In 2020, the Federal Communication Commission (FCC) adopted rules to expand unlicensed operations in the 6 GHz band, opening up access to 1200MHz of spectrum to be shared by heterogeneous public and private network operators. This spectrum is anticipated to significantly expand access to much-needed mid-band spectrum for mobile and fixed broadband wireless uses.
To manage the co-existence of these unlicensed users with legacy systems such as commercial microwave point-to-point links, the FCC’s rules provide for a mix of interference mitigation strategies, including geo-location (geo-fencing) to restrict unlicensed users in certain locations, different power limits for indoor and outdoor operations, and coordination of spectrum use via Automated Frequency Coordination (AFC) systems. Akin to the role of the Spectrum Access Systems (SAS) operating in the CBRS 3.5 GHz band, the AFCs are tasked with enabling automated spectrum sharing between unlicensed devices and incumbent users. When operating outdoors, unlicensed devices (Standard Power Access Points) are required to communicate to an AFC certain relevant operating details that the AFC uses to then provide operational parameters to the unlicensed devices (e.g., available channels) such that no harmful interference is caused to protected incumbents. Unlike the SAS, the multiple AFCs do not coordinate their activities and so are unable to take account of aggregate interference levels. Additionally, the AFCs spectrum sharing and co-existence solutions are based on interference models and regulatory rules that may prove to be too conservative and a poor fit for some actual usage scenarios.
Spectrum Consumption Models (SCMs), an IEEE-standards-based approach for describing the RF requirements of radios in a spectrum space and Spectrum Access Agreements (SAAs) that make use of SCMs provide a viable toolset for examining the efficiency and efficacy of the existing FCC 6GHz rules framework. In this paper, we review the 6 GHz rules and show how they could be implemented within a SCM framework. We also show how greater use of the 6GHz spectrum could be possible if more information was exchanged with an AFC using the standards-based framework of SCMs. We explore the policy and economic impacts of enabling this flexibility. For example, this approach could lead to higher computational costs for an AFC, which would need to be balanced with the benefits of increased spectrum utilization. Through the application of our 6GHz simulation platform and the SCM/SAA framework, we are able to suggest efficiency-enhancing reforms to the existing 6GHz FCC rules. We support those recommendations with an analysis of the economic and regulatory implications on key stakeholders in this important new band for wireless services.