Geolocation Database

The geolocation database is not an optional optimization tool; it is a legally required gatekeeper for unlicensed white space devices (WSDs). Regulatory bodies like the FCC (United States) and Ofcom (United Kingdom) mandate its use to prevent interference with protected incumbents, including broadcast television and wireless microphones. A WSD cannot transmit until it receives a positive authorization from a certified database administrator. This shifts the burden of interference protection from the device to a centralized, auditable infrastructure.

Unlike cognitive radio sensing, which is probabilistic, the database provides deterministic protection. It stores the precise geographic coordinates, antenna height, and transmission power of every protected incumbent. When a WSD queries the database with its location, the system applies strict propagation models (e.g., Longley-Rice) to calculate a conservative protection contour. The database then returns a list of available channels and the maximum permissible Effective Isotropic Radiated Power (EIRP) for each, ensuring the aggregate interference margin is never exceeded.

The database enforces a strict hierarchy of access rights, resolving contention before a device ever transmits. In the CBRS framework, this is a three-tier system:

• Incumbent Access (Tier 1): Absolute priority for federal radar and satellite operations.
• Priority Access License (Tier 2): Licensees who purchased rights via auction, guaranteed protection from lower tiers.
• General Authorized Access (Tier 3): Opportunistic, unlicensed use on any channel not reserved by a higher tier. The database dynamically suspends lower-tier grants when a higher-tier user activates.

A critical function is managing mobile or intermittent incumbents, such as naval radar. The database uses Dynamic Protection Areas (DPAs)—predefined geographic zones that can be activated on demand. When a federal incumbent triggers a DPA, the database immediately calculates the aggregate interference from all active secondary users within that zone. It then issues a spectrum handoff command, forcing all GAA and PAL devices to vacate the affected channels within a mandated timeframe (e.g., 300 seconds), ensuring zero harmful interference to the primary mission.

The physical implementation can be centralized or distributed, but the logical function remains the same. A centralized model, like a Spectrum Access System (SAS), aggregates all sensing data and makes global allocation decisions. A distributed model, like Automated Frequency Coordination (AFC) for 6 GHz, allows multiple competing database operators to calculate interference independently while sharing a common incumbent data set. Both architectures must synchronize state to prevent a rogue database from authorizing a device that would cause aggregate interference.

The database is a system of record with immutable legal liability. Every query, channel grant, and power authorization is logged with a timestamp and device identity, creating a complete audit trail. This data is used for post-hoc interference analysis and regulatory compliance verification. The database's integrity is paramount; a corrupted propagation model or stale incumbent record could result in a WSD causing harmful interference to a critical service, such as a wireless microphone at a live event or a radar system.

A three-tiered, automated frequency coordination system mandated by the FCC to dynamically manage and authorize spectrum sharing in the 3.5 GHz CBRS band. The SAS acts as the central policy enforcement point, using a geolocation database of incumbent federal and commercial users to calculate interference protection zones and grant transmission authorizations to lower-tier devices.

A centralized or distributed database-driven system that calculates and manages interference constraints to enable unlicensed devices to operate in spectrum bands occupied by incumbent fixed services, such as the 6 GHz band. Unlike a static geolocation database, the AFC performs real-time propagation modeling using terrain and clutter data to determine permissible power levels for standard-power access points.

A predefined geographic zone activated by a Spectrum Access System to protect a federal incumbent radar system from aggregate interference. When a naval radar is present, the SAS activates the DPA, requiring all CBRS devices within that geolocation database-defined boundary to cease transmission or reduce power within a mandated timeframe, typically 300 seconds for coastal DPAs.

A calculated safety buffer representing the total allowable interference from all secondary users at an incumbent receiver. The geolocation database uses propagation models to sum the predicted interference contributions from every authorized device within a protection contour, ensuring the cumulative signal power remains below the incumbent's operational threshold, typically defined as an I/N ratio of -6 dB.

A regulatory framework, primarily developed in Europe, that grants a limited number of licensees predictable, non-interfering access to a frequency band under a sharing agreement with an incumbent primary user. Unlike the dynamic geolocation database approach of CBRS, LSA relies on long-term, geographically defined licenses with pre-negotiated evacuation procedures, providing greater predictability for industrial private networks.

A multi-dimensional, real-time geospatial database that integrates sensor data, propagation models, and regulatory policies to provide a comprehensive map of electromagnetic activity. A REM extends the concept of a static geolocation database by incorporating live spectrum sensing inputs and machine learning predictions to create a dynamic, high-resolution picture of spectrum occupancy for proactive cognitive network management.