In today’s digital world, users of ‘first responder’ communication systems recognize the benefits that integrating Professional Mobile Radio (PMR) networks with new, advanced data services could bring to their task. 

Considering the current multimedia capabilities of both emergency and general-purpose mobile terminals, it is just a matter of time before police and/or firefighter units will expect to be able to transmit image-based vital information to central control rooms or to other emergency units, to assure quick and expert responses to critical incidents in real-time.

To satisfy the requirement of broadband emergency data services, plenty of effort has been devoted to improving data transmission capabilities for different PMR technologies. For example, TETRA Enhanced Data Service (TEDS), standardized within TETRA Release 2 at the end of 2005, is offered as a suitable medium for advanced security services such as video surveillance, extensive image sharing and positioning. 

In May 2010, the first large-scale TEDS pilot was launched and delivered to a customer’s network (Virve, Finland’s nationwide TETRA network).

However, TEDS technology is being left behind by the growing requirements of new security applications. The need to upgrade TETRA to broadband has become inescapable. In fact, because the lack of wider channels for existing TETRA systems will result in 50–100 kbit/s data services (far from the theoretical maximum of 540 kbit/s), the first wave of incoming TEDS will not meet the broadband requirement, despite its potential capabilities. Thus, discussion in the TETRA + Critical Communications Association (TCCA) has lately focused upon which kind of broadband solution(s) should be adopted: the integration of other broadband technologies or the evolution of TEDS technology.

At the same time, commercial wireless technologies are evolving from traditional GSM/GPRS/UMTS services towards more advanced wideband solutions such as WiMAX or LTE, to support wider coverage and higher data rates (up to 50–100 Mbit/s).

In an all-IP world

The future of mobile communications seems to be directed towards an all-IP world, which has raised a considerable amount of discussion regarding the provision of multimedia services. During 2010, the GSM Association (GSMA) adopted the IP Multimedia Subsystem (IMS) as the key driver technology to support voice services over LTE. Thus IMS can be considered as the dominant candidate for the provision and management of multimedia services in future 4G networks.

On the other hand, in order to incorporate new, advanced multimedia services to first-responder communication systems, it is essential to ensure that the critical communications infrastructure is not fully saturated. In such a scenario, the convergence of both high-capacity, general purpose mobile systems and PMR systems is emerging as a relevant topic.

Several user organizations have already combined the two technologies, providing their professionals with dual terminals, although a distinction is made in use: PMR is used for critical transmissions and the general-purpose mobile network for non-critical transmissions. A converged scenario would enable those professionals to make the most of both worlds, while assuring an accurate use of critical resources.

Project GERYON 

GERYON is an EU-financed project involving seven organizations across Europe – three academic institutions and four industrial partners. Its aim is to explore and develop a next-generation, technology-independent interoperability system of emergency networks and services based on IMS, seizing the existing window of opportunity due to the convergence of the IMS (a predominant enabler for future multimedia networks) and the imminent deployment of commercial LTE networks. 

GERYON proposes an innovative emergency inter-networking system which is capable of connecting first responders’ existing communication systems and enabling the integration of these systems with next-generation mobile networks by defining technology-independent standardized interfaces and autonomous configuration and adaptation techniques under the umbrella of IMS. In this way, GERYON will unify common technical and operational logic of first responders’ communication networks in a manner independent of technology.

By providing a neutral interconnection interface, this unification will offload interconnection gateways from duplicated technology-dependent details. The proposed system will ensure seamless operation regardless of the access technology and will take advantage of coverage and responsiveness of both existing PMR networks and the broadband data services of 4G networks.

Enhanced services

GERYON will demonstrate both classical (e.g. push-to-talk, group call and pre-emptive calls) and enhanced emergency services (e.g. multimedia streaming and data services) over a cross-frontier testbed. Furthermore, its capability for including general-purpose IMS terminals and GERYON-enhanced ones will allow easy and secure access to first responder networks by different groups of vulnerable citizens – such as elderly people, people with special needs and threatened people. They will take advantage of GERYON enhanced services such as the Red Button over general purpose devices.
(中國(guó)集群通信網(wǎng) | 責(zé)任編輯：陳曉亮)