At the NEXES Core

The NEXES Research and Innovation Action aims to empower the integration of Internet-enabled technologies into emergency services in Europe and beyond.
What is the transformation required by public communications networks to support next generation emergency calls? How to ensure novel location and the exchange of critical information capabilities? In what way will interoperability with legacy emergency systems be guaranteed?

For the past year, NEXES partners have been dedicated to designing and implementing the core of next generation emergency services.

Abiding to an extensive set of system requirements that observe the users’ needs and expectations and comply with applicable regulations, recognised standards and best practices, the NEXES partners have been working hard to determine the adaptation works to be performed on public communications networks, to define an architecture for network and service convergence, to implement the critical and structural location function and to address the need for seamless interoperability.

Public communications networks are the basic infrastructure enabling the connection between citizens in distress and emergency responders. As mobile and fixed/landline communications networks evolve to empower next generation 112 emergency services, including the placing of emergency calls over IP networks, in support of total conversation capabilities and the use of 112 emergency applications as an over-the-top service, extensive adaptations to the access and the core network elements are required.

NEXES partners successfully designed and implemented a novel functional network architecture, representing the call flow of end-to-end next generation emergency calls, that is capable of handling IP-enabled emergency calls with a suitable end-to-end quality of service.

Specifically, mobile and fixed/landline communications networks were analysed and adapted from legacy circuit-switched towards packet-switched implementations, enabling emergency calls that use Voice-over-Long Term Evolution (VoLTE), Voice-over-WiFi (VoWiFi) and Over-The-Top (OTT) technologies. The development of an access network for the VoLTE and VoWiFi technologies and the integration of an IP Multimedia Subsystem (IMS) platform were key in establishing the new architecture for network and service convergence to handle next generation emergency calls, including those resorting to an OTT emergency application. Further, the migration activities ensured adequate support to the use of total conversation capabilities, the provision of accurate location information and the exchange of data concerning the user calling emergency services. Also relevant aspects concerning the routing to the most appropriate emergency service, prioritisation of emergency calls over regular calls and quality of service were duly addressed.

Overall, NEXES’s focus on universality (oriented to any public communications network), accessibility (support of total conversation capabilities) interoperability (coexistence of legacy systems and the new IP-based architecture) and innovation (OTT emergency applications over VoLTE and VoWiFi networks) highlights the opportunity and way forward to transform public communications networks to support next generation emergency services at a pan-European level.

Location in emergency calls is a critical function that serves two primary objectives: to determine the right emergency service to send the call to and to enabling the emergency responders on the field to find the citizen in need.
Next generation emergency services aim to benefit from advanced location capabilities that enable the attainment of those objectives with increased precision and accuracy and in less time.

NEXES partners are therefore concentrated in providing reliable and secure location functions, considering new devices and network access. Based on the state-of-the-art and architecturally appropriate specifications and standards, NEXES succeeds in providing advanced location capabilities by enabling access to location information from a wide range of new and evolving access technologies including 4G/LTE networks, WiFi Access Points, private enterprise networks and Global Navigation Satellite System positioning. Device-based location solutions can deliver highly accurate location information and WiFi location systems can provide accurate indoor positioning, having a very positive impact for callers requesting assistance and for emergency responders on-route.

Implementing a Location Information Server (LIS) functional in all-IP environments, associated with the access or an emergency application framework derived from the Pan-European Specifications for Emergency Applications (PESEA), is NEXES answer to provide better location information to emergency services, leading to improved call routing and the efficient dispatch of emergency responders. NEXES also provides a hybrid solution where an application location server, the GeoHub, may gather location information from a device application or subsystem and determine a route to an emergency gateway for pre-arranged areas. The NEXES solutions cover application-only architectures, OTT VoIP architectures, Total Conversation architectures, hybrid application voice-provider architectures and carrier IMS architectures. Related risks, issues and opportunities concerning anonymity, security and the identification of potential hoax or false calls are also addressed.

As a result, NEXES provides an extensive set of mechanisms and protocols for the acquisition, conveyance to, and updating of highly-accurate location information for emergency services that far exceed what is available in Europe today.

Indeed, the NEXES partners are quite aware that mainstream emergency services across Europe rely on fixed/landline and wireless circuit switched (legacy) originating networks and legacy emergency systems. As a consequence, NEXES has attentively considered the need to ensure interoperability, responsible for enabling legacy calls to reach next generation emergency services and next generation emergency calls to reach legacy emergency services.

The NEXES Gateways provide the necessary interworking functions for both signalling and media communication between the legacy and next generation systems to be implemented in any 3GPP network. Based on the recommendations by the European Emergency Number Association (EENA), NEXES Gateways are the Legacy Network Gateway (LNG), used to allow the interconnection of legacy access call origination with next generation emergency services, and the Legacy PSAP Gateway (LPG), used to allow interconnection of legacy emergency services with IP-based networks handling next generation emergency calls.

The NEXES-implemented LNG and LPG gateways are deployed and tested for integration with a fully IP and Session Initiation Protocol (SIP)-based IMS network, as defined by the European Telecommunications Standards Institute (ETSI), and with a legacy network with SS7 signalling protocol, defined in the International Telecommunication Union (ITU). In particular, NEXES implemented the SS7-to-SIP interworking function and the conversion of Time Division Multiplexing (TDM) voice coding to the IMS Real-Time Protocol (RTP) data and audio codecs to enable the connection with legacy networks. Also NEXES created the interconnection between the IMS-based mobile/fixed network with the legacy TDM emergency call taking and handling systems with no Internet-enabled technologies. Hence, NEXES assures emergency communications between legacy systems and next generation IP-based systems.

NEXES Gateways are thus mandatory for a smooth migration of emergency systems from legacy environments towards an all IP-environment. It is expected for their use to be merely temporary, as NEXES partners continue to work in the design and implementation of next generation emergency services and these become the new paradigm worldwide.

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