Emergency Call

Description

eCall is a pan-European emergency call service that automatically or manually connects a vehicle to the nearest Public Safety Answering Point (PSAP) in the event of a serious accident. It is designed to reduce the number of fatalities and the severity of injuries by ensuring that emergency services are notified immediately and receive critical data about the incident. The service is defined by 3GPP specifications, primarily TS 23.167, which outlines the architecture and procedures for emergency calls in the IP Multimedia Subsystem (IMS) and circuit-switched (CS) domains.

The core of eCall is the transmission of a Minimum Set of Data (MSD), which includes information such as the vehicle's location, direction of travel, vehicle identification number (VIN), and other relevant data. The MSD is sent from the In-Vehicle System (IVS) to the PSAP over the voice channel using an in-band modem (as specified in TS 26.267) or via an IMS data channel in later releases. The eCall can be initiated automatically by sensors (e.g., airbag deployment) or manually by pressing an SOS button. The call is routed to the PSAP with an emergency service indicator, allowing the PSAP to recognize it as an eCall and handle the MSD appropriately.

In the network, eCall leverages the existing emergency call framework. For CS domain, the eCall is established as an emergency call with a specific service category. For IMS, the eCall is established as an IMS emergency session with additional parameters to indicate eCall and to carry the MSD. The IVS attaches to the network and registers with IMS if available, or falls back to CS. The PSAP receives the MSD either in-band or via a data channel, depending on the capabilities and the release.

Key components include the IVS, which collects vehicle data and initiates the call; the PSAP, which receives the call and MSD; and the mobile network, which routes the call and ensures priority. The eCall service also supports callback from the PSAP to the vehicle for further communication. Security and privacy are important; the MSD is only transmitted to authorized PSAPs, and the system includes mechanisms to prevent misuse.

eCall has evolved over releases to support IMS-based eCall (eCall over IMS) and to improve reliability and data transmission. It is a critical component of intelligent transportation systems and is mandated in the European Union for new vehicles. 3GPP continues to enhance eCall to support new features like eCall only mode and improved MSD transmission.

Purpose & Motivation

eCall was created to address the need for faster and more accurate emergency response in road accidents. Before eCall, emergency calls from vehicles relied solely on voice communication, often resulting in delays and incomplete information. The service automates the process and transmits a standardized set of data, reducing response times and improving outcomes. It also helps emergency services locate accidents in remote areas and prepares them for the severity of the incident. The European Union's eSafety initiative drove the standardization and deployment of eCall, making it a regulatory requirement for new vehicles.