On April 21, 2023, the FCC released the Policy Statement that will guide the FCC’s spectrum management policies going forward. The item was adopted at the April Open Meeting. The Policy is intended to provide guidance on future FCC decision-making in managing spectrum efficiently and effectively as the RF environment evolves. The Policy Statement is based on three broad core principles that will inform the Commission’s future actions and stakeholder expectations about interference from spectrally and spatially proximate sources:
- Interference Realities – this category recognizes the physical realities of interference that apply to transmitters and receivers in all spectrum based services. Specifically, the Draft Policy Statement recognizes that the following principles govern real-world interference scenarios:
- Interference and harmful interference are affected by the characteristics of both the transmitting service(s) and nearby receiving service(s) in frequency, space, and/or time.
i. The Commission expressly recognizes that receiver characteristics, particularly the dynamic range of desired and undesired power over which receivers are designed to operate, can be as important as transmitter characteristics in enabling efficient spectrum use and co-existence among different services.
- The electromagnetic environment is highly variable, and zero risk of occasional service degradation or interruption cannot be guaranteed.
i.The Commission notes that stakeholders should not have an expectation of 100% service availability when considering the likelihood of harmful interference
- Services should plan for the spectrum environment in which they intend to operate, the service they intend to provide, and the characteristics of spectrally and spatially proximate operations. Planning should be ongoing and account for changes in spectrum operating environments.
i. The Commission expressly states that it will expect service operators and equipment manufacturers to plan for current and future RF environments, including planning for equipment that is likely to be employed in spectrally proximate bands.
2. Shared Responsibilities – this category outlines the Commission’s expectations about the shared responsibilities of transmitter and receiver systems to co-exist with other services in spectrally proximate bands. Specifically, the Draft Policy Statement notes the Commission intends to consider the respective responsibilities of transmitting and receiving services and outlines the following expectations:
- Transmitters authorized for use in a given service should be designed to minimize the amount of their transmitted energy outside of the service’s assigned frequencies and authorizations.
i. The Commission reaffirms its policies on transmitters and notes that it expects further improvements in transmitter technologies. The Commission stated it will consider whether improved transmitters should be deployed in certain bands.
- Receivers authorized for use in a service should, as a general matter, be designed to mitigate interference from emissions from outside of their service’s assigned frequencies or channels.
i. The Commission expressly notes that operators and users should not assume that receivers designed for their original RF environment will remain categorically protected in the future as the Commission endeavors to authorize important new services.
ii. The Commission encourages stakeholders to design receivers that meet their services’ needs but will also mitigate impacts from undesired signals outside their services’ assigned frequencies.
iii. Going forward, the Commission plans to examine a number of factors related to receivers, including:
- whether receivers in an authorized service are sufficiently designed to mitigate undesired signals from outside of their service’s assigned frequencies, irrespective of location;
- the extent to which receivers can self-protect by minimizing performance degradation and employing filters with sufficient selectivity to withstand a range of undesired signal strength and unwanted emissions from spectrally proximate services;
- the state of the art in receivers deployment and the passage of time since relevant equipment was last upgraded;
- the scope and scale of legacy receivers in active operation; and
- the practicality and feasibility of upgrading to receivers that better withstand changes to the RF environment.
- Radio transmitter and receiver system operators and equipment manufacturers should plan for and design error tolerant systems, using good engineering practices, to mitigate degradation from interference.
i. The Commission notes that there is a range of engineering and design techniques available to satisfy the performance and reliability expectations of receiver equipment and that manufacturers and system operators should utilize them.
3. Data-Driven Regulatory Approaches to Promote Co-Existence – this category highlights the importance of reliable data in the Commission’s technical analysis of spectrum issues, including data about transmitters and receivers. Specifically, the Commission believes the following data will be essential:
- Relevant information about services’ transmitter and receiver standards, guidelines, and operating characteristics is needed to promote effective spectrum management and efficient co-existence.
i. The Commission notes it will consider whether to require disclosure of information on transmitter, receiver, and system characteristics associated with particular services. This information could include:
- For transmitters: information on the spectrum mask, emission type, power level, the range of antenna height above average terrain, anticipated antenna gain, antenna pattern, antenna direction, service coverage area, etc.
- For receivers: information could include details concerning the filter masks and blocking dynamic range to limit out-of-band signals carried through the receiver chain, interference resiliency, receiver selectivity, intermodulation rejection, noise figure/factor, and signal-to-interference-noise (SINR) requirements, as well as the extent of variation among receivers or receiver classes, and other information on legacy receivers that would enable an informed consideration of harmful interference concerns.
- Quantitative analyses of interactions between services that are fact- and evidence-based, sufficiently robust, transparent, and reproducible are needed to better inform spectrum management decision-making.
i. The Commission notes it will expect proponents of a harmful interference claim to supply sufficiently complete, transparent, and reproducible quantitative analytical models of the interactions between radio services, with respect to transmitter and receiver performance characteristics and the RF environment. The evidence should be representative of a large set of receivers and transmitters and capture real world operations.
ii. The Commission notes it will encourage, if necessary, cross-industry information sharing and collaboration, and consider using protective orders to gather the information.
- The Commission will explore, in future rulemakings, interference limits policies in particular spectrum bands to promote effective co-existence.
i. The Commission notes the following factors will be relevant when considering possible models for interference limits:
- the particular bands and services at issue;
- proceeding-specific technical considerations; and
- the rights and protections that might attach to incumbents and new entrants.
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