spectrum into valuable public infrastructure for connectivity, supporting more available and affordable broadband services, particularly in less densely populated areas, and future innovation, such as industrial and agricultural Internet of Things (IoT) networks.”

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