Privacy Exception List

Description

The Privacy Exception List is a 3GPP concept within the Location Services (LCS) privacy framework that consists of various types of privacy classes, such as operator-related and personal classes. Each privacy class defines a set of conditions and authorized LCS Clients that may locate a target User Equipment (UE). Certain types of classes may require an agreement between the service provider and the target UE, ensuring that location information is only disclosed under mutually agreed terms. The Privacy Exception List is a key element in balancing the need for location-based services with user privacy.

In the 3GPP architecture, the Privacy Exception List is managed by the LCS Client and the target UE's home network, and it is enforced by the Privacy Check Function (PCF) or equivalent entity in the core network. When an LCS Client requests location information for a target UE, the network performs a privacy check to determine whether the request is allowed based on the target UE's privacy profile and the applicable privacy classes in the Privacy Exception List. The list can include multiple privacy classes, each with its own set of rules and authorized clients. For example, an operator-related privacy class might allow the operator's own location-based services to locate the UE without explicit user consent, while a personal privacy class might require explicit user consent for each request.

The Privacy Exception List was introduced in 3GPP Release 99 (R99) and has been maintained across all subsequent releases up to Rel-19. The definition has evolved slightly over time, primarily in terminology: in R99, the target was referred to as the "target MS" (Mobile Station), while from Rel-4 onward, the term "target UE" (User Equipment) was adopted. Additionally, the wording of the definition has been refined over releases, with minor changes such as the addition or removal of articles (e.g., "a list" vs. "list") and punctuation. The core meaning of the Privacy Exception List—a list of privacy classes that define conditions for locating a target UE—has remained consistent.

Key components of the Privacy Exception List include the privacy classes, the LCS Clients, and the agreement mechanism. Privacy classes are categories of privacy settings that define which LCS Clients are allowed to locate the UE and under what conditions. LCS Clients are entities that request location information, such as emergency services, law enforcement, commercial location-based services, or the user's own applications. The agreement mechanism allows the service provider and the target UE to establish a contractual relationship that defines the conditions under which location information may be disclosed, particularly for privacy classes that require such an agreement.

The Privacy Exception List is closely related to other privacy and security concepts in 3GPP, such as the Privacy Class, the Privacy Check Function, and the LCS privacy requirements defined in TS 23.171 and TS 23.271. It is a critical enabler for location-based services, ensuring that user privacy is protected while allowing authorized clients to access location information when necessary. The concept is also relevant to regulatory requirements, such as emergency call location and lawful interception, where location information must be provided to authorized entities.

In summary, the Privacy Exception List is a fundamental building block of the 3GPP location services privacy framework. It provides a structured way to define which LCS Clients can locate a target UE, under what conditions, and with what level of user control. Its consistent presence across releases underscores its importance in balancing location-based service innovation with privacy protection.

Purpose & Motivation

The Privacy Exception List was created to provide a flexible and structured framework for managing privacy in location-based services. As LCS became more prevalent, it became clear that a one-size-fits-all approach to privacy would not work, as different types of LCS Clients and different usage scenarios require different levels of privacy protection. The Privacy Exception List allows for the definition of multiple privacy classes, each with its own rules and authorized clients, enabling a more granular and context-aware approach to privacy.

The concept also addresses the need for contractual agreements between service providers and users. Some privacy classes may require an agreement between the service provider and the target UE, ensuring that location information is only disclosed under mutually agreed terms. This is particularly important for commercial location-based services, where the user may need to consent to the use of their location data in exchange for the service. The Privacy Exception List thus provides a mechanism for users to control their location privacy while still enabling the delivery of location-based services.

Over time, the Privacy Exception List definition has evolved to use more inclusive terminology (target UE instead of target MS) and to refine the wording for clarity. Its continued presence in 3GPP specifications from R99 to Rel-19 demonstrates its enduring relevance and adaptability in the face of evolving privacy regulations and user expectations.