Extension of Commercial Shared Spectrum Frameworks to Passive/Active Coexistence
Various centralized cloud-based spectrum sharing frameworks have been deployed or are under development to support spectrum sharing among active services. One example includes TV White Space (TVWS), which supports sharing among broadband, television, wireless microphones, and other services. Another example is the US Citizens Broadband Radio Service (CBRS), which manages interference from two tiers of underlay broadband services into government radar, which is primary incumbent service. Additionally, in the US and other countries, the 6GHz band is about to be shared between incumbent services (primarily fixed point-to-point systems) and unlicensed devices. The unifying characteristic of these sharing arrangements is that they are all managed by a centralized cloud-based service: TVWS database, Spectrum Access System (SAS), and Automated Frequency Controller (AFC), respectively. These systems are responsible for knowing when and where incumbent systems are operating, and managing the emissions from underlay services so as not to interfere. There is no reason that similar systems could not be deployed for managing coexistence between passive and active services, enabling, for example, bidirectional sharing (eg protected passive use of active bands and opportunistic active use of passive bands), and better protection of passive services from unwanted emissions from spectrally adjacent active services when and where needed. This talk will provide a high-level overview of how commercial spectrum sharing systems operate, and how certain features of those systems could be applied to passive/active co-existence. For example, in the SAS case, incumbents are protected by the establishment of Dynamic Protection Areas (DPAs) and associated DPA neighborhoods in which the contribution of all underlay transmitters to interference into incumbent services is considered. In some cases, DPAs are “activated” (ie the SAS is informed of the need to protect the DPA) by the use of a web-based portal, similar to a calendar utility, called an Informing Incumbent Capability (IIC). The DPA and IIC concepts could easily be extended, without modification, to protect ground-based passive systems, such as radio astronomy sites. With some modification, the concepts could be extended to protecting passive satellite sensors from ground-based interference, and ground-based passive systems from transmitters on satellites. These concepts, and other applications of commercial sharing systems to passive/active coexistence, will be discussed.