HIT‑GATE project’s goal is to develop a solution to communications interoperability between First-Responder networks, including those involving more than one nation. It will be reached by developing a novel technological solution that will interconnect all the existing communication systems via a dedicated node and ensure interoperability of all the desired systems without modifications of the handset devices and major communications infrastructure.
Therefore the main goal of the project is to develop a generic gateway that allows communications across networks currently used by First Responders in Europe. It is well known that, all over Europe, current First Responder (FR) networks use a large number of different and incompatible technologies therefore compromising efficient coordination of combined operations (such as cross-border or crisis management). It is also known that European organizations dealing with public-safety have invested in dedicated critical systems (to ensure high-availability and reliability). This includes dedicated networks of, among others, PMR (Professional Mobile Radio) and, more specifically, TETRA (TErrestrial Trunked RAdio) or TETRAPOL. Moreover, with the fast development of communications technologies, new capabilities and opportunities are being adopted and exploited by early-adopting First Responders, such as ad-hoc mesh broadband networks, able to provide and/or extend connectivity over affected areas (e.g., underground and destroyed area) and to deliver high data throughput (higher than 5 Mbps).
Therefore, to answer First Responders needs, HIT‑GATE will be developed to support a mix of technologies used today by organizations involved in Public-Safety, ranging from legacy-PMR, TETRA to next-generation networks. In this way, organizations may keep their existing systems and/or adopt novel technologies, since the proposed HIT‑GATE solution is future proof and ensures communications interoperability between the networks (limited, of course, to the limitations in capabilities of each network). HIT‑GATE will also enable communications across heterogeneous networks between First Responders during operations. By connecting HIT‑GATE to their networks, First Responders may continue to use their current receiver equipments, communications base-stations and communications infrastructures. The situation before and after HIT-GATE deployment is presented in Figure 1, that is, changing from isolated networks to connected networks.
Figure 1 HIT-GATE: before (left) and after (right) HIT-GATE
At both European and national/domestic levels, Public-Safety organizations have adopted a variety of systems, equipments and technology resulting in a plethora of networks that do not interoperate. Since current security and emergency activities frequently involve multi-national First Responders teams (e.g., natural crisis response and cross-border operations) it is crucial to provide an effective solution.
HIT‑GATE will successfully and seamlessly integrate heterogeneous Public Safety Communications (PSC) technologies – each comprising specific sets of protocols, services and characteristics – while ensuring mission critical requirements of PSC applications, including high-availability, dependability, security and, especially for the case of Emergency Forces / First-Responders, be rapidly deployable over mobile, highly-dynamic and unpredictable environments where existing infrastructures may be degraded and/or destroyed.
Interoperability, in fact, is a critical factor for European Public-Safety and Security related entities that deal with an environment that is complex, interconnected and interdependent. Not only local effects may require simultaneous and rapid intervention of different types of entities (such as police, fire brigade and medical entities) but may also cut across a national borders requiring combined intervention at the international level.
Lack of interoperability, on the other hand, results in the entities inability to work together and combine resources in an effective and efficient way. The likely outcomes, given current environment, are inefficient use of resources, increase the risks of injuring affected citizens and First Responders, and increase likelihood of failure.
The large variety of heterogeneous systems and equipments acquired and used by First-Responders belonging to European Public-Safety entities still present numerous issues concerning interoperability at its most basic level, i.e., the communication systems level.
We propose with HIT‑GATE a short-term solution to the problem of interoperability: to develop a gateway that interconnects the different networks and comprises all necessary translation protocols and services to allow cross-team communication.
The approach to achieve technical interoperability with HIT‑GATE is the following:
- HIT-GATE will provide technical interoperability between First Responders’ networks based on standard protocols to facilitate implementation and standardization. It supports First Responders’ networks with different technology (e.g., TETRA, TETRAPOL, PMR and WiMAX) and same technology (e.g., TETRA-TETRA).
- HIT-GATE will provide protocol and service translation across networks through common protocols and services defined by standards, depending on the compatibility of each network. That is, HIT-GATE may enable voice-calls across networks but will not provide digital data exchange between broadband networks and analog-PMR since the later does not support it.
- HIT-GATE will interconnect full-duplex and semi-duplex network, and will support group calls in full-duplex networks: PLMN, PSTN, ISDN, etc.
- The air-interface aspects of each network technology will not be changed and/or affected, including existing base-stations and infrastructures. That is, mobile radio terminals and base stations operate in the same way with or without HIT-GATE. This aspect reduces the scope of the problems and also ensures compatibility with existing equipments.
- HIT-GATE will enable dynamic plug-in/plug-out of networks and will include automatic-adaptive mechanisms to provide seamless access across networks. These properties are referred as ‘plug’n’play’ and ‘on-the-fly’. As a way to achieve these properties, the IP-protocol is used given its proven capability to connect a large number of heterogeneous devices.
- More than stand-alone equipment, HIT-GATE is an interoperability system which includes hardware and software developments. A HIT-GATE comprises adaptors that connect each First Responder’s network to an IP network. The adaptor translates the specific protocol of each technology to the IP protocol allowing a fast-setup and more flexible way to link multiple networks, unconstrained by limitations of using wires (e.g., mobility and range). Moreover, HIT-GATE instances may be connected with each other resulting in a network of HIT-GATE devices combining all sub-networks into a large-scale network of First Responders’ networks. This approach also provides the means to achieve internet-connectivity and, therefore, global access to central operational centres at remote locations.
HIT-GATE gateway will use open standards (e.g. SIP) that will be implemented in different layers – Figure 2.
Figure 2 Interworking of PPDR radio systems based on HIT-GATE gateway
HIT‑GATE gateway allows to operate in two scenarios: standalone and network.
Scenario 1: HIT-GATE with remote IP-adaptors (wired or wireless) connecting 4 heterogeneous networks
In this scenario, we conceptualized 4 networks of first responders: a TETRA network, a Broadband network (based on WiMAX), an analog-PMR network and a Coordination Command Centre network (IP-based). The networks are not interoperable. Each network is connected to an IP-adaptor (analog-PMR, TETRA or IP) that handles all necessary translation mechanisms to convert specific protocol into HIT-GATE standard form. HIT-GATE handles all necessary signalling and re-routing of data across networks.
Figure 3 Scenario 1: HIT-GATE with remote IP-adaptors
Scenario 2: Network of HIT-GATE gateways
A second scenario involves the creation of a large-scale network. More precisely, a network of first responders networks, by making use of the HIT-GATE ability to connect with other HIT-GATE gateways. This feature is presented in Figure 4. It can be used to deal with a large-scale multi-national situation.
Figure 4 Network of HIT-GATE gateways: a large scale network-of-networks