CSMAC Report Sees CBRS as Useful Sharing Model but Advises Changes
NTIA's Commerce Spectrum Management Advisory Committee is expected to vote Tuesday on a report that largely endorses the sometimes controversial approach to spectrum sharing used in the citizens broadband radio service band. Yet it also calls for improvements in how the CBRS model works. In addition, CSMAC will vote on a report from its 6G Subcommittee during a busy end-of-year meeting.
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“The CBRS band provides a unique opportunity to allow various non-federal entities to coexist with federal incumbents and other commercial users within a hybrid licensing mechanism, permitting a wide range of use cases across various users including fixed and mobile wireless operators, equipment vendors, and enterprise users,” the CBRS report says: “Across all stakeholders it was unanimously felt that the hybrid CBRS framework has resulted in commercial use without harmful interference to federal radiolocation and federal aeronautical radionavigation incumbents and that the lessons learned have been valuable to help fine tune this approach for the future.”
The report urges that commercial and government stakeholders work together “to drive timely improvements to rules, operational settings, and standards,” with an eye on informing the soon-to-be-created Interagency Spectrum Advisory Council. If CBRS is adopted for other frequency ranges, “the policy group framework and its stakeholder composition would need to be tailored to fit the unique circumstances of that frequency,” the paper says. The FCC first took up the CBRS band, which uses a three-tier sharing model primarily to protect Navy radars from harmful interference, almost a decade ago (see 1408250027). CTIA has questioned its viability as a model for other bands (see 2310180050).
CSMAC’s CBRS subcommittee acknowledges opposition from the wireless industry to broader use. “Nationwide wireless companies and a trade association stated the complexity of the band and the licensing and technical rules adopted have unintentionally inhibited network coverage and created unpredictable service quality in the band,” the report says: Carriers “stated these uncertainties, including the band’s power levels, have resulted in CBRS functioning only as a supplementary band that complements traditional licensed spectrum.”
“Given the early stage of its development, the state of 6G is currently enduring a clash between visionary ideas and practical realism,” the 6G report advises. Equipment makers and researchers are “driving the development of 6G visionary ideas on evolution of legacy as well as newly defined use cases, until service providers complement the process by providing operational and business requirements for their choice of use cases commensurate with their business objectives and plans,” the report says: “Challenges include making the business case and achieving the expected return on investment, the need for convergence of vision and the path forward, the risk of fragmentation, and regional divergence.”
The 6G report also focuses on the importance of spectrum sharing. It calls on NTIA to “engage early with federal incumbents with assignments in bands of particular interest for 6G, including mid-bands and above 95 GHz, to understand the type and degree of use and ability to share.”
NTIA should focus with the FCC on incumbent informing capability and other more sophisticated sharing technologies, the 6G report says. It advocates additional funding for the NTIA’s Colorado lab, the Institute for Telecommunication Sciences, which has focused on advanced sharing technologies. The report also urges more frequent updates to NTIA’s spectrum chart “adding additional, more detailed and granular data, e.g., location and time of use, describing federal spectrum uses and extending its compendium above 7.125 GHz to at least the THz range.”
NTIA should work with the FCC to facilitate innovation in terahertz spectrum for 6G “on an exploratory basis (e.g., waivers, possible additional unlicensed spectrum), considering that operations tend to be localized based on the propagation characteristics of this range,” the subcommittee advises.