Geographical Identifier

Description

The Geographical Identifier (GI) is a 3GPP identifier that represents a specific geographic area or location. It is used across various 3GPP specifications to enable location-based functionalities, network optimization, and regulatory compliance. The GI can take different forms depending on the context, such as a cell identifier, tracking area code, or a more granular geographic coordinate system. In essence, it provides a common language for describing where something is or where a service should be delivered.

In the context of 3GPP, the GI is often associated with the identification of geographical areas for emergency services, lawful interception, and charging. For example, in emergency call handling, the GI helps route the call to the appropriate Public Safety Answering Point (PSAP) based on the caller's location. Similarly, for lawful interception, the GI can be used to determine the jurisdiction and legal requirements for intercepting communications. The GI also plays a role in network planning and optimization, where operators use geographical data to decide where to deploy cells, how to configure parameters, and how to manage mobility.

The GI is defined in various 3GPP specifications, including 23.842 (Study on Location Services (LCS) enhancements) and 37.462 (Study on enhancement for data collection for NR and EN-DC). These specifications detail how the GI is structured, how it is exchanged between network entities, and how it is used in different procedures. The GI can be represented in different formats, such as a string of characters, a set of coordinates, or a code that maps to a geographical area. The exact format depends on the use case and the interface over which it is transmitted.

One of the key aspects of the GI is its role in location services (LCS). In LCS, the GI is used to identify the location of a User Equipment (UE) for applications such as navigation, emergency services, and location-based advertising. The GI can be derived from various positioning methods, including GNSS, OTDOA, and E-CID. The network then uses this information to provide location-based services or to report the location to external clients. The GI ensures that location information is consistent and interpretable across different systems and vendors.

Another important aspect is the use of GI in network slicing and edge computing. In 5G, network slices can be tailored to specific geographic areas, and the GI helps in selecting the appropriate slice based on the UE's location. Similarly, for Multi-access Edge Computing (MEC), the GI can be used to determine which edge server should serve the UE, ensuring low latency and efficient resource usage. Overall, the GI is a fundamental identifier that bridges the gap between the physical world and the logical network, enabling a wide range of location-aware services and network optimizations.

Purpose & Motivation

The Geographical Identifier (GI) exists to provide a standardized way to reference geographic locations within 3GPP networks. Before its introduction, location information was often represented in proprietary or non-standard formats, leading to interoperability issues and limited support for location-based services. The GI solves this by defining a common identifier that can be understood by all network elements and external systems, facilitating seamless integration and service delivery.

The motivation for creating the GI was driven by regulatory requirements and the growing demand for location-based services. Regulators in many countries require operators to provide accurate location information for emergency calls, and the GI helps meet these requirements by providing a consistent means to identify the caller's location. Additionally, the commercial success of location-based services, such as navigation, local search, and targeted advertising, necessitated a standardized identifier that could be used across different networks and devices.

Furthermore, the GI supports network optimization and planning. By using a common geographical identifier, operators can analyze traffic patterns, optimize coverage, and plan capacity upgrades more effectively. It also enables new business models, such as location-based charging and location-aware network slicing. In summary, the GI was created to address the need for a unified, interoperable, and flexible geographical identifier that supports a wide range of applications and regulatory mandates.