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Category: Wireless Telecom Law

• Spectrum

With the growth of unmanned aircraft systems (UAS) and the increased demand for reliable control and non-payload communications (CNPC) for safe UAS operation, the FCC has established new frequency allocation rules in Part 88 for the Unmanned Aircraft Control Service (UACS). Specifically, the FCC allocated the 5030-5091 MHz band for the UAS Control and Non-payload Communications (CNPC) necessary to support unmanned flights. This article delves into the structure of frequency allocation within Part 88, comparing it to other dynamic frequency management systems like those in CBRS (Part 96), and discussing the safeguards in place to avoid interference with adjacent Radio Navigation Satellite Service (RNSS) and AeroMACS allocations. Learn More about Part 88 (UACS).

 

Frequency Allocation Structure in UACS

Under Part 88, the FCC introduced a new mechanism called the Dynamic Frequency Management System (DFMS), an automated coordination system designed to manage the shared use of spectrum in the 5030-5091 MHz band specifically for CNPC. According to FCC WT Docket No. 22-323, the DFMS allows UAS operators to submit spectrum requests for temporary, protected use in specific geographic areas for defined time periods. Unlike traditional fixed spectrum licenses, the DFMS enables UAS operations to dynamically access spectrum without requiring long-term, exclusive licensing. The aim is to efficiently support the short-term and dynamic communication needs of UAS while preserving spectrum availability for other users.

 

Dynamic Frequency Management System (DFMS) in UACS vs. Spectrum Access System (SAS) in CBRS

Both the DFMS for UACS and the Spectrum Access System (SAS) for the Citizens Broadband Radio Service (CBRS) use a dynamic approach to allocate spectrum access on an automated basis. However, there are notable differences between the two systems in scope and implementation. Learn More about CBRS Spectrum Allocation.

Purpose and Band Management:

• DFMS (UACS, Part 88): The DFMS is focused on providing interference-protected access to UAS operators for CNPC in the 5030-5091 MHz band. The system is optimized to support short-term, time-bound UAS operations, where each request corresponds to a specific flight.
• SAS (CBRS, Part 96): The SAS manages the 3550-3700 MHz CBRS band, supporting a tiered user structure including Incumbent, Priority Access License (PAL), and General Authorized Access (GAA) users. CBRS provides managed spectrum sharing between public and private entities with longer-term needs for spectrum access.

Automated Assignment and Interference Protection:

• DFMS: Requests to the DFMS must include operational details such as location, duration, and altitude to prevent interference. The DFMS dynamically adjusts assignments to avoid conflicts based on available spectrum and flight-specific parameters.
• SAS: The SAS system requires periodic heartbeat signals from CBRS devices (CBSDs) to confirm that spectrum assignments are active and interference-free. Through these heartbeat exchanges, the SAS can rapidly reallocate frequencies in response to higher-priority users, such as military radar.

Coordination and Flexibility:

• DFMS: Unlike CBRS, where heartbeats validate ongoing usage, DFMS requires advance coordination for each UAS operation. However, it offers flexibility by not mandating strict “flight plan” information, instead requiring basic details necessary for interference modeling and spectrum reservation. The DFMS tailors frequency assignments to match the geographic, temporal, and spectral needs of each UAS flight, supporting flexible, on-demand access.
• SAS: The SAS can modify frequency assignments based on real-time needs and regulatory priorities but operates without requiring detailed operational parameters.

 

Protection of Adjacent RNSS and AeroMACS Services

The UACS spectrum allocation and associated technical rules are carefully designed to minimize the risk of interference with critical adjacent services:

RNSS (5010-5030 MHz): Radio Navigation Satellite Service is protected by technical requirements that include limits on out-of-band emissions (OOBE) as specified in RTCA DO-362A standards. Additionally, the separation between UACS (5030-5091 MHz) and RNSS frequencies minimizes the potential for interference, ensuring safe and reliable satellite navigation.

AeroMACS (5000-5030 MHz, 5091-5150 MHz): AeroMACS, a broadband service supporting airport surface operations, is allocated to both lower and upper adjacent bands around UACS frequencies. To prevent interference with AeroMACS operations, UACS deployments must adhere to specific antenna siting and OOBE limits in accordance with RTCA standards. The FAA guidelines recommend that UAS ground station antennas avoid pointing directly toward AeroMACS base stations at airports, reducing the likelihood of interference in critical airport areas. Learn more about AeroMACS.

Guard Bands: While specific guard bands have not been mandated, the FCC has structured UACS spectrum usage and technical requirements to provide adequate buffer zones between RNSS, AeroMACS, and UAS CNPC, limiting potential cross-service interference.

 

Key UACS Regulatory Parameters for DFMS

Under Part 88, the DFMS is required to implement several regulatory parameters to manage the shared spectrum for UAS operators:

• Frequency Assignments: DFMS assignments are made for limited durations and specific geographic areas, with a maximum flight duration of 24 hours per assignment and a restriction on advance reservation to seven days.
• Automation and Coordination: DFMS administrators must ensure automated responses to spectrum requests and coordinate with any other DFMS systems to prevent conflicting assignments.
• Flexible Request Processing: DFMSs are permitted to adjust the frequency assignment terms based on availability and interference considerations, ensuring that UAS operators receive reliable access without monopolizing spectrum resources.

 

Conclusion

The FCC’s Part 88 allocation and DFMS framework represent a significant step in supporting the UAS industry by creating a dynamic, automated system to manage frequency access in the 5030-5091 MHz band. Drawing inspiration from the CBRS SAS model, the DFMS provides a tailored approach for UAS operations with time- and location-based frequency assignments. Through careful spectrum allocation, coordination requirements, and built-in protections for adjacent RNSS and AeroMACS services, Part 88 aims to balance the needs of UAS operators and existing users in adjacent bands, allowing for efficient, secure, and reliable unmanned aircraft control communication.

 

Contact Us

Kama Thuo, PLLC is a Wireless Telecommunications Law firm with expertise in FCC regulatory counseling and spectrum allocation. Contact us to see how we can assist with your wireless regulatory needs.

 

 

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Category: Wireless Telecom Law

• Spectrum

The Citizens Broadband Radio Service (CBRS) is a shared spectrum in the 3.5 GHz band (3550-3700 MHz) in the United States, designed to enable efficient use of mid-band spectrum for wireless broadband and other applications. Learn More. 

The CBRS framework allows for dynamic, hierarchical spectrum sharing among three levels of users to maximize spectrum access and minimize interference. Here’s an overview of the frequency allocation in CBRS and the role of the heartbeat in maintaining the system’s functionality:

1. CBRS Frequency Allocation and Access Tiers

The CBRS band operates with three tiers of users:

• Incumbent Access: This tier includes federal/government users, such as the U.S. Navy, and other pre-existing users, like satellite ground stations, who have priority access to the band. They can operate without interference from other users, and the SAS protects this tier by dynamically managing other users when incumbents are active.

• Priority Access License (PAL): Licensed to specific users (such as wireless carriers) for exclusive use in specific geographic areas. PAL licenses are auctioned by the FCC, providing license holders with access to 10 MHz channels within the 3550-3650 MHz portion of the CBRS band. PALs must still defer to Incumbent users, ensuring they don’t interfere with Incumbent operations.

• General Authorized Access (GAA): This tier provides open access to any CBRS-compliant device (CBSD) without the need for a license. GAA users can operate in both the 3550-3650 MHz (if unassigned by PALs) and 3650-3700 MHz bands, but they must avoid interfering with PAL and Incumbent users.

2. Spectrum Access System (SAS)

The SAS is a cloud-based coordination and control system that manages access to the CBRS band across these tiers. The SAS dynamically assigns frequencies and power levels to CBSDs based on current spectrum conditions, ensuring non-interference with higher-priority users. Each CBSD must register with the SAS, which then authorizes it to transmit based on available frequencies and geographic location.

3. The Heartbeat Process

To maintain real-time management of CBRS frequencies and ensure compliance with Incumbent and PAL protections, the SAS and CBSDs engage in a heartbeat exchange. Here’s how the heartbeat works in CBRS:

• Periodic Authorization Check: The CBSD sends a heartbeat signal to the SAS at a defined interval (typically every 5-60 seconds), confirming its continued authorization to operate on a specific frequency and at a particular power level. This keeps the SAS informed of active devices and ensures they are not creating harmful interference.

• Dynamic Reallocation: If a higher-priority user, like an Incumbent, begins using the band within the CBSD’s operating area, the SAS will respond to the next heartbeat with instructions for the CBSD to change frequency, lower power, or cease operations entirely to protect the Incumbent’s use.

• Disconnection Detection: If the SAS stops receiving heartbeats from a CBSD, it assumes the device has disconnected or ceased transmission, and the frequency it was using can be reallocated. This minimizes unused spectrum and prevents interference with other devices.

The heartbeat system is central to the CBRS’s ability to share spectrum dynamically while protecting priority users and optimizing spectrum usage across all tiers.

4. Benefits of the CBRS Framework

• Efficient Spectrum Use: The tiered, SAS-coordinated approach allows multiple users to share the same frequencies effectively, maximizing the use of the valuable mid-band spectrum.
• Interference Management: Through the heartbeat mechanism and SAS oversight, the CBRS framework ensures priority users are protected from interference while allowing flexible access for others.
• Cost-Effective Expansion of Wireless Services: By allowing GAA access, the CBRS band enables smaller operators, enterprises, and new entrants to utilize high-quality spectrum for applications like private LTE/5G networks without having to buy spectrum at auction.

Contact us for help with spectrum allocation in Part 96 (CBRS) or any other FCC Radio Service, and for other wireless telecom legal issues. 

Details

Category: Wireless Telecom Law

• Compliance
• Cerification

The Broadband DATA Act sets forth specific requirements for BDC (Broadband Data Collection) filings, outlining the necessary certifications and qualifications. Compliance with certification criteria is crucial to ensuring the accuracy and reliability of data submissions.

Below are the requirements for certification of BDC:

Corporate Officer Certification:

A fundamental requirement for BDC filings is the inclusion of a certification signed by a corporate officer of the provider. This certification entails a thorough examination of the submission's information. The corporate officer must affirm, to the best of their actual knowledge, information, and belief, that all statements of fact within the submission are true and correct.

Qualified Engineer Certification:

In addition to the corporate officer certification, each BDC filing must feature a certification of accuracy by a qualified engineer employed by the provider. The engineer must possess direct knowledge of or responsibility for the generation of the provider's BDC filing. Like the corporate officer certification, the engineer must validate that all statements of fact in the submission are true, accurate, and aligned with the provider's ordinary course of network design and engineering.

The qualified engineer certifying the BDC filing must meet one of the following qualifications:

1. Be a certified Professional Engineer (P.E);
2. Be a Corporate engineering officer with a Bachelor of Science in Engineering (BSE) with direct knowledge of, and responsibility for, the carrier’s network design and construction to certify that the BDC submission is in accordance with the service provider’s ordinary course of network design and engineering; or
3. Due to the 2022 Limited Waiver and its 2023 Extension, an "otherwise qualified engineer" is defined as:
   • An engineer who has either obtained a bachelor's or advanced degree in fields related to electrical engineering, electronic technology, or a comparable technical discipline, along with a minimum of seven years of applicable experience in broadband network design and/or performance; 
   • Alternatively, it could also refer to an engineer who has received specialized training in areas relevant to broadband network engineering and design, deployment, and/or performance, coupled with at least ten years of relevant experience in broadband network engineering, design, and/or performance.

Maintaining Additional Network Information:

Providers opting for certification by an "otherwise qualified engineer" must keep additional network information for the applicable BDC filing date. This data may be requested by the Commission for validation purposes, emphasizing the importance of data integrity and transparency. The data requirements differ based on the service offered. You can find the specific guidelines for the data to be retained in the Data Specifications for Provider Infrastructure Data outlined in the Challenge, Verification, and Audit Processes available here:

By engaging certified corporate officers and qualified engineers, providers contribute to the validity of the data reported, ultimately supporting the consistency and quality of broadband network design and performance assessments.

It is important to note that all BDC submissions, even those endorsed by an "otherwise qualified engineer," must still include a certification from a corporate officer.

More Information:

For more detailed information and specific requirements, providers are encouraged to refer to the detailed specifications outlined in the Broadband DATA Act and related documentation provided by the FCC.

We partner with licensed engineering firms experienced in RF such as Rfwel Engineering who are qualified under either criteria. Please contact us if you have legal questions regarding BDC certifications.

Details

Category: Wireless Telecom Law

• Compliance

The Broadband Data Collection (BDC) is a process by the Federal Communications Commission (FCC) to collect data on broadband availability across the United States as per the Broadband DATA Act that sets forth specific certification requirements. It includes information from providers on their infrastructure, service availability, and subscription data. This data is used to create the National Broadband Map, which helps identify areas with limited or no broadband access.

The Data Specifications for Provider Infrastructure Data in the Challenge, Verification, and Audit Processes outline the specific requirements for how providers should submit their infrastructure data during the different stages of the BDC process:

• Challenge Process: This is when individuals, communities, and other stakeholders can dispute the accuracy of the broadband data shown on the National Broadband Map. The data specifications detail how providers must respond to these challenges and provide supporting evidence for their infrastructure data.
• Verification Process: This is an FCC-led process to verify the accuracy of the broadband data submitted by providers. The data specifications outline the criteria the FCC will use to assess the accuracy and completeness of the data, including the types of supporting documentation providers need to submit.
• Audit Process: This is a more in-depth examination of a provider's broadband data. The data specifications outline the specific procedures and requirements for providers to comply with during an audit.

Key Elements:

1. Data Files Submission: Providers must submit specific data files when responding to mobile challenges or verification inquiries. These files include detailed information about cell sites, antennas, and other infrastructure elements used to provide service in the challenged area. This data helps the FCC verify the accuracy of the coverage maps and resolve any disputes about service availability.

2. On-the-Ground Test Data: Providers can respond with on-the-ground test data in addition to infrastructure data. This involves conducting speed tests at specific locations within a hexagonal cell geography based on the H3 geospatial indexing system. These tests must meet specific geographic, temporal, and testing thresholds to be valid.

3. Verification Process: The FCC uses a variety of data sources to identify areas for verification inquiries, including crowdsourced data, third-party data, and FCC staff evaluations. Providers must submit data for a statistically valid sample of areas within the targeted region if their coverage data is questioned. The FCC evaluates factors such as test reliability, RF link budgets, and infrastructure data accuracy during the verification process.

4. Crowdsourced Data: Consumers can submit crowdsourced data through the FCC Speed Test app or approved third-party applications. This data, which must meet specific parameters and metrics, is used to supplement the FCC’s verification efforts and is publicly available once a critical mass is reached. The FCC initiates inquiries based on automated processes that highlight areas for further review​.

Below is an example National Broadband Map location summary for outdoor stationary mobile broadband. You can navigate to the FCC mobile challenge portal directly from the map (e.g., to challenge that you are not receiving 35 Mbps download speed and 3 Mbps upload speed on 5G NR at this location as indicated below).

 

For more detailed information and to access the specific data specifications, you can visit the FCC’s Broadband Data Collection resources page here.

For information on broadband coverage, you can contact wireless engineering firms such as Rfwel Engineering. You may also contact us for legal advice regarding your broadband coverage challenge.

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