Emergency Call Standards (911 and 112 Services)

In IP protocol networks, it has been agreed, for emergency calls, to set up special infrastructures so that the public can transmit text, images, videos and data from the terminal used to the 9-1- 1 in North America and 112 Centers in Europe.

However, the adoption of these evolved technologies in emergency communications between citizens and public authorities faces a series of barriers, including the lack of harmonized and interoperable solutions. Different initiatives worldwide are addressing the need for specifying a stable IP-based next generation emergency communications framework.

The National Emergency Number Association (NENA) initiated development activities in 2003 and in March 2016, a public consultation was opened in the United States to define the services that should be offered. In 2015, the FCC launched a national working group.

The European Telecommunications Standards Institute (ETSI) Special Committee (SC) on Emergency Communications (EMTEL) has been specifically focused on emergency communications, including emergency call services, caller location enhanced emergency services, and public safety communication systems.

It is estimated that approximately 320 million emergency calls are made every year in the European Union. At the same time, multimedia applications and voice over IP (VoIP)-based devices have become commonplace, and citizens use them to conveniently communicate, sending and receiving multi-modal information. Among several standardized and proprietary over-the-top (OTT) VoIP solutions available today, voice over LTE (VoLTE) seems to be playing a significant role in the near future, as predominant access to emergency services from fourth generation (4G) broadband mobile networks. In fact, more than 60 percent of emergency calls are already from mobile devices in the EU.

Nevertheless, the existing legacy emergency services infrastructure (circuit switched telephony for 112 telephone calls, not data) is not designed in a way that enables interaction with enhanced services, or current and future communications and operational requirements to be met.


NG911/NG112 systems are designed to close the gap between the quickly evolving technologies (fixed and mobile IP-based communications) and the more conservative approaches required by the emergency communications industry (including public administrations).

Tin North America, the NG9-1-1 vision is based on a specific application functionality on an ESInet (Emergency Services IP Backbone Network) to provide voice, video, Text and data to PSAP, a “Public Safety Answering Point”. The protocol used to provide these “calls” will be Session Initiation Protocol (SIP), or IP Multimedia Subsystem (IMS, which incorporates SIP). The functional and interface standards developed by NENA describe general SIP and IMS architectures that allow 9-1-1 managers flexibility in developing an infrastructure to support the intended functionality of the NG9-1-1.

In the current 9-1-1 environment introduced in the 1960s, the public can only dial emergency calls and teleprinter calls (for deaf or hard of hearing people). Only the minimum data is provided with these calls, such as automatic identification of numbers, subscriber name and automatic location identification, where available.
Progress in the implementation of NG communication services based on these specifications is slow. Many technical challenges will have to be resolved, as will many political and financial issues.

Progress in the implementation of NG communication services based on these specifications is slow. Many technical challenges will have to be resolved, as will many political and financial issues.

The planning and pre-deployment of NG911 in Illinois rural area in the United States shows how collaboration between industry, academia and standards and regulatory bodies was used to modernize emergency services, providing a template for similar efforts expected in the future.


In recent years, a large number of “SOS” and “Help” applications have been created. Almost all European emergency services have been contacted by developers who wanted to send data and establish a voice connection directly to 112. Different solutions have been built on heterogeneous technologies that are not generally interoperable. This may explain why some public authorities have already developed their own official applications that can only be used by citizens living in a certain geographic area and may not work properly if they are used outside the boundaries of a certain PSAP.

Two Classes of Standard

The use of standardized or industry-adopted technologies may help to overcome this heterogeneity in emergency apps and OTT VoIP services. Different technologies can be identified as prevailing candidate solutions, including the use of WebRTC or the mobile industry supported Rich Communications Suite (RCS). However, none of the solutions have really gained the required wide support in the emergency communications world.

In the future, the public will be able to launch voice, text or video emergency calls from any communication device via networks using the Internet protocol. The PSAP of tomorrow will also be able to receive data from personal security devices such as Advanced Automatic Collision Notification systems, medical alert systems, and sensors of various types. The new infrastructure envisaged by Project NG9-1-1 will support the national interconnection of 9-1-1 services, as well as the transfer of emergency calls to other PSAPs, including related data. The PSAP should be able to issue emergency alerts to wireless devices in an area through voice or text messages, and to road alert systems.

The Next Generation 911 (NG911) technology will be enriched with the challenges and solutions implemented by providing emergency NG communications to communities, as well as validation and new services such as Emergency Services In vehicles.

In summary, it can be observed that the major standardization efforts concerning next generation citizen-to-PSAP communications (from ETSI, IETF, etc.) are based on IP-based networks and SIP communications, with different flavors and architectural specifications.

It must be noted that the scopes of the EENA NG112 and ETSI NTECH working groups are different. ETSI NTECH is focused on the standardization of a general solution for emergency caller location acquisition and transport, which is valid for heterogeneous deployment alternatives including current and next generation communications systems. While NENA and EENA architectures are based on the concept of a unified ESInet with a common SIP-based signaling suite, ETSI NTECH develops its solution taking into account the complex deployment context where each European PSAP may be served by one or more national network operators. Due to national regulatory requirements, network-provided location information is used, and the voice service provider (VSP) gets the routing information from the location server (LS) based on a new extension to HTIP-enabled location delivery (HELD).

European Test Bed

In March 2016, ETSI and EENA co-organized the first emergency communications interoperability test in Europe. Thirteen vendors participated in the tests, providing different FEs including different types of user equipments (UEs) and PSAPs, mobile apps, IP/IMS/UC/PSTN access networks and different ESInet elements such as BCF, LIS, ESRP, and ECRF. In addition to NG112 industry partners, seven external international observers attended the event in order to get first-hand experience from the current situation of the NG112 developments.


Mobile broadband technologies are quickly evolving, adding the possibility for end users to adopt enhanced multi-modal communications in their daily communications. However, the use of these novel multimedia capabilities is hardly incorporated into the overall management of emergency services due to the lack of standardized solutions.

The EENA NG112 LTD solution has now been passed to a first testing phase, where different interoperability events will be organized under the auspices of ETSI and with the support of the EC.

In Europe, the European Emergency Number Association released the NG112 Long Term Definition document, which is targeted to close the gap between the evolved needs of the end users and the public authorities in emergency management.

The EENA NG112 LTD solution has now passed to a first testing phase, where different interoperability events will be organized under the auspices of ETSI and with the support of the EC. As a result of these interoperability events, it is expected to validate the maturity of the architectural solution and the associated commercial products. Additionally, these events will provide valuable feedback to re-design and fine-tune the NG112 architecture.

As a step toward the adoption of the NG112 LTD document as a European-wide solution, and after the experimental validation of the proposal, it is expected that the document will be submitted for consideration as an ETSI standard. In this sense, the NG112 LTD solution needs to fulfill the specifications related to caller location procedures provided by the ETSI NTECH working group, with special focus on the ESInet-based deployment. See also www.comsoc.org/ [IEEE Communications Magazine, vol 55/1, January 2017]

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