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Enhanced Communications in Emergencies by Creating and Exploiting Synergies in Composite Radio Systems

Final Report Summary - HELP (Enhanced Communications in Emergencies by Creating and Exploiting Synergies in Composite Radio Systems)

Executive Summary:
Project HELP has defined a comprehensive solution framework for the provisioning of Public Protection and Disaster Relief (PPDR) communications based on the exploitation of network sharing and spectrum sharing principles between Public Mobile Networks (PMNs) and Public Safety Networks (PSNs).
At an initial stage, Project HELP characterised the relevant operational scenarios and derived user requirements on the envisioned solution framework. Operational scenarios and user requirements were prepared and validated through the establishment of a User Advisory Board (UAB) with a range of public safety members drawn from the emergency services of Europe. Next step was to develop the system technical requirements, which were also validated by the UAB. In parallel, a feasibility study of network and spectrum sharing solutions was addressed. This work established the technical background needed for the elaboration of the system concept and the subsequent development of the system design and management framework. With all these foundations, the definition of the Project HELP system concept was formulated, which was realised through the development of a high level functional model of the overall solution framework. A preliminary view of the system concept was presented and discussed in a first Workshop organised by Project HELP, which was held in Ispra (Italy) on 10th and 11th October 2011. The mobile network operators’ representatives enrolled in the Project HELP Operator Advisory Board (OAB) also expressed their views and opinions during the Workshop. After a further elaboration of the different solution approaches, the final proposed Project HELP solution was again discussed and consolidated with UAB and OAB members in the second Project HELP Workshop, which was held on 17th April 2012 in Manchester, UK. Techno-economical considerations and conclusions raised from the study conducted within Project HELP have also constituted a valuable input to the elaboration of the final Project HELP solution.
Key pillars of the proposed Project HELP solution are the following:
• The system architecture is based on the utilization of Long Term Evolution (LTE) technology for mobile broadband PPDR.
• The proposed solution enables the delivery of PPDR services through both dedicated PSNs and commercial PMNs.
• The system architecture enables PPDR users to have a tight control of service provisioning and network resources.
• Interoperability with legacy PSNs is supported (e.g. TETRA/TETRAPOL).
• The system architecture, which provides the key capabilities related to user management and service provisioning across different networks, is expansible to support advanced functionalities such as dynamic spectrum management, dynamic capacity and coverage management and situational awareness.
• Spectrum for PPDR communications is managed according to a hybrid solution based on the joint exploitation of both dedicated and shared spectrum.
Project HELP system architecture solution could be readily implementable in the short/medium term as LTE equipment market is a reality that is rapidly progressing. Further progress still expected on technologies, standards and regulation for a full exploitation of all the capabilities considered within the proposed solution framework is discussed in the document.

Project Context and Objectives:
Wireless communications technologies play an irreplaceable role in emergency and disaster relief situations where appropriate communications between first responders, authorities and citizens is crucial. It is generally acknowledged that existing wireless communication networks frequently fall short of meeting users’ needs and consequently cannot properly support the management of these critical situations. Even though the Public Safety (PS) community's technological needs have been understood for a long time [1][2], the capabilities of current PS communications systems (e.g. Private Mobile Radio, PMR) are still lagging far behind some of the capabilities available in commercial mobile networks [3]. Some of the major limitations of PS communications systems in emergency and disaster relief scenarios are:
• Lack of interoperability. The diversity of technologies used by PPDR organisations and the utilisation of a number of separately managed PS communications networks often inhibit the cooperation between different agencies. Moreover, even when using the same technology, the networks can’t interoperate and the constraints on the security level constitute an additional barrier.
• Lack of network capacity in emergency scenarios. Whilst the PMR network operators have optimised the use of their communication systems in their day-to-day service, the situation changes dramatically when an emergency causes additional stress for the system (and the operators). Emergency scenarios usually lead to exceptionally high traffic loads, that a single (e.g. PMR) wireless communication system may not be able to support. This situation can be worsened in scenarios with limited radio coverage (e.g. a traffic crash in a tunnel) or when parts of the communications infrastructure are damaged in the incident area. Furthermore, the locations where emergency and disaster relief operations occur are unpredictable and the availability of communications facilities itself is not guaranteed in the incident area.
• Lack of support for broadband data rates. The evolution of PPDR operations has created the need for applications where large amounts of data are exchanged between first responders or between the tactical front line responders and multi levels of a hierarchical command structure. Data-intensive multimedia applications have a great potential to improve the efficiency of disaster recovery operations (e.g. real-time access to critical data such as high resolution maps or floor plans, on-field live video transmission from cameras on helmets to a central unit, telemedicine, etc.).
Besides, typically constrained budgets of the PPDR community are also challenging the technological evolution in the PPDR domain. In this framework, the deployment and operation of multiple and costly permanent network infrastructures to deliver increasingly data-intensive PPDR applications is no longer considered to be a cost-effective approach, at the same time that hinders interoperability between the different PPDR agencies. In addition, the allocation of enough dedicated spectrum for PPDR radio communications is a challenging issue for public administrations: suitable spectrum bands needed to build cost-effective PS networks with broadband capabilities are the same highly valued bands demanded by the market to provide commercial wireless communications.
Based on these observations, it is evident that more efficient and effective advanced wireless communication solutions to support PPDR communications than today’s systems are needed. Whilst this generic challenge has always been present in the PS domain, recent political and operational evolutions in Europe are calling for major attention to this critical aspect. Political evolution is pushing for an increased collaboration among PS organisations of various nations of Europe. This has made evident the need for harmonised procedures, technologies and spectrum allocation for PPDR communications [4]. In this context, Project HELP advocates that the complex requirements of modern emergency and disaster relief communications can only be addressed by a solution framework targeted to create and exploit synergies of composite radio systems encompassing commercial and PMR networking technologies. The envisioned solution framework consists of significantly strengthening the role and commitment of commercial wireless infrastructures in the provision of public safety communications, especially in the case of aftermath crisis scenarios where the exceptional traffic demand can exceed the capacity and coverage provided by any single infrastructure. The foundations for the development of such a solution framework stand on the exploitation of sharing principles applied to the two key assets needed to support PPDR communications: the wireless network infrastructure and the associated radio spectrum. These two major pillars will be referred in the following as network sharing and spectrum sharing. The introduction of sharing principles for the delivery of PPDR services is expected to provide:
• Enhanced interoperability. The adoption of network and spectrum sharing principles is tightly coupled with removing interoperability barriers since interoperable technologies will be definitively needed to be able to share communications resources. Hence, enabling access to PPDR services through commercial wireless networks requires the adoption of compatible technologies in the radio interface as well as interworking solutions on the infrastructure side between commercial and PS networks. Likewise, sharing of dedicated PS networks among different PPDR agencies also requires interoperability issues to be solved within PMR technologies and PS networks’ context.
• Increased PPDR communications aggregate capacity and coverage in emergency scenarios. Due to the unpredictable nature of an incident in time, place and scale, the achievement of the highest possible capacity and the best possible coverage for PPDR services by using (sharing) all available communications facilities in the affected area (e.g. dedicated PS or commercial networks) is essential. Likewise, enabling (sharing) additional spectrum to support PPDR communications in the crisis scenario will also contribute to fulfil capacity/coverage needs in a given incident response.
• Increased data rates. In addition to the adoption of a broadband radio technology (e.g. Long Term Evolution - LTE) for PPDR communications, the achievement of high-speed data rates is also facilitated by shorter distances to network cell sites from incident locations and increased spectrum availability. Sharing approaches enabling access to more radio spectrum and to various wireless network infrastructures will, therefore, facilitate broadband operation.
The adoption of sharing principles will also increase utilisation efficiency of the wireless networks and spectrum assets used for the provisioning of PPDR services. Sharing principles will also contribute to spread ownership and operation costs of those communications assets among the different involved public government bodies as well as considering the implication of the private sector (e.g. commercial mobile network operators, utilities, etc.). The adoption of network and spectrum sharing principles should foster at a large extent the creation of synergies with market forces in order to e.g. capitalize on infrastructure sharing opportunities for the PPDR community as well as facilitate PPDR communications to keep pace with the fast technology evolution associated with the market domain and prevent PPDR infrastructure from lagging again behind commercial solutions. In particular, Project HELP pursues two major objectives:

I. To define a solution framework –based on “network sharing” and “spectrum sharing” principles- for public safety communications able to exploit and properly coordinate available wireless communications systems in an incident zone, including those whose main usage is not for public safety communications (e.g. cellular, broadcast, etc.).
II. To identify the required operational and management features and related functionalities of the established communications framework to achieve a synergic and holistic operation of the diverse wireless infrastructures.

In turn, the detailed objectives of Project HELP are stated as follows:
• Objective 1: To identify operational user requirements, scenarios and overall system requirements. Project HELP will identify and describe the most critical public safety operational scenarios with respect to the need for communication resources as well as challenging radio communication environment. The scenarios will be created jointly with public safety users from diverse emergency service organisations and from as many countries across Europe as possible. Envisioned scenarios cover large-scale incidents that would require a coordinated response from crisis managers and first responders from different agencies across Europe and with resources from all levels of government. Based on the description of the operational scenarios and user requirements, the system requirements for a flexible and secure composite wireless communications solution will be defined.
• Objective 2: To define a solution framework (system concept) for the provision of public safety communications over diverse wireless infrastructures. The system concept definition will be addressed by conducting a feasibility study that will cover aspects such as:
- Defining the role that each system should take attending to its capabilities and the corresponding techniques and solutions that should be implemented to enable efficient interoperation among all involved systems.
- Determining required features and functionalities, changes/extensions that will enable the use of commercial systems, based on, e.g. 3GPP and IEEE 802.x standards, for public safety communications in emergency and disaster relief operations. In particular, capabilities for network sharing and traffic prioritisation will be considered. Furthermore, the potential support of specialised PMR-like services over mainstream cellular technologies (e.g. group services) will also be covered. Finally, the support of public networks may not be limited to emergency situations, e.g. public safety users could also use these networks during routine operation.
- Determining internetworking solutions between public safety and commercial communication systems. In particular, interworking solutions between PMR networks (e.g. legacy TETRA networks, more advanced solutions conceived around advanced packet switching networks) and public wireless access networks (e.g. 3GPP networks, WiMAX, 802.11-based networks) will be addressed so that public safety communications services can be provided over the two types of networks in an incident area. As well, interoperability between diverse PMR technologies used in the distressed area will be considered. These mechanism should cover technical issues, related to mobility, security and handling of access rights to the involved wireless systems.
- Analysing the feasibility of introducing specialised IP-based service platforms for public safety communications. In this regard, IMS-based platforms for emergency and first responder networks supporting most of the functionality required by emergency networks can be envisioned so that these platforms can be reachable from the diverse wireless networks. These platforms can support, e.g. specific directory and presence services allowing the crisis management authorities to contact the relevant emergency resources where ever they are located and what ever communication network they are using.
- Determining new spectrum usage models to enhance communications in emergency scenarios by means of proper spectrum management mechanisms among PMR and commercial radio technologies, including the operation of fast deployable communication systems. In this context, innovative spectrum usage models enabled by the development of dynamic spectrum access technologies like cognitive radio will be considered. Advanced forms of exclusive spectrum usage rights (e.g. governed by a spectrum broker) together with spectrum commons and opportunistic spectrum access (e.g. opportunistic usage of white space (WS) in the UHF TV bands) will be considered for the overall solution, which may require the combination of several approaches together with dynamic network planning.
- Ascertaining the qualitative benefits of the availability of additional communications resources from several heterogeneous systems for the communication capacity of the public safety and emergency services.
• Objective 3: To define a framework for the management of the composite emergency network. A feasibility study for the realisation of a flexible radio network operation and management framework will be addressed considering different management levels and principles:
- Inter-system management. Mechanisms to determine communication needs and capacity requirements of the affected zone attending to established operational crisis management requirements. Determination of the operational configuration and capacity planning requirements of each network within the composite emergency system have to be derived attending to the capabilities supported by each available network.
- Intra-system network management. A range of management mechanism will be analysed (e.g. dynamic network planning, radio resource management algorithms, flexible spectrum management strategies) in order to cope with the particular role and communication requirements of each involved system while enabling the synergic operation of the composite radio networks. The proposed solutions will consider that the drivers for these mechanisms in emergency scenarios can be quite different than those considered in normal network operation (e.g. reliability can be a crucial driver instead of improving system capacity, user/services prioritisation can also be a key issue). Specific mechanisms to cope with agile infrastructure-based deployment (e.g. portable base stations) will also be considered.
- Terminal equipment management. Different operational modes (e.g. infrastructure-based, direct) will be considered along with their corresponding management mechanisms. Capabilities and management criteria enabling opportunistic spectrum access for terminals operating in direct/ad-hoc modes will be of particular relevance.
- The conception of the overall management framework will consider self-management, autonomic management and cognitive-management as potential driving factors. Furthermore, concepts such as “virtual networks for public safety communications”, where the creation of virtual logical self-organising network on top of existing network technologies is envisioned in order to reduce complexity and facilitate immediate availability, will be further elaborated.
• Objective 4: To conduct a techno-economic analysis. The economic impact that the novel technical solutions proposed in Project HELP may have on the involved stakeholders (e.g. administrations, network operators) will be investigated. Recommendations regarding business models as well as desirable standardisation and regulatory actions will be developed. In particular, some aspects that will be considered are:
- Cost savings by sharing existing commercial networks instead of deploying and operating private networks.
- Leveraging technology investments targeted at a user population that is orders of magnitude larger than the PMR market.
- Enhanced network features which may appeal attractive (high ARPU, low churn) to new user groups (professional users).
- Shared access to otherwise unavailable spectrum.
- Analysing the feasibility of adapting commercial networks to public safety needs in case of emergencies in terms of investigating measures to offset possible economic impacts on the network operator.
• Objective 5: To establish a consolidated basis and roadmap for the realisation of the envisioned solution framework. Project HELP dissemination plan is strongly committed towards the achievement of a qualified wide awareness and support of relevant end users, European industry and research community so that the resulting solution framework will firmly constitute a solid basis and establish a clear roadmap for a future realization of better public safety communications. Project HELP will establish links with other relevant bodies or organisations to reach expected critical mass and establish a consolidated basis for the envisioned emergency composite network system:
- A User Advisory Board (UAB) and an Operator Advisory Board (OAB) will be established to validate system requirements and the envisioned system concept and solution framework respectively.
- Two Workshops will be organised to provide an independent validation process and dissemination of the projects objectives and developments.
- Project HELP will establish links with regulatory and standardisation organisations, which are working on the evolution of public safety communications. This includes ETSI TC TETRA, ETSI TC RRS, ETSI TC EMTEL, CEPT, Project MESA, the relevant agencies and DGs of the European Commission and FRONTEX. Liaison with the UN responsible for the Tampere Agreement on Public Safety Communications is also envisaged
- Links will be established with ongoing projects in the same area like Public Safety Communication Europe (PSC-E), EULER and others.

Project Results:
Project HELP has defined a comprehensive solution framework for the provisioning of PPDR communications based on the exploitation of network sharing and spectrum sharing principles between Public Mobile Networks (PMNs) and Public Safety Networks (PSNs).
At an initial stage, Project HELP characterised the relevant operational scenarios and derived user requirements on the envisioned solution framework. Operational scenarios and user requirements were prepared and validated through the establishment of a User Advisory Board (UAB) with a range of public safety members drawn from the emergency services of Europe. Next step was to develop the system technical requirements focused on those aspects which are relevant for the context of the Project HELP. The system requirements, which were also validated by the UAB, are classified in two main categories: functional requirements, which describe what the system should provide to support specific functions; and non-functional requirements, which are transversal to the functions. Functional requirements are grouped in three sub-categories: prioritisation; interoperability and interworking; and resource management. Non-functional sub-categories include availability, security and usability. In parallel to the development of the operational scenario and requirements, a feasibility study of network and spectrum sharing solutions was started. This work established the technical background needed for the elaboration of the system concept and the subsequent development of the system design and management framework. The scope of the analysis included: (1) Definition of the concepts network sharing and spectrum sharing, (2) Elaboration of a comprehensive taxonomy of network and spectrum sharing cases, (3) Determination of the key technical challenges behind sharing cases and (4) Feasibility analysis of potential network and spectrum sharing solution enablers and initiatives, covering the current status of these potential solution enablers and initiatives as well as main trends, evolutions or developments under way.
With all these foundations, the next step was the definition of the Project HELP system concept, which was realised through the development of a high level functional model of the overall solution framework. A preliminary view of the system concept was presented and discussed in the first Workshop organised by Project HELP, which was held at the facilities of the Joint Research Centre of the European Commission in Ispra (Italy) on the 10th and 11th October 2011. The Workshop provided important feedback to Project HELP on the needs of PPDR organizations, the evolution of PS communications technologies and the feasibility of network and spectrum sharing solutions investigated in Project HELP. In addition to the preliminary view of the system concept, first potential design approaches for the proposed functional blocks were presented at this first Project HELP Workshop. The mobile network operators’ representatives enrolled in the Project HELP Operator Advisory Board (OAB) also expressed their views and opinions during the Workshop.
After a further elaboration of the different solution approaches, the final proposed Project HELP solution was again discussed and consolidated with UAB and OAB members in the second Project HELP Workshop, which was held on 17th April 2012 in Manchester, UK. Techno-economical considerations and conclusions raised from the study conducted within Project HELP have also constituted a valuable input to the elaboration of the final Project HELP solution.
The remainder of this section is organised as follows. Next subsection 1 provides a description of the operational scenario and resulting user requirements and focus areas that form the basis on which the solution is formulated. Then, subsection 2 covers the description of the proposed solution encompassing (1) its high level functional model, (2) the system design pillars driving the development of the Project HELP solution, (3) the Project HELP system architecture in terms of functionalities, network components and related interfaces, (4) the support of advanced functionalities concerning dynamic spectrum management, dynamic capacity and coverage management and situational awareness, (5) required further progress still expected on technologies, standards and regulation for a full exploitation of all the capabilities considered within the proposed solution framework, and (6) the main considerations arisen from the techno-economic analysis on the impact that the technical solutions proposed in the Project HELP may have on the involved stakeholders.

1.- Operational scenario
For the purposes of emergency services operating methods and requirements, it is reasonable to suggest that, to a certain extent at least, ‘an incident is an incident’: recognising that, whilst there will be issues of scalability and certain incident-specific criteria (such as cross-border communication), it is both unnecessary and unrealistic to manufacture either large numbers of small-scale scenarios or one which is based on a colossal, continent-wide scale. It is far better to create a feasible, realistic incident which contains the relevant operational problems – in effect, a realistic, sequential series of events, from which a scalable technical solution can be developed. This approach has the added benefit of being infinitely more attractive to potential users of the system in the future. The scenario developed in Project HELP concentrates on the early stages of a major incident, rather than the incident as a whole. The scenario describes an incident which could happen in many locations and which, although having relatively small beginnings, expands considerably over a relatively short timeline. The reasoning behind this is that if a solution can be delivered where it matters, when operational resources are limited and operational intelligence regarding the incident is still limited, then that solution can be extended into the longer term as the incident stabilises and ultimately, the affected area returns to a state of normality.
The scenario creates a hypothetical location, incident circumstances and response: however, the resources available at such a location are realistic as are the varied communication networks available. A sketch map of the area and the emergency service resources available is shown at Figure 1.

1.1.- Description of the area and demographics
The location of this incident is on the coast and extending into a largely rural community of some 10 km2. A coastal town of some 5,000 inhabitants is divided by the mouth of a river. The town contains rural police, ambulance and fire stations all with limited capacity. In all cases, the services provide cover for the town itself and for pre-defined geographical areas beyond it. In the event of an incident outside this area, it is possible that some of these resources may be called to assist elsewhere. The police service provides a 24-hour presence with two patrol vehicles and usually no more than 4 officers available at any one time. The fire service for the town is ‘retained’ (part-time), consisting of crews who are in other forms of full-time work and are called when required for fire and rescue duties by SMS. The ambulance service for the area has one rapid-response vehicle. This is staffed by a skilled medical paramedic who can use specialist equipment such as defibrillators and administer controlled drugs. The vehicle is equipped accordingly.

1.2.- Description of the available infrastructures
The police and ambulance services each use their own area of a common, dedicated communications system for voice and data transmission (herein referred to as the Public Safety Network -PSN-). In addition, they may use the commercial cellular telephone network in the area (herein referred as Public Mobile Network – PMN).
A PSN base station is located on the roof of the police station. As the area is mainly rural in character, the PSN has limited capacity in comparison to an urban area. The fire services use a mixture of analogue and digital radio equipment on VHF frequencies. The nearest VHF base station used by the fire service is located on top of a mountain some 50 km distant.
The local police, ambulance and fire facilities are connected to their control centres (which are not necessarily co-terminus with their headquarters and are outside the incident area) by the PSN (police and ambulance only), VHF analogue / digital system (fire services) internal secure computer networks (usually hard-wired or microwave), landline telephone and fax. Two PMNs in the area host a number of commercial telecoms providers to provide voice and data communications.

1.3.- Description of the incident
At some stage during normal working hours on a weekday, a train carrying Liquid Petroleum Gas (LPG) is derailed close to the town. Two of the wagons are ruptured allowing LPG to leak out. This gathers around nearby houses. After some minutes an explosion occurs, followed by a widespread fire. This fire attacks a building which contains paints and thinning chemicals in large quantities.
Initial calls are made to the emergency services from members of the public over the PMNs and from nearby premises over the land-line telephone system. Local ‘retained’ fire services are called out via SMS and the area police and ambulance services are tasked to attend.
Information on the status and extent of the incident is being passed by the first resource at the scene via radio to their control centre and from there by telephone and data transfer to the other control centres, from where it is relayed back out to the respective resources at or attending the scene.
The local retained fire service arrives on the scene. They also request out-of-area support from their own service: the fire is beyond their capacity to bring under control. Dense smoke and fumes are rising from the fire and drifting inland.
As the local ambulance service arrives at scene, they also request additional support via their own communications channels as there is an unknown number of casualties inside the building, compounded by the fact that the fire is spreading and putting further lives at risk.
The authorities, via their vehicle-borne public address systems, advise residents to stay indoors and close doors and windows to keep fumes out. Outbound traffic evacuating the scene by road results in a road accident as a result of which, a telegraph pole is demolished and land-line communications to the town are severed. All communication, both public and emergency services is now being conducted over PMN and PSN.
Emergency service support personnel and equipment are moving into the area to be directed by operational-level commanders. Tactical-level command posts are established as close to the affected area as it is safe to do. Communications links between the different command levels must be established and maintained. These mobile control centres should have direct voice/data communications links back to their respective control centres. The PSN base station on the roof of the building has been destroyed by the LPG explosion.

1.4.- Impact on communications
This incident will require not only the existing local emergency services to respond and collaborate, but will also require the attendance of additional resources from outside the area as a matter of urgency. Some of the additional teams may be not authorised subscribers on the PSN. Furthermore, radio equipment brought by those teams will not be interoperable with the local communication system.
Resources entering the building to tackle the fire and/or rescue people inside will require the use of direct-mode (back-to-back) communication as radio coverage from base-stations may not stretch to the interior of buildings and will certainly not deliver to subterranean levels.
Although secondary in importance to reliability, public safety communications applications used in the incident response would be considerably enhanced by broadband transmission capabilities. Large amounts of data could then be exchanged between the responders and the emergency control centres and other involved facilities (e.g. hospitals).
The PSN will be stretched to capacity simply by the attendance and requirements of the local emergency crews. Immediately resources start to arrive from outside the area, the network capacity may be exceeded. From the outset, some communications will take place across the mobile cellular network and this will increase as it becomes more difficult to get through on the PSN.

1.5.- Focus Areas
The description of the Project HELP operational scenario [5] includes a timeline of events, where the evolution of the incident raises the need for many different communications among many different actors and where a number of limitations in terms of communications needs become evident during the incident. Arisen limitations have been captured under the concept of focus area that represents the key stress-points (i.e. those where the public safety services and/or technical systems would be under maximum strain) within the operational scenario that shall be addressed by the envisioned solution framework. Three focus area are identified:
• Providing enough communication capacity for PS units in the incident area. The high concentration of first responders in the incident area makes the PSN to be over capacity. If arriving PS out-of-area support units do not bring additional on-board capacity (e.g. fast deployable base stations), then they will add significantly to the load already being placed on the networks. Also, the capacity/coverage provided by infrastructure networks may not match the spatial/temporal capacity/coverage needs across the affected area. In turn, the limited available capacity and/or the lack of broadband connectivity at scene would put some limits on the utilisation of advanced equipment for emergency response which might be used by attending specialist PS support units. Even in case that priority access for PS users to public mobile networks is supported, organisational complications in managing the priority service frequently renders it virtually useless.
• Facilitating communications interoperability between PPDR units (local, support and command). In the considered scenario, supervisors at the scene are unable to communicate/coordinate between each other across emergency services due to interoperability issues between dedicated PS systems (e.g. PSN/VHF). First responders arriving from other area, even those equipped with compatible technology (e.g. TETRA), are unable to use existing PSN infrastructure. There is no capability to set up inter-agency channels when users are spread over several networks. Furthermore, there is a lack of coordination in the configuration of radio equipment brought to the incident area by different agencies.
• Coping with sudden network base-station failure during the incident response. It is highly probable that in this scenario, the PSN base-station would have failed before tactical-level command units are properly established. Unless these units are able to move onto other networks, there is a very real risk that police and ambulance tactical-level control centres would be unable to carry out a major part of their role for some considerable time. Nevertheless, the usage of commercial network as alternative communication means when PS base station fails is up to PS responders and not an automatic procedure at all. Relying only on back-to-back communications after PSN base-station failure is likely to turn on some on-scene resources unable to communicate with their respective tactical-level control centres due to the limited transmission range of individual terminal equipment.

2.- Project HELP solution
The proposed solution framework is targeted to create and exploit synergies of composite radio systems encompassing commercial and PMR networking technologies. The proposal is built upon the convincement that only a solution that takes into account multiple wireless communications technologies and strategies can address the complex requirements of modern emergency and disaster relief communications. Therefore, the proposed solution framework is built on the following two pillars:
• The capacity and efficiency of public safety communications networks can be increased by implementing “network sharing” concepts between different PSNs as well as among PSNs and PMNs. Hence, existing communication resources in the incident area will be potentially exploited for use by public safety organisations as well as for direct communication with the population.
• Network capacity and efficiency can be increased by implementing “spectrum sharing” techniques between public safety and commercial networks in case of emergencies or natural or man-made disasters. One example of “Spectrum sharing” refers to the possibility of managing spectrum in a flexible way and pooling the spectrum among different public safety license holders.

Project HELP has developed a high-level functional model intended to overcome the limitations of the considered operational scenarios and to satisfy the corresponding user and system requirements [5][6]. The functional blocks that form part of the Project HELP functional model are depicted in Figure 2 and briefly described in the following [7]:
• Management of user and service provisioning. The scope of this functional block is to enable roaming and service interoperability across different PSNs and/or PMNs that will provide access to PPDR services. This will be achieved by means of:
- Management of user and terminal related data and required interworking solutions that will allow PPDR users to be able to roam on networks other than their home networks, such as commercial PMNs.
- Management of PPDR service provisioning solutions that are able to provide access to PPDR services from both PSNs and PMNs and support service interworking between PPDR users connected through different networks. Service interworking with legacy networks shall be accounted.
• Management of priority access services. The scope of this functional block is the management of preferential treatment for PPDR traffic in PMNs. This management will allow e.g. controlling the activation of priority services and the establishment of the operational policies for those services. Priority services to give precedence to some PPDR communications shall be consistently offered through PSNs, PMNs and Incident Area Networks (IANs) allowing for pre-emption and different levels of prioritisation. The management of the priority services should consider PPDR users’ access rights and role within the incident command structure, the type of application, allow for content prioritisation as well as consider the context and location of communication endpoints.
• Dynamic spectrum management. The scope of this functional block is the management of the spectrum available for PPDR communications in the composite scenario. This management is driven by a two-fold target:
- To exploit additional spectrum for PPDR communications in an emergency situation.
- To unleash dedicated PPDR spectrum for other uses when it is not needed for PPDR.
• Dynamic capacity and coverage management. The scope of this functional block is the management of the distribution of capacity and coverage in the incident area. This encompasses:
- Management of the gathering of capacity/coverage operational needs.
- Configuration of transmission parameters in base stations, terminals and deployable equipment.
• Situational awareness. The scope of this functional block is the gathering of accurate information regarding the status of communications services in a disaster area. It provides support to the other resource management functionalities and enables the sharing of data and information between involved actors.
2.1.- System view
Project HELP system view of future PPDR communications is illustrated in Figure 3. This system view is built upon the following pillars that have been established to guide the development of the proposed solution:
• Adoption of commercial Long Term Evolution (LTE) standards for mobile broadband PPDR.
• Coexistence of dedicated LTE-based PSNs and PMNs in most plausible future PPDR network scenarios.
• Interworking with legacy systems and adoption of PMR/LTE multimode UE.

A. Adoption of commercial LTE standards for PPDR
Technological advances in the commercial domain have lead to top-of-the-line radio technologies able to achieve performance levels close to Shannon’s bound. The state of the art of commercial wireless technology evolution is LTE mobile broadband technology, currently positioned to be the dominant technology in future commercial mobile networks. LTE is part of the GSM evolutionary path for mobile broadband, following EDGE, UMTS, HSPA and HSPA Evolution (HSPA+). The overall objective for LTE is to provide an extremely high performance radio-access technology that offers full vehicular speed mobility. LTE capabilities include downlink/uplink peak data rates up to 300/75 Mbps with 20 MHz bandwidth, operation in both TDD and FDD modes and scalable bandwidth from 1.4 MHz up to 20 MHz [8]. Average spectrum efficiency figures for LTE Release 8 are around 1.75 and 0.75 b/s/Hz/cell for the downlink and uplink respectively, higher than other similar systems such as WiMAX and HSPA [9]. LTE provides a full Internet Protocol (IP) network architecture and is designed to support all services over IP connectivity, including voice over IP (e.g. Voice over LTE [VoLTE]). LTE is already on the market in some countries and many trials and developments are underway. LTE has been designed to provide a high-rate, very low latency IP connectivity service between UE and external Packet Data Networks (PDNs) such as the Internet or any private IP-based network to which the LTE network provides access. This IP connectivity service can be utilised by almost any application relying on IP communication, enabling a large number of services to be provided over LTE networks. The LTE IP connectivity service can provide differentiated treatment to IP traffic flows with different Quality of Service (QoS) requirements in terms of required bit rates as well as acceptable packet delays and packet loss rates. Many of the new demanded PPDR data services can be implemented in client and server applications residing on terminals and network servers that only require the LTE network IP connectivity service. Therefore, many existing and emerging applications running on top of IP connectivity can be readily made accessible also for LTE users (e.g. remote access to databases, operational information uploading/downloading, mobile office applications, Internet access, etc.). Besides, standardised commercial technologies for the provisioning of IP-multimedia services such as IP Multimedia Subsystem (IMS) [8] can also be exploited for the realisation of PPDR services.
The adoption of commercial mainstream LTE technology to deliver increasingly data-intensive applications demanded by the PPDR agencies is getting a strong momentum among the PPDR community. As a matter of fact, in January 2011, FCC in US adopted a Third Report and Order (Order) and Fourth Further Notice of Proposed Rulemaking (FNPRM) to support the build out of a nationwide broadband network based on LTE Release 8 [10]. Also in Europe LTE standard is increasingly backed by the PPDR community and considered within European Telecommunications Standards Institute (ETSI) as a potential candidate for the evolution roadmap of TETRA [11]. The use of LTE technology for broadband PPDR has also been endorsed by many stakeholders contributing to CEPT Project Team FM49 started in September 2011 and tasked to identify and evaluate suitable bands for European-wide harmonisation of spectrum for PPDR [12].
The following arguments were presented in the FM49 meeting held in November 2011 as to the adoption of LTE versus the development of a dedicated PPDR broadband technical standard [14]:
• A PPDR specific standard would reflect a relatively low volume market (compared to the commercial mobile broadband market), which would result in higher costs for infrastructure, as well as for the end user devices. One relevant comparison would be to look at the cost of a TETRA base station, and compare it to a GSM base station. The price of a TETRA base station is at least double the price of a comparable GSM base station. If a comparison is made between GSM and TETRA terminals, the difference in price is even bigger.
• An introduction of a new and dedicated PPDR technical standard would limit the interoperability between those countries that will make a diverting choice to use commercial technical standards for PPDR broadband such as HSPA and LTE.
• The introduction of a new and dedicated PPDR broadband technical standard, the associated equipment manufacturing, and the development of user applications supporting this standard may delay the introduction of a PPDR broadband system in Europe.
• A dedicated PPDR standard may not be able to keep up with the technology developments of the fast moving and high volume commercial mobile broadband market.
• It will be easier to harmonize new spectrum for mobile broadband, where PPDR broadband can be included, than to find the necessary support for additional dedicated spectrum to be used exclusively for PPDR broadband.
Indeed, as reported in deliverable D2.3 [15], the foreseen synergies with mass market LTE handsets and their components and software is one of the main reasons of the PPDR users to consider LTE technology: computing and communication capabilities of commercial terminals (e.g. smartphones), orchestrated through powerful Operating Systems (OSs) and related Software Development Kits (SDKs), are seen also as a versatile platform for the development of PPDR-oriented services and applications. LTE interface of PPDR terminals shall be compatible with commercial networks and, at the same time, may have added functionality when connected to LTE PPDR broadband technology (e.g. protocol enhancements for increased robustness in degraded network conditions, direct communication mode, etc.).
The adoption of LTE for mobile broadband PPDR is also backed by TETRA and Critical Communications Association (TCCA) (former TETRA Association) [16]. In March 2012, TCCA has established a Critical Communications Group (CCG) to drive forward the creation of mobile broadband solutions for Mission Critical users. The main technology the group will be promoting is LTE and the first task of the group is to define requirements for the LTE standardisation in the framework of the 3GPP.

B. Coexistence of dedicated LTE-based PSNs and PMNs
A wide consensus exists among PS users on the need of dedicated PS Networks (PSNs) for mission-critical communications since commercial Public Mobile Networks (PMNs) are not considered to provide the degree of service availability, reliability and security required for PPDR operations. Nevertheless, the huge investment required to roll out nationwide dedicated PSNs may not be deemed convenient or even affordable for some public administrations. Hence, while some countries can deploy new dedicated PSNs for broadband PPDR services with nationwide coverage, others may decide to cover only some critical areas with dedicated infrastructures or even rely exclusively on commercial networks for the provisioning of PPDR broadband.
Even in the case that dedicated broadband PSNs can be rolled out, the unpredictable nature of an incident in time, place and scale, renders virtually impossible to ensure that first-responders will have proper support only from the PSNs for radio communications during the emergency (e.g. due to lack of coverage, capacity, damaged infrastructure, etc.).
In this context, the coexistence of dedicated LTE-based PSNs and PMNs is expected to be commonplace in most plausible future PPDR network scenarios. Apart from the benefits that might come from a financial point of view [15], there should be a number of other advantages of using commercial networks for PPDR broadband that need to be further considered [14]:
• Network redundancy. Network redundancy could be realized in several ways, e.g. using national roaming subscriptions, Subscriber Identity Module (SIM) cards registered in another country with roaming agreements, or some sort of multiple SIM-card solution.
• Capacity. Due to the access of larger spectrum bandwidths, a commercial network has the potential to provide higher capacity at extreme emergency situations. Priority functions and other measures could be included in commercial broadband networks to cater for the PPDR needs for ubiquitous communication resources.
• Up to date technology. Commercial operators may be more likely than public owned networks to have the financial ability to upgrade the network with the latest technology. This would also apply for end user devices and applications. In addition, based on the requirements for backward compatibility, handsets from previous versions of commercial standards can still operate on the networks of today.
• Increased network reliability through alternative investments in commercial infrastructure. The commercial networks are considered to be an important part of a society’s infrastructure, and lots of effort is made to improve the commercial networks security, robustness, and ability to resist for example power shortages or transmission losses. If parts of the cost associated with realizing a dedicated PPDR broadband network could be used to increase the robustness and security of the commercial networks, this would also lead to several social-economic advantages.
Building on the previous statements, Figure 3 illustrates the utilisation of mobile LTE-based PSNs and PMNs for the provisioning of PPDR services. One illustrative example reflected in Figure 3 is the fact that access to specific PPDR services (e.g. online secure access to PPDR databases) shall be possible while connected to a commercial network and in a transparent manner for PPDR users.

C. Interworking with legacy networks and adoption of PMR/LTE multimode terminals
Dedicated LTE-based PSNs are to complement, not to replace, legacy TETRA/TETRAPOL/Analog PMR network infrastructures already deployed for land mobile communications and expected to continue to be the standards for mission critical voice service for the next 10 years or more. In this context, service interworking for some legacy PMR services is to be of great value to PPDR users. As an illustrative example shown in Figure 3, service interworking will enable group call communications among PPDR users connected through legacy and LTE-based PSNs as well as PMNs The adoption of multimode UE with legacy PMR and LTE radio interfaces is regarded as a pivotal element to fully exploit the potential of such a composite wireless network scenario. In case that cost aspects could limit the adoption of multimode terminals with both LTE and legacy PMR interfaces, separate terminals can still be used to access to the different services (e.g. LTE terminal to access data-oriented services and legacy PMR terminals for voice-centric services).
2.2.- System architecture
The system architecture adopted for the Project HELP solution is primarily driven by the design approach adopted for the realisation of the functional blocks concerning the management of user and service provisioning and the management of prioritisation access services. The resulting system architecture is then expanded to support advanced functionalities along with their corresponding management framework concerning dynamic spectrum management, dynamic capacity and coverage management and situational awareness. The overall scope of the proposed Project HELP solution is illustrated in Figure 4. This section addresses the description of the system architecture while the development of the advanced functionalities and their management aspects is covered afterwards.
According to the Project HELP functional model, the system architecture shall encompass capabilities for (1) facilitate roaming and enabling PPDR service delivery through PSNs and PMNs in a secure and interoperable manner and (2) ensuring a proper allocation of networks’ capacity to PPDR users according to established prioritisation policies. Though several approaches are possible, a solution allowing PPDR users to have a tight control of the mentioned capabilities is proposed in Project HELP. This approach can satisfy reliability requirements demanded by the PPDR community. The proposed system architecture is depicted in Figure 5.
The system architecture is sustained in a core infrastructure that consists of 3GPP IP Multimedia Subsystem (IMS) functions, application servers and a given set of 3GPP network components (i.e. Home Subscriber Server [HSS], Policy and Charging Rules Function [PCRF] and Packet Data Network Gateway [P-GW]), all interconnected by means of a private IP network. Further details on the role and operation of these elements are covered in next sections. This core infrastructure is used to provide PPDR services to users in the field equipped with LTE-enabled PPDR terminals through a number of dedicated LTE-based PSNs and/or commercial PMNs interconnected by means of standardised 3GPP interfaces (e.g. S5/S8 for data transfer and S6a/S6d for signalling transfer, as depicted in Figure 5). This core infrastructure is also interconnected through e.g. Application Programming Interfaces (APIs) to Control Rooms Systems (CRS) used by PPDR users for tactical and operational management. CRS can include dispatch applications to access the PPDR services (e.g. dispatch positions to communicate with users in the field) as well as control and monitoring applications to deal with administrative and operational issues of the provided PPDR services. The operation of this core infrastructure, along with the dedicated PSNs, is to be managed by a PSN operator through a Network Management System (NMS). The core infrastructure also embraces the gateway (GW) functions needed to interwork with legacy TETRA/TETRAPOL/Analog PMR network infrastructures.
Over such a basis, further details on the required capabilities for PPDR user and service provisioning management, priority access management and interworking with legacy systems are provided in next subsections.

A. Management of user and service provisioning
The basic architecture of a LTE network for the delivery of IP-based services to mobile terminals is illustrated in Figure 6. A LTE network consists of two main parts: a radio access network based on OFDMA technology, termed as Evolved UMTS Radio Access Network (E-UTRAN), and an enhanced packet-switching core network termed as Evolved Packet Core (EPC) that is fully based on IP technologies. E-UTRAN is mainly in charge of radio transmission functions while session and mobility management functions are handled by the EPC. E-UTRAN consists of base stations termed as evolved NodeBs (eNBs) providing the radio interface towards the UE and connected to the EPC via the S1 interfaces (i.e. S1-MME for the control plane and S1-U for the data plane). An interface denoted as X2 has been also defined for the interconnection of eNBs. This interface is to be used for e.g. handover optimisation purposes and inter-cell interference coordination. The EPC comprises one a network entity called Mobility Management Entity (MME) to handle control functions (e.g. authentication of users, location management, etc.) and two entities through which the user data traffic is transferred: a Serving Gateway (S-GW) that anchors user traffic from/to E-UTRAN into the EPC; and a PDN Gateway (P-GW) that provides the IP connectivity to the external IP networks. The operation of the EPC is assisted by the Home Subscriber Server (HSS), a central database that contains, among others, user subscription-related information. The LTE IP connectivity service is realised through the establishment of so called Evolved Packet System (EPS) bearer services between the UE and the P-GW. The EPS bearer represents the level of granularity QoS control in E-UTRAN/EPC and provides a logical transmission path with well-defined QoS properties. IP-based service control platforms such as 3GPP IMS and related application servers can be used on top of the QoS-aware LTE connectivity service to support advanced multimedia services. 3GPP has also specified a Policy and Charging Control (PCC) system which provides operators with advanced tools for service-aware QoS and charging control. The PCC architecture, through the Policy and Charging Rules Function (PCRF) network entity, enables control of the EPS bearers (e.g. QoS settings) for both IMS and non-IMS services. Figure 6 illustrates the LTE network components and the main interfaces among them as well as the concept of EPS bearer service.
-User management
Access to a LTE network is dependent on a subscription to an operator. A subscription provides the user with, among others, a subscriber identity (i.e. IMSI) and security credentials (e.g. secret keys) needed for authentication and authorisation purposes within network access control procedures. On the terminal side, this subscription information is stored in the Universal Subscriber Module Identity (USIM) module. On the network side, this information together with other subscription-related information such as service profiles (e.g. default QoS settings) are centrally handled within the HSS database of the operator. Keeping control over such PPDR subscription information is essential to tactical and operational PPDR managers since it allows PPDR users to completely manage the user provisioning process (e.g. activation/removal of subscribers) as well as setting up required subscriber capabilities (e.g. subscriber service profiles). Therefore, as depicted in Figure 5, the envisioned solution considers that PPDR users will deploy their own HSS as part of the core infrastructure and issue and control their own USIM cards.
This solution would be the natural choice in case PPDR users can afford deploying dedicated LTE-based PSNs. Dedicated networks will have its own Public Land Mobile Network Identifiers (PLMN ID) and PPDR users, or a governmental agency on their behalf, would serve as full Mobile Network Operators (MNO). In case that no dedicated PSNs are used, the proposed solution can be seen as a possible realisation of the Mobile Virtual Network Operator (MVNO) model in which the MVNO has its own PLMN ID but exclusively relies on the network capacity provided by other commercial MNOs.
In addition to enhanced subscriber management control, this solution avoids PPDR users ending up with a number of separate subscriptions to different commercial operators (i.e. handling multiple USIMs and using terminals with multi-SIM support) as well as it provides independence from commercial MNOs through the ability to switch among them or support a number of them without changing PPDR users’ USIM cards. The realisation of this solution requires roaming agreements to be established among PPDR users and commercial operators and the deployment of the signalling interfaces needed to support the roaming service (i.e. 3GPP S6d interface) between the PPDR core infrastructure facilities and the participating commercial PMNs. Control and administration of PPDR subscribers’ data can be realised through specific User Management Applications integrated within CRS, as depicted in Figure 5.
-Service provisioning: IP connectivity service
The proposed solution also considers that the PPDR core infrastructure will integrate its own dedicated P-GW. This provides a secure access to the PPDR core infrastructure and allows PPDR users to autonomously manage the IP connectivity service (e.g. private IP address allocation). Besides, connection mobility between PSNs and PMNs without service disruption is facilitated since the P-GW serves as a mobility anchor point for PPDR traffic. Hosting the P-GW within the PPDR core infrastructure requires the deployment of an additional interface (i.e. 3GPP S8 interface for user traffic depicted in Figure 5) with commercial networks, which will be required to support the use of a P-GW that resides out of their networks (i.e. home routed roaming configuration in LTE).
-Service provisioning: PPDR service delivery platforms
A diverse range of data, imaging and multimedia applications is currently in demand within the PPDR community. Demand is being driven by changes in working practices, requiring access to a far wider range of multimedia sources (textual, images and video). Examples of required mobile data applications are video on location, mobile office applications, downloading/uploading of operational information from/to control rooms to/from field units, online database enquiry, etc. [17]. These services are not expected to replace but complement the traditional rich set of voice services nowadays in widespread use within the PPDR community such as group voice calls and short data messaging.
Many of the new demanded PPDR data services can be implemented in client and server applications residing on terminals and network servers that only require the LTE network IP connectivity service. Therefore, many existing and emerging applications running on top of IP connectivity can be readily made accessible also for LTE users (e.g. remote access to databases, mobile office applications, Internet access, etc.). Commercial or PPDR-customised Mobile Virtual Private Network (VPN) solutions [18] can also be used to provide a secure access between the client and server applications endpoints. Besides, standardised commercial technologies for the provisioning of IP-multimedia services such as IMS can be leveraged for the realisation of multimedia PPDR communications over LTE. IMS is a service platform that provides a control layer for establishing and managing media sessions, for example voice communications and multimedia calls, on top of IP networks [19]. The IMS control layer is based on Internet Engineering Task Force (IETF) open standard core networking protocols such as Session Initiation Protocol (SIP). In this regard, IMS applications such as Push-to-Talk over Cellular (PoC) [20] developed by Open Mobile Alliance (OMA) can be adopted for the implementation of PPDR services based on one-to-many communications capabilities. These communications capabilities may extend from voice, as commonly used in traditional PMR networks, to text messaging, video, and other forms of data communications (e.g. PoC can support communication of live-streamed pictures among group call participants). Indeed, OMA PoC already includes some support for dispatcher functionality and interworking with non-OMA PTT systems (e.g. legacy PMR systems). The realisation of the PoC is coupled with two other services also defined by OMA: the presence service and the group management service. The presence service can be used to keep track of important information such as other users’ current availability to communicate and their geographical location. The group manager enables a flexible management of the definition and characteristics of groups involved in PoC sessions. IMS applications can reside either in the operator’s network or in third-party networks. The deployment of PPDR services over mainstream IMS technologies is currently supported by some vendors [21][22], though proprietary solutions with similar characteristics are also arising [23]. In the longer term, the deployment of PMR-like services over IMS and LTE (e.g. mission critical Push-to-Talk over LTE) is key to facilitate the convergence of legacy PMR services and emerging data-intensive / multimedia PPDR services into the same mobile broadband network infrastructure.
As depicted in Figure 5, enabled by IP connectivity through the PPDR P-GW located at the core infrastructure, the delivery of PPDR services relies on the IMS service control functionalities (e.g. registration for IMS service reachability, routing of SIP signalling, etc.), a number of server applications (e.g. PoC server, database server, etc.) and a number of related client applications installed in user terminals. Dynamic management of the provided service capabilities is possible through specific Service Management Applications within CRS so that PPDR users in control rooms could adjust PPDR service provisioning to specific operational needs (e.g. creation of groups, activation of database access, etc.). Solutions for terminals’ client applications downloading and installation can also be considered for PPDR terminal programming and customisation (e.g. the likes of popular applications’ stores in the commercial domain), along with other post-manufacturing configuration of terminals performed via Mobile Device Management (MDM) software solutions.

B. Management of priority access
The possibility to ensure that important connections/calls are always established is essential for mission-critical PPDR communications. Preferential treatment for access to and utilisation of LTE network resources can be supported as a realisation of the Multimedia Priority Service (MPS) specified by 3GPP. MPS allows certain subscribers to obtain and maintain radio and network resources with priority in situations such as network congestion, creating the ability to deliver or complete sessions of a high priority nature. MPS is applicable to IMS based multimedia sessions as well as other data services that might not use IMS functions. A regional/national authority shall define and assign one out of n possible user priority levels to each MPS subscriber. Then, the implementation of the priority treatment for MPS in LTE networks primarily relies on the proper mapping of MPS priority levels to the QoS parameters of the EPS bearer(s) employed in a MPS session and on the exploitation of mechanisms such as access class barring of E-UTRAN.
An EPS bearer is always characterised by a QoS profile that includes at least two parameters: QoS Class Identifier (QCI) and Allocation Retention Priority (ARP). On the one hand, QCI is used to indicate whether the EPS bearer has to be allocated with reserved resources (Guaranteed Bit Rate [GBR] bearer on non-GBR bearer) and the configuration and expected traffic forwarding treatment to meet some target performance requirements (e.g. packet delay budget, packet loss ratio, etc.). On the other hand, the ARP contains information about the priority level (scalar value from 1 to 15), the pre-emption capability (flag) and the pre-emption vulnerability (flag). The priority level defines the relative importance of a resource request. This allows deciding whether a bearer establishment or modification request can be accepted or needs to be rejected in case of resource limitations. It can also be used to decide which existing bearers to pre-empt during resource limitations, though the consideration of pre-emption in MPS priority levels is subject to national/regional regulatory requirements. Decision-making on the appropriate setting of EPS bearer’s QoS parameters is handled by the PCRF according to network operator policy. Inputs for PCRF decisions can consists of subscription related information (e.g. MPS priority level) as well as dynamic session information provided to the PCRF by application servers and/or IMS platforms involved in user session signalling (e.g. interface Rx shown in Figure 6).
With regard to access class barring, MPS subscribers are entitled to be members of one or more out of 5 special categories (specified as access classes 11 to 15). Information about permitted classes is signalled over the air interface in a E-UTRAN cell by cell basis indicating the access class(es) of subscribers barred from network access. This allows the network operator to prevent overload of the radio interface control channels under critical conditions by restricting access attempts to some users. More details on access control mechanisms and the MPS have been reported in D3.1 [24].
The solution depicted in Figure 5 is the proposed realisation of the MPS within the Project HELP solution where PCRF functionality is allocated within the PPDR core infrastructure. In addition to the PCRF entity, the proposed implementation also entails the following 3GPP functional entities: Application Function (AF), located within IMS and application servers and needed for dynamic invocation of MPS and to transfer dynamic session information to PCRF (e.g. requested media types and session/application priority extracted from SIP signalling); the Service Profile Repository (SPR) that contains subscriber related information (e.g. user’s MPS priority level, user’s allowed services, etc.) and can be integrated within the HSS; and the Policy and Charging Enforcement Function (PCEF), located at P-GW and used to enforce the policy decisions in the user data plane (e.g. rate control, etc.). This solution enables operational and tactical PPDR managers in control rooms to have direct control on the priority policy applied to PPDR traffic. So, through Priority Access Management Applications in CRS interacting with the PCRF element via specific APIs, PPDR managers would be able to configure the information and rules used by the PCRF element within the PPDR core infrastructure for QoS decision-making (e.g. choice of ARP and QCI values). The key functional entities and related standardised interfaces (i.e. 3GPP interfaces Rx, Sp and Gx) needed for the realisation of this priority access management solution are highlighted in Figure 7.
The proposed solution would allow PPDR users to enforce the desired priority access policies, which may consider not just the relative priority of a particular user based on their agency affiliation but also the situational context of applications (e.g. PPDR users’ role within an incident command structure, type of incident, the applications that are mission-critical and must be prioritised, location of users, etc.). Though some priority access policies can be generic and valid in most operational scenarios (i.e. pre-defined policies), others may require to be tailored to specific crisis incidents, resulting in a mix of automated system but enabling human intervention.
The deployment of this solution through commercial PMNs requires policies and related QoS parameters used for prioritisation management to be harmonised and agreed by both the commercial operators and PPDR users (e.g. ARP values assigned by PPDR users for PPDR traffic and those assigned by the commercial operator for commercial traffic must be consistent). Besides, limits on the maximum allocated capacity for proper PPDR and commercial traffic sharing shall be determined as well. The establishment of a crystal-clear, validated policy framework for prioritisation management is essential for both the PPDR and commercial community to avoid uncertainties in situations of network congestion, and, eventually, to increase their trust over the operation of prioritisation. All these aspects must be considered in the formulation of the roaming agreements to be established among PPDR users and commercial operators.

C. Service interworking with legacy networks
Current preferred solutions for service interworking with legacy networks consist in developing a gateway (GW) between the existing PMR network and the guest network and a dedicated application in order to export the features / services from the existing network (see GW functions component in Figure 5). The guest network refers to any type of network through which terminals can connect to the gateway component and access PMR services. In Project HELP the guest networks are LTE-based dedicated PSN and commercial PMN, though the solution is extensible to any other network type (e.g. ad-hoc network) that provides IP connectivity services among terminals and the PMR gateway. In this solution, the gateway behaves as a base station (BS) from the PMR network point of view. On the other hand, the gateway is considered as an application server (e.g. VoIP server) from the guest network point of view. SIP protocol is used as the control protocol between the gateway and the client applications embedded in the guest network terminals. This protocol allows managing the subscriber registration, the group affiliation, the group call establishment and the Push-To-Talk feature. The terminals are then considered as SIP clients and the gateway as a registrar and a SIP proxy. In order to transport the voice, RTP (Real-Time Transport Protocol) can be used. RTP has the advantage to be compatible with the IP multicast addressing in case that IP multicast can be used in the guest network for the group call service: the upward voice flow (from the guest terminal to the gateway) is a unicast flow; the downward voice flow (from the gateway to the guest terminal) is a multicast flow, if supported by the guest network. The correspondence between the group calls and the IP multicast addresses is managed in the gateway. For security purposes, the gateway can be placed within a DMZ (DeMilitarized Zone) created with a firewall placed upstream from the plug to protect the PMR network from guest networks, another firewall into the gateway to protect the gateway from guest networks and a link between the PMR network and the gateway. Confidentiality, integrity and authenticity can be maintained with an encryption system.
Figure 8 provides an overview of a prototype for this type of solution being developed by Cassidian. In particular, the depicted solution interconnects a TETRAPOL IP network with a guest network which can be e.g. ad hoc, Wi-Fi, WiMax or LTE. The prototype is made up of a gateway connected to the TETRAPOL IP network and to an ad hoc guest network and guest clients, nodes on the ad hoc network. The gateway converts TETRAPOL protocols to SIP and RTP protocols and vice versa, in order to offer a group call services on both sides.
2.3.- Advanced functionalities and management framework
The system architecture, which provides the key capabilities related to user management and service provisioning across different networks, is expansible to support advanced functionalities such as dynamic spectrum management, dynamic capacity and coverage management and situational awareness. These advanced functionalities are expected to enable a more efficient utilisation and distribution of communications resources to improve system response to face specific crisis situations.
A. Dynamic spectrum management
Clearly, the deployment of future dedicated LTE-based PSNs raises the issue of identifying the spectrum band(s) and spectrum management model(s) on which these networks will be deployed and operated. Even though the inherent spectrum flexibility associated to LTE technology (i.e. LTE can be exploited in different frequency bands, using different transmission bandwidths -from around 1 MHz up to 20 MHz- and with different duplexing arrangements) will be a facilitator, political, regulatory and economical facets will have greater influence on the final solutions to be adopted.
The introduction of dynamic spectrum management functions is believed to be an essential step towards achieving enhanced capacity in emergency scenarios, enabling better PPDR communications and, ultimately, improving overall spectrum utilisation. Based on the analysis of spectrum sharing cases developed within Project HELP [24], five spectrum sharing models for PPDR communications have been identified:
• Dynamic transfer of exclusive rights of use, where spectrum access is restricted to the user that holds the spectrum rights of use but these rights can be exchanged among different users for a limited time or a limited space. This option embraces also the concept of Licensed Shared access (LSA) where users are granted rights to utilise parts of a given spectrum band in spatial or time domain that are unused by an incumbent user, upon agreed terms and conditions defined with the incumbent.
• Secondary access sharing models, where a primary user holds exclusive rights of use for a given spectrum band (i.e. licensee) but secondary users can access the spectrum in an opportunistic whenever the primary user is not disturbed. Two variants of this model are distinguished based on the use of a coordinated or coexistence approach among primary and secondary users.
• Collective use of spectrum (CUS), where a number of independent users and/or devices are authorised to use the same range of frequencies at the same time and in a particular geographic area under a well-defined set of conditions. Two variants of this model are distinguished based on the use of a coordinated or coexistence approach among users.
The feasibility of each sharing model for PPDR communications primarily depends on the type of users involved in the sharing framework. At European level, sharing spectrum resources among commercial, military and public safety domains is under consideration in regulatory and standardisation bodies such as CEPT [12] and ETSI [13]. The adoption of a given sharing model may require changes to the organizational structures and relationships among commercial, public safety and military entities. In some cases, these changes are just an extension of existing agreements (e.g. joint procedures for disaster management between military and public safety in large natural disasters). In other cases, new agreements (e.g. Service Level Agreements [SLA]) must be put in place. Moreover, the amount of changes required in the existing infrastructures managed by these different communities is another important aspect to consider. Any proposed sharing model should minimize or not require changes to the existing infrastructures. The adoption of a sharing model is also dependent on the development of suitable technologies and regulatory frameworks. Different sharing models may require more or less complex modifications to existing standards and undertake different technical challenges. In some cases, the technical requirements for specific functions (e.g. spectrum sensing case of models built upon CR technologies) may be difficult to implement with existing technological capabilities (e.g. computing/processing power). Furthermore, international, European and national spectrum regulations must be modified to permit the deployment of some of the sharing models. Tables 4, 5 and 6 synthesise, respectively, the discussion on the suitability of the identified spectrum sharing models considering organizational & operational aspects of involved users as well as relevant technical & regulatory initiatives that can contribute to pave the way towards their adoption.
In this context, Project HELP advocates for an hybrid solution for wide area coverage based on the joint exploitation of both dedicated and shared of spectrum for PPDR, as depicted in Figure 9. The dedicated spectrum will be exclusive use spectrum enough to satisfy regular PPDR operational needs. Indeed, investment in dedicated PSNs is believed to be fully contingent on the allocation of some amount of dedicated core spectrum. Furthermore, the allocation of dedicated spectrum can be cornerstone for PPDR community to find synergies with commercial players. Two potential possibilities for the allocation of this dedicated core spectrum are the 380-470 MHz band and the 700 MHz band, this latter under the context of a potential second digital dividend in Europe.
In addition to this core spectrum, the proposed solution also considers the exploitation of shared spectrum to face a surge of capacity demand during an emergency situation. In this regard, two non-mutually-exclusive, spectrum sharing components have been identified:
• Secondary access to TV WS by PPDR users. An analysis of the key regulatory requirements which are relevant for the potential exploitation of TV WS by PPDR applications has been addressed. On this basis, a functional architecture and related management framework needed to exploit TV WS within Project HELP solution has been covered. In addition, some possible regulatory and technical extensions intended to increase the degree to which PPDR users can rely on TV WS have been also identified.
• Dynamic transfer of spectrum rights, in the form of e.g. the LSA concept. This model can be deployed within the context of a second digital dividend in the 700 MHz band between commercial and PPDR network operators as well as in existing military bands. In this regard, a functional architecture for the exploitation of a LSA model has been proposed where a LSA spectrum manager (e.g. government entity or a third party entity which has obtained the related authorization from the spectrum regulator) is in charge of distributing the shared spectrum resource amongst PPDR and other potential sharers.

B. Dynamic capacity and coverage management
The scope of this functional block is the adaptation of the coverage and capacity of the networks in the incident area. As depicted in Figure 10, dynamic capacity and coverage management can use various techniques and approaches to increase the capacity and coverage to address the needs of PPDR users during an emergency crisis. Coverage modifications refer to the physical cell size changes that might be achieved by transmit (Tx) power adjustment or antenna rearrangement, whereby both of these methods form one group. Second group is formed by load balancing and interference coordination techniques, which are able to change network capacity in the certain area and for selected users. Additional capacity as well as coverage can also be provided by new network transmission elements deployed in field and hence, this approach based on the temporary base station or relay node deployment forms the third group. The first and the second group of capacity and coverage management techniques need to rearrange network settings only, and can be executed automatically whereas relay node (RN) and base station (BS) deployment require human involvement and are more time consuming. Some further details on these three groups of techniques are given in the following.
Dynamic coverage management of existing network elements
Dynamic coverage management of existing network elements refer to all actions related with the coverage modification that can be performed by means of existing network configuration parameters readjustment. Coverage management actions in the fully operating network might be performed in case of: (i) changes of geographical aspects e.g. new building which shadow part of cell, (ii) new base station deployment and according to interference coordination cell must be shrank, or (iii) base station failure and neighbour cell compensation. Beside the supra mentioned situations where coverage management actions are performed at the daily basis due to the changes in the network, they can be also executed on purpose e.g. to increase mobile network area to cover incident area and support PS services. The PS services utilise PMN networks for the purposes of coordination their actions in the incident area, to contact with different services and to access broadband services. If the incident takes place in the area not covered by the preferred Radio Access Technology technology or there is a failure in a base station serving this area, the coverage management actions enable to restore or extend coverage at the incident scene.
Ad hoc network elements deployment for coverage and capacity management
Transmission network elements deployment like base station or relay node is considered in case of an accident when the PMN coverage must be extended rapidly and that cannot be performed by the PMN reconfiguration or in case when existing infrastructure was damaged and must be rapidly recovered. Such situation is captured in the Project HELP operational scenario [5] and describes a sudden PSN base station failure during the incident response that causes all ambulance and police communication to revert to back-to-back mode. In case of incident, the traditional deployment process is not applicable due to time constrains. Both, BS and RN, considered to be rollout in the scene of incident must be mobile, moved and setup in short time, and include self-power source and mast for antenna. Additionally, BS shall be able to connect to multi types of physical connection to backhaul (e.g. optical fibres, ADSL, microwaves).
Dynamic network capacity management
Dynamic network capacity management refer to all actions related with the capacity modification that can be achieved by the network parameters reconfiguration only. Load Balancing (LB) algorithms shift traffic from the heavy loaded cells to less loaded neighbours. The LB mechanism has been originally developed in order to improve PMNs performance and reduce costs but it can be utilised to manage the network in the incident area for PPDR services purposes. In radio communication systems interference is a main limiting factor for correct data reception. A high level of interference can result into the utilisation of less spectral efficient modulation and coding schemes as well as increased data retransmissions, decreasing network capacity. Inter cell interference coordination (ICIC) methods partially manage the interference problem at the cell edge and enable managing network capacity.
Functional architectures for the realisation of above methods have been developed in the Project [25].

C. Situational awareness
The scope of this functional block is the gathering of accurate information regarding the status of communications services in a disaster area. It provides support to the other resource management functionalities and enables the sharing of data and information between involved actors.
During an incident, many stakeholders are involved and all can provide useful information to the other ones. Considering all the sequences of an incident, there is a clear need to share information between the following stakeholders: Citizens and Emergency Response Centres; Dispatchers and First Responders belonging to the same agency; Cross-agencies (e.g. Fire and Rescue and Police); Agencies at different levels (from a regional level to a country level); Authorities of neighbouring countries; and Authorities and citizens.
Currently, there is a real trend to share the information through data communication. Many agencies made significant investment in order to computerise their "operational" processes. They are equipped with Computerised Aided Dispatch (CAD) solutions able to collect and store all the information related to an incident. Then, CAD sends the information to mobile units equipped with Mobile Data Terminals, through PMR networks. One major concern is the lack of interoperability for data exchange between agencies: agencies do not use the same shared wireless or wired networks, and the content of the data has to be agreed between both parties. At the international level, there are some standardisation groups who define the content of the information to be exchanged between agencies (for instance, Common Alerting Protocol [CAP] from the OASIS group). Nevertheless, it must be recognised there are few practical implementations on the field.
Information gathering functionality regarding the status of communications services in a disaster area is also a key component to be included as part of the situational awareness functional block. This kind of system is indeed already deployed by some administrations, such as the Disaster Information Reporting System (DIRS) system deployed by FCC in the US [37]. DIRS is a voluntary, web-based system that communications companies, including wireless, wireline, broadcast, and cable providers, can use to report communications infrastructure status and situational awareness information during times of crisis. In the context of the Project HELP solution, this knowledge about the status of communications infrastructures in the incident area is to be exploited by the dynamic spectrum management and the dynamic coverage and capacity management functions.

2.4.- Required further progress
For a full exploitation of all the capabilities considered within the proposed solution framework, further progress is still expected on LTE technologies/networks, regulatory aspects concerning roaming with priority access for PPDR and spectrum regulations concerning the dynamic spectrum management solutions. In particular:
• From LTE technology/networks point of view, PPDR community is expected to benefit from the development of cost effective solutions for the PPDR niche markets (compact core networks, lightweight Cells On WheelS [COWS], etc.). Further progress on the support of capabilities such as device-to-device communications and relaying would further contribute to increase the suitability of the LTE technology for PPDR service provisioning. Also, advances in the context of network management capabilities (e.g. Self-Organising Networks [SON]) are highly desirable, particularly in terms of dedicated software applications for network reconfiguration according to PPDR services needs. Further progress is also expected on the development of applications/service solutions over LTE tailored to satisfy PPDR needs.
• Regulation of PPDR roaming and priority access is a key issue that also deserves further attention. As discussed in the proposed solution, a validated policy framework for prioritisation management (technical, operational) is essential for both the PPDR and commercial community to avoid uncertainties in situations of network congestion, and, eventually, to increase their trust over the operation of prioritisation. All these aspects must be considered in the formulation of the roaming agreements to be established among PPDR users and commercial operators.
• Spectrum regulation, as a central enabler for the deployment of broadband PPDR communications. A European wide consensus on the spectrum bands and regulatory regime to be used for broadband PPDR is needed to establish a clear legal and business framework able to raise the public and private investments required for the delivery of multimedia, data-oriented PPDR services.

2.5.- Techno-economic implications
Project HELP solution framework builds a toolset making the smooth introduction of the LTE technology into PPDR ecosystem possible, letting the PPDR community benefit from the synergies in composite radio systems. Allowing the interoperability with legacy technologies (e.g. TETRA), Project HELP solution framework lets the PPDR community start a smooth process of migration, based on coexistence of both technologies. The advantages of Project HELP solution are not only related to the broad range of covered end users needs, but have deep economical roots:
• Sharing of the infrastructure with the PMN operators (passive sharing of locations, active sharing of RAN/backhaul/core network components, roaming services or status of MVNO combined with the prioritisation) lets PPDR community optimise or reconsider the need and time line of investment processes, adequately to the scale of the budget, balancing between OPEX and CAPEX. It means that dedicated infrastructure will be no more the only option for PPDR communications.
• Using equipment developed for the mass market instead of niche products (e.g. TETRA based solutions) PPDR users will profit from the economy of scale and high competition between vendors. The same applies for the market of end user devices and dedicated software, where even stronger competition should be expected.
• Spectrum sharing techniques will allow for more efficient distribution of resources between PPDR and other users (e.g. commercial PMNs). The spectrum sharing concept itself together with the variety of possible spectrum sharing models provide an additional dimension that will facilitate the establishment of cost-effective and win-win solutions for composite radio systems, able to exploit the synergies created by the technical solutions proposed in Project HELP.
• Toolset and techniques developed or inspired by the PMN operators for efficient network management will be also applicable to PPDR networks.
Implementation of the Project HELP solution framework using the LTE standard will also result in changes of the market structure. Figure 11 depicts current market activities, assigning the identified roles to the market players. A role represents an activity related to a particular process that can be played by one or more market players, where a process is a method that fulfils one or more needs of the PPDR users. A summary of the impact of the Project HELP technical solutions on the market is given in the following.

A. Management of user and service provisioning
Leveraging of mainstream commercial standards and technologies impacts on producing processes of terminals and infrastructure equipment. Hence, manufacturing of PPDR equipment is expected to include some components that will be common with commercial cellular equipment (e.g. radio chipsets, terminal operating systems, etc.). Nevertheless, PPDR equipment is still expected to require a level of customization (e.g. ruggedized terminals, higher robustness to environmental conditions, longer life batteries, specific applications, etc.).
Standardization processes will be also impacted by the adoption of commercial standards in PPDR. Standardization of PMR and commercial systems has traditionally followed loosely coupled processes, which have evolved at very different paces. Adoption of LTE related standards within the PPDR community could change this situation and turn into a common, interoperable standard evolution process. Indeed, PPDR community, which has witnessed over the years how a standard solution for data communications (e.g. TETRA Enhanced Data Service [TEDS]) has not been able to come to a reality, will take advantage of the advances achieved in 3GPP since 2004, when LTE started its standardization process.
Within such a common standardization framework, PPDR community would keep synchronized with technological improvements pushed from the commercial domain. Furthermore, the PPDR community would be in position to promote the development of specific capabilities intended to extent the standard to better address PPDR requirements (e.g. support of fall-back mode operation, multicast capabilities for more efficient group call support, etc.). The growing interest towards the public safety sector, which in the current economic and competitive climate is seen as a potential and interesting source of revenue for manufacturers, can facilitate the development of the necessary standardization activities (e.g. back-to-back mode in LTE).
Access to PPDR services through commercial PMNs will impact on the building processes of both dedicated PSNs and PMNs. As long as commercial networks are considered to play an important role for PPDR service delivery, building processes of PMN infrastructures can be impacted by government efforts (e.g. public funding) intended to improve the commercial networks coverage (e.g. better coverage of rural areas), robustness and reliability, as alternative to the exclusively building out of private infrastructures. On the other side, the design and deployment of dedicated PSN infrastructures might consider the existence of commercial networks that can be used to complement/extent the coverage and capacity of any additional dedicated infrastructure. Besides, the support of roaming services to PPDR users between PSNs and PMNs also impacts on the building of both types of communication systems that will have to add support for the required roaming interfaces and interconnection facilities (e.g. interconnection links and gateways). The use of both PSN and PMN for PPDR service delivery is also expected to introduce important changes on sharing processes. Hence, infrastructure-sharing practices followed by network operators within the commercial domain (e.g. RAN sharing) can now also involve PPDR systems (e.g. sharing sites and backhaul communications equipment with commercial providers is being actually considered by the FCC for the deployment of the nationwide PPDR network).

B. Management of priority access
Priority access for PPDR traffic over commercial PMNs will impact on the building processes of these networks. Hence, PMNs will have to support the required prioritization functions and capabilities to ensure guaranteed availability of some predefined amount of capacity for PPDR use in periods of high network load and during disaster conditions. Support of these features will impact on the operations and management processes of PMNs. The activation of priority access in an emergency response can reduce the amount of capacity available to support citizen’s traffic in a moment that basic mobile communications services are most valuable to citizens. Addition of specific clauses in customers’ contracts to describe the level of service degradation in emergency conditions might be required. Also, considering that PMN users have the right of reimbursement due to service interruption, some modifications would be needed to consider some exceptions to this right in emergency situations.
Support for remote control by PPDR users of priority access policies enforced in PMNs will also impact on the building, operations and management processes of PMNs. In particular, the considered remote control of priority access requires PMNs to support specific roaming configurations for PPDR traffic (i.e. home routed roaming configuration in front of local-breakout roaming configuration, see [24]). Besides, technical harmonization of the parameters needed for prioritisation management is needed among commercial operators and PPDR users. This means that agreements (e.g. Service Level Agreements) have to be negotiated between PPDR and MNOs to settle a number of technical design decisions to ensure that the QoS PPDR users experience is consistent among networks.
Support of prioritization capabilities also impacts on producing processes of infrastructure equipment as long as some of the underlying capabilities are optional for commercial use but necessary when the operator is committed to provide priority access. As well, the support of human intervention in priority decisions requires the development of additional functionality to provide situation-specific information that the network cannot detect on its own. This additional functionality would mainly consist of new software and related Application Programming Interfaces (APIs) used to export the management of the prioritization services to control rooms. Standardisation processes can also be impacted to address the specification of required APIs for prioritization management.
Regulatory bodies might be required to establish a proper regulatory framework to define the legal obligations of MNOs as to the support of priority access as well as the measures that can be applied to offset possible economic impacts on a network operator providing priority access. The support of priority access in commercial networks can be established either by law or as additional pay service offered by MNOs that charge additional costs to interested users.

C. Dynamic spectrum management
The adoption of a solution based on dynamic transfer of exclusive rights of use requires new processes to be established to lease the spectrum from the spectrum license owner to the other users. Currently, this possibility is allowed by regulations as described in the May 2011 report issued by the CEPT [28]. In fact two European countries, Denmark and Switzerland, allow spectrum trading for emergency service even if the network infrastructure and equipment may not allow it from a technical point of view. The same report indicated that out of the 22 countries that responded, only four declared that spectrum trading is not allowed.
Secondary access for PPDR users can be implemented in two ways: a) the PPDR user can be the secondary user of a primary service like Digital TV and b) the PPDR user can be the spectrum licensee and primary user, while another radio service can be the secondary. New processes and regulations must be established to allow secondary access for licensed PPDR spectrum (option b). On the other hand, option a) is already defined in USA for TV white spaces. New processes must also be defined in PPDR organizations for secondary spectrum access, which is rather new for PPDR organizations, which have always used dedicated spectrum for their operational needs.

D. Dynamic coverage and capacity management
Solutions for coverage management require localisation information that can be provided by the devices themselves or obtained from the networks based on available parameters analysis. The first approach requires localisation modules embedded in terminals, what impacts terminals, whereas the second approach implementation is a software solution only and impacts network infrastructure production process. Beside processes related to the solution implementation, it also impacts daily basis network operations by automation works related to network coverage quality assessment.
Network coverage management performed by means of antenna tilt and transmission power readjustments require remote control antenna systems and power amplifiers able to operate at high power levels. Raising amplifiers operating power impacts infrastructure elements production process whereas remotely controlled antenna systems only buying process (remotely controlled antennas are available at the market).
Network coverage and capacity management performed by means of base station and relay node deployment in field, impact infrastructure producing process due to specifications related with methods of their use for PPDR purposes (e.g. shall be designed as a mobile units, simply to deploy, etc.). Due to all advantages and disadvantages of these network elements’ specifications, they should not be utilised permanently in one area but deployed on demand according to temporary needs in areas of e.g. accident or concerts. Having in stock these elements and use them from time to time only might not be desired from a MNO’s economic point of view. Thus a new renting process can be added to infrastructure acquiring processes. With this process, a MNO would only rent the amount of network elements required in certain situation, instead of retaining them all time.
Both load balancing and inter cell interference coordination mechanism are assumed to be utilised in order to improve PMN capacity for PPDR purposes and both are software solutions. Thus implementation of these network capacity management functionalities should impact only network infrastructure production process.
With regard to roles, a new role of infrastructure renter is created as a result of the new renting process. Renter role might be held by a business entity that commercially rents infrastructure equipment to MNOs on occasion of events that require additional coverage or capacity or by local authority or PS service that make this equipment accessible to PMN only for PPDR purposes.

Potential Impact:
While Project HELP proposed solutions are technically possible, their adoption is dependent on the political support by European governments. Depending on the level of political support, the evolution of PPDR communications can be faster or slower. Therefore, the roadmap for the realisation of Project HELP solution requires a consensus building process with relevant stakeholders including e.g. PPDR users, networks operators and manufacturers. In this respect, during the execution of Project HELP a coherent strategy for dissemination and networking has been designed and executed. Project HELP dissemination plan has been strongly committed towards the achievement of a qualified wide awareness of the diverse stakeholders in public safety. Figure 12 illustrates the main dimensions that allow categorising Project HELP’s dissemination actions. Achievements are described in the following.

1.- UAB and OAB
One important aspect in the strategy defined by Project HELP in order to achieve its objectives has been the establishment of a User Advisory Board (UAB) and an Operator Advisory Board (OAB). They have provided to the project the end user and market perspectives, as it is further described in the following. At the same time, the experts forming UAB and OAB have had early access to concepts and ideas around network sharing and spectrum sharing in public safety scenarios as developed in Project HELP and, therefore, this has contributed to create awareness and disseminate our work in these expert fora.
The UAB has been established to validate reference operational scenarios, user requirements and system requirements. The UAB has been coordinated by BAPCO and has consisted of a number of representatives from public safety and emergency service organisations throughout Europe. The size of the group is claimed as a good trade-off figure, providing wide representation while preserving operability and efficiency in the work. UAB members in Project HELP are reflected in Table 4.
The OAB has been established to validate the envisioned system concept and solution framework. OAB has also brought high value in identifying incentives motivating operators to participate in the solution, which is a key factor from the point of view of future implementation. Besides, operators’ business oriented views have enriched the ideas generated during techno-economic studies on a very early stage, increasing the efficiency of the work. The OAB has consisted of a number of mobile network operators across Europe (see Table 5).

2.- Project HELP’s Workshops
Project HELP scheduled two workshops: the first in M9 (October 2011) and the second in M14 (March 2012) of the project. The workshops have been aimed at providing an independent validation process and fostering the dissemination of the project objectives and developments. Questionnaires have been distributed during the workshops to request feedback to the participants. A report has been created at the end of each workshop to collect the feedback and conclusions [38][39].
The theme of the Workshop #1 was “Networks and Experimental Platforms for Interoperable and Efficient Public Safety Communications”. It was held at the facilities of the Joint Research Centre of the European Commission in Ispra (Italy) on the 10th and 11th October 2011. The Workshop was organised in collaboration with the CELTIC project Federated Test-bed for Public Safety communication (FT-PSC). Workshop #1 also provided the opportunity for the OAB to have a face-to-face meeting in a separate room to discuss specific operational and technical challenges for the deployment of network and spectrum sharing solutions with telecom providers.
Workshop #2 was held during the 14th Annual British APCO Exhibition & Conference at Manchester Central on the 17th of April 2012. Similar to the first Workshop, this second event was also aimed at providing an independent validation process and fostering the dissemination of the project objectives and developments with representatives from end-users, regulatory, industry and research entities – focussing on the evaluations of the outcomes of the Project HELP.

3.- Standardisation
Project HELP has achieved a significant impact to the standardisation activity in ETSI Technical Committee on Reconfigurable Radio Systems (ETSI TC RRS), which is responsible for investigating and standardise reconfigurable radio technologies like Software Defined Radio (SDR) and Cognitive Radio (CR). Within TC RRS, Working Group 4 (WG4) specifically focuses on Public Safety, which addresses aspects such as:
• Investigate spectrum sharing of Public Safety networks with commercial or military networks.
• Investigate the feasibility of multi-standards terminals for Public Safety both with the commercial domain and the military domain.
• Define business models to support the “case” for SDR and CR in the Public Safety domain.
• Investigate/reuse security concepts between WG4 and the other WGs in ETSI TC RRS.
• Investigate CR extensions of TETRA in collaboration with ETSI TC TETRA.
Very fruitful interactions have been achieved with ETSI TC RRS. Supported by all the Project HELP members who are ETSI members (i.e. CAS, BAPCO, JRC and UPC), a new Work Item (WI) was adopted by ETSI RRS WG4 at the ETSI RRS#14 meeting held in Aachen (Germany) on 11th-12th May 2011. The title of the WI is “Use Cases for spectrum and network usage among Public Safety, Commercial or Military”. The WI is associated to ETSI Technical Report (TR) 102 970.
In addition to ETSI TC RRS, other actions have been undertaken:
• Project HELP, through JRC, has participated to the meetings of the new CEPT Project team FM49, which is focused on the provision of broadband connectivity for PPDR. The JRC participated to the Kick-Off Meeting (KOM) of CEPT FM49 in September 2011, which has the responsibility to work on radio spectrum issues concerning PPDR applications and scenarios, in particular concerning the broadband high speed communications as requested by PPDR organisations. At the KOM of CEPT FM49, JRC provided an overview of the work done in Project HELP and the related ETSI TR 102 970.
• The relevant agencies and DGs of the European Commission (ENTR, INFSO) have also been informed on the progress of Project HELP through common meetings and workshops including the SDR standardization workshop organized by DG ENTR, EDA and the JRC on November 2011, which is instrumental for the definition of a mandate on SDR/CR standardization. The topic of spectrum sharing is mapped to Objective C of the mandate.

4.- Contacts and Links
The project has established relationships with a number of relevant organizations at European level. In particular, JRC, which as a DG of the European Commission, has established links with the other DGs, which may be interested to the results of the Project HELP. Also, the participation to different networking events has provided good opportunities to disseminate the work and ideas of Project HELP. In this respect, several actions and achievements can be listed:
• Related to Public Safety Communications Europe (PSCE) [40], its Secretariat was informed by the Project Manager about the start and scope of Project HELP in March 2011. A description of Project HELP was posted on the section related to EU projects of PSCE website in April 2011 and Project HELP was reported in a PSCE Newsletter (nº 2, 2011).
• Continuing with PSCE, Project HELP was invited to a presentation at the PSCE Conference held on 30th November and 1st December 2011 in Warsaw, Poland. The conference had a focus on interoperability and enhanced communication networks. Szymon Stefanski (DATAX) attended the event and made the presentation on behalf of Project HELP.
• Several Commission services (namely DG INFSO, HOME, ECHO and ENTR) jointly organised the Workshop “The future of PPDR services in Europe”. The goal of the workshop was to better understand the level of national commitments regarding public safety and security tasks, which require high-speed mobile communications (broadband). The desirable outcome of the workshop should be that stakeholders in public safety and security became aware of national plans or commitments that could lead to similar functional requirements, opportunities to cooperate and pool resources (especially manpower, finance, equipment and radio frequencies) and a strengthening of the single market for PPDR equipment and cross-border operation. The Workshop “The future of PPDR services in Europe” was held on 30th March 2011 in Brussels. Gianmarco Baldini (JRC) and Ramon Ferrús (UPC) attended the event.
• The 13th BAPCO Annual Conference (BAPCO 2011) was held in London on the 13th and 14th of April 2011. The theme of the conference was ‘Delivering Lower Cost Incident Management through Technology’. BAPCO annual conference is a must-attend event for all professionals engaged in the provision and use of communications and information management technologies for civil contingency, public safety, business continuity and information management. The two-day event featured a comprehensive conference programme and exhibition, offering a wealth of networking and learning opportunities for attendees, and a unique opportunity to see and access the latest technologies that are to shape the future of the industry. Paul Hirst (BAPCO) attended the event.
• The European Commission (DG Enterprise and Industry) organised on the 26th of May 2011 a meeting with experts to discuss Software Defined Radio (SDR) and Public Protection and Disaster Relief (PPDR) Radio-Communications with the aim of assessing the feasibility of hybrid Military / Public Safety standards for SDR. It was a technical meeting with a limited number of relevant participants and not a workshop to present projects. Oriol Sallent (UPC) attended the meeting on behalf of Project HELP.
• Workshop on Software Defined Radio and Cognitive Radio standardization (Ispra, 17th – 18th November 2011) organised by European Commission Joint Research Centre. Software Defined Radio (SDR) and Cognitive Radio (CR) are expected to become important drivers for the evolution of wireless communications and to bring along substantial benefits: from reconfigurable flexible and cost-effective architectures for wireless devices to a better utilization of the radio frequency spectrum which helps to mitigate the “spectrum scarcity” problem. The purpose of this workshop was to identify the main steps needed to drive the development and use of SDR and CR technologies in Europe, including the elements of a future standardization mandate as well as related regulatory and certification issues, and to define a roadmap to that purpose. Project HELP was invited to the Workshop. O. Sallent (UPC) gave the presentation.
• On the 25th January 2012 there was the FP7 Security Research Workshop entitled “Toward a demonstration programme on crisis and disaster management”. O. Sallent (UPC) was invited to the event and travelled to Brussels to attend the Workshop.
• The phase I project ACRIMAS organised its final event on Thursday, 19th April 2012, at the Hotel Mercure Brussels Center Louise in Brussels. O. Sallent (UPC) was invited to and attended the event.
• The phase I project CRISYS organised its final conference on Thursday, 10th May 2012 in Barcelona. O. Sallent (UPC) was invited to and attended the event.
5.- Publications
Publications of high quality project results in international peer reviewed journals, magazines and book chapters have been envisaged. The dissemination plan has met top-down (PCC) and bottom-up (partners and WPs) perspectives and has been developed in a continuous incremental (iterative loop) process. The dissemination has allowed multi-partners co-authorships and to develop excellent quality/multiple skills papers, considering both Project HELP (and WPs) interests and partners specific interests/ambitions. The dissemination intentions have been discussed inside the WPs (meetings, phone conferences) and WPLs and partners have provided continuous inputs/updates.
A publication has been achieved at the IEEE Vehicular Technology Magazine - Special Issue on “Applications of Cognitive Radio Networks”. The objective of this special issue was to address Cognitive Radio (CR) networks from an application-oriented perspective, contributing to the exploitation of CR concepts and associated techniques driving them towards practical applications and scenarios of use. In this context, this special issue targeted the identification, development and assessment of novel as well as existing applications exploiting the CR concept. Given that the Special Issue explicitly included the item “Cognitive Radio for emergency and public safety applications”, the paper entitled “Enhancing Public Safety Communications through Cognitive Radio and Spectrum Sharing Principles” and co-authored by R. Ferrús (UPC), O. Sallent (UPC), G. Baldini (JRC) and L. Goratti (JRC) was prepared and submitted for review by 30/09/11. The paper has been accepted and published in June 2012 issue [41]. The Journal Impact Factor (Journal Citations Report 2010 – Telecommunications) is 1.184 and it is ranked 22/80.
The journal paper “The Evolution of ICT in the Public Safety domain: Challenges and Opportunities” co-authored by Gianmarco Baldini, Christian Wietfeld, Sebastian Subik and Oriol Sallent has been published on the International Journal of Disaster Recovery and Business Continuity [42]. The focus of the paper is to describe the evolution of ICT in Public Safety domain at different levels from the wireless communication layer to the application and services layer.
Additionally, some more journal papers are currently in preparation. On one side, a paper describing the definition of the operational scenario used in Project HELP and how spectrum sharing can improve the performance of the first time responders will be submitted to the journal Disaster Prevention and Management. On the other side, an article describing the key aspects of the Project HELP solution framework for the provision of PPDR services considering the involvement of LTE-based dedicated PS as well as commercial mobile networks will be submitted to IEEE Communications Magazine (with a Journal Impact Factor of 2.837 and ranked 04/80 in 2010). This article is intended to discuss on the suitability of LTE and related technologies for PPDR service provisioning, describe Project HELP envisioned system view for future PPDR networks encompassing commercial and dedicated networks, provide a description of the overall system architecture and point out some key considerations on spectrum related issues that are central to the proposed PPDR service provisioning solution.
Finally, it is worth noting that Project HELP has triggered the Special Issue on “Visions on the future Public Safety communications” at the IEEE Vehicular Technology Magazine. This special issue looks for tutorial-nature papers that reflect visions for the medium/long term evolution of PPDR networks. Papers covering a variety of technical challenges, as well as multidisciplinary papers that consider the policy and user-adoption/operational challenges of moving legacy PPDR communications toward next generation PPDR systems are solicited. Important dates are: manuscript submission due on 30th September 2012, acceptance notification by 15th January 2012 and publication in June 2013. The Guest Editors are: Oriol Sallent (Universitat Politècnica de Catalunya, William Lehr (Massachusetts Institute of Technology), Cédric Demeure (Thales Communications & Security) and Gianmarco Baldini (JRC – European Commission).

6. -Project HELP leaflet
A leaflet was produced as a means to distribute general information about the project in different relevant fora to increase the level of awareness about Project HELP.

7.- Public Website
The Project HELP website (http://www.fp7-sec-help.eu) was launched in early February 2011. The website has been regularly updated with the latest achievements and related relevant news and events. The document management platform of Project HELP is accessible from the Project HELP website front page (requires partners’ Login). In order to promote the Project HELP’s website with useful information, dissemination opportunities have been advertised through the public website. Conference calendar appears as a permanent entry under the Events section.

8.- Roadmap for the realisation of Project HELP solution
From a purely technical point of view [25], Project HELP system architecture solution could be readily implementable in the short/medium term, since the proposed solutions rely at a great extent on current standards. From an economical point of view [15], Project HELP solution would have an impact on the market structure, business models, role of key players, etc. Furthermore, the future of PPDR communications will also be strongly influenced by political decisions. Therefore, the roadmap for the realisation of Project HELP solution requires a consensus building process with relevant stakeholders including e.g. PPDR users, networks operators and manufacturers.
The work programme of the Security theme [26] offers a unique opportunity to stimulate cooperation and, therefore, it constitutes the pivotal point in the roadmap for the exploitation of Project HELP results. Besides, Project HELP roadmap also includes several actions in standardisation and regulation frameworks that will be conducted in order to promote the aforementioned consensus and to continue the exploitation of results by means of contributing to existing work items or proposing the creation of new ones. These elements of the roadmap are further elaborated in the following subsections.
A. Security research: FP7-SEC-2013-1
Under its wider R&D budget for 2007-2013 – known as the Seventh Framework Programme for Research (FP7) – the EU is investing EUR 1.4 billion for security research. An overview of all projects currently supported by FP7’s Security Research budget as of July 2011 is given in [27]. Some key considerations about the research projects closer to Project HELP activities are provided in the Annex of this deliverable.
Project HELP was formulated as a Coordination and Support Action (CSA) in the “Topic SEC-2010.4.1-1 Aftermath crisis management - phase I” under “Activity: 10.4 Restoring security and safety in case of crisis” of the Security Work Programme 2010 [27]. As stated in the Work Programme 2010, Topic SEC-2010.4.1-1 was conceived as the initial phase (Phase I) of a full demonstration programme (phase II, which will build upon phase I) aimed at “demonstrating an integrated and scalable crisis management system capable of providing comprehensive situational awareness to decision makers to ensure a timely, co-ordinated and effective response to large scale disasters, including natural disasters (floods, earthquakes etc) both inside and outside Europe”. Within this mission area on restoring security and safety in case of crisis, Project HELP objectives were also connected to “Activity: 10.5 Improving security systems integration, interconnectivity and interoperability” of the Security Work Programme 2010 [27].
On this basis, Phase II demonstration programme within the FP7 2013 Work Programme in the area of Security [26] is the natural framework for the exploitation of Project HELP results by developing specific solutions and assessing their performance and experimental validation.

Phase II demonstration programme
The paper “Orientation paper prepared in connection with the FP7 2013 Work Programme in the area of Security” dated on 17th April 2012 was made public at an early stage in the adoption process of the work programme to provide potential applicants with the currently expected main lines of the 2013 work programme [26]. It is a working document not yet endorsed by the Commission and its content does not in any way prejudge the subsequent modifications by the Commission, nor the final decision of the Commission. The final adoption and the publication of the work programme by the Commission are expected in mid-July 2012.
It includes the Topic SEC-2013.4.1-1 Phase II demonstration programme on aftermath crisis management.
The Phase II demonstration programme will provide an integrated framework bringing together the abilities of industry, research institutions, operational end-users and the citizens, to jointly progress in the critical areas of crisis management and to create acceptance for new solutions and approaches. It will therefore help crisis management systems and cross border concepts to adapt to new and changing threats and to the use of new tools.
Although it is impossible to foresee all potential disasters and their effects, the demo is expected to provide solutions (either generic tools or a coordinated portfolio of tools) that can be used on a daily basis by end-users, but that are also scalable in a crisis and adaptable to different crisis situations as well as changing conditions during the disaster.
In this broad context, interoperable secure communication systems are crucial to support operational tasks in aftermath crisis management. This is clearly backed by the fact that:
• High-speed data services are increasingly important to support PPDR operations and applications.
• An evolution of PPDR communication networks is needed to satisfy a growing demand for high-speed data services.
The technical solutions proposed by Project HELP can be integrated in a future overarching organisational and procedural framework, which is an evolution of existing frameworks. As with other technologies used in the PPDR domain (e.g. decision support, GIS), telecommunications are used to support the operational capabilities of PPDR users and they should not be a service on its own. As a consequence, it is important to analyse what modifications to existing process or organisations structures are needed to use these technical solutions.
Project HELP firmly believes that the conception and development of a European Crisis Management operational framework should not be decoupled from the evolution of PPDR communications capabilities. On the one hand, operational procedures for crisis management should establish requirements on expected PPDR communications capabilities. On the other hand, advanced PPDR communications system capabilities can improve/modify working practices. To this end, results and expertise from Project HELP can contribute to build a comprehensive, consistent and upmost efficient European Crisis Management operational framework with the ultimate goal of achieving a synergic operation of existing infrastructures to satisfy coverage and capacity needs for operational tasks, as Figure 13 depicts.

B. ETSI TC RRS
ETSI TR 102 970 is expected to be finalised in September 2012. Even though this is beyond the life-cycle of Project HELP, partners are committed to continue contributions and to support the successful achievement of this WI. Besides ETSI TC RRS, network and spectrum sharing solutions should be promoted to other fora for the definition of appropriate standards.

C. CEPT FM49
Project Team FM 49 within CEPT ECC on “Radio Spectrum for Public Protection and Disaster Relief” is targeted to identify and evaluate suitable bands for European-wide harmonisation of spectrum (both below and above 1 GHz), by taking into account cross-border-communication issues and PPDR application requirements.
The planned outcomes of CEPT FM 49 are:
• End of 2012: ECC Report to consolidate broadband PPDR user requirements.
• End of 2013: ECC Report addressing the development of a European harmonised regulatory framework for broadband PPDR to maximise interoperability (frequency bands, technology aspects, use of dedicated/public/hybrid networks).
• Mid of 2014: A new ECC Decision or amended ECC/DEC/(08)05.
Project HELP, through JRC, has participated to the meetings of CEPT FM49. At the kick-off meeting of CEPT FM49 in September 2011, JRC provided an overview of the work done in Project HELP and the related ETSI TR 102 970.
Project HELP plans to promote a presentation at FM49, in order to raise awareness, stimulate discussion and present the proposed solution in terms of spectrum sharing as well as network sharing mechanisms.

Project HELP logo is depicted in Figure 14.

Contacts list:
- Oriol Sallent (sallent@tsc.upc.edu) Universitat Politècnica de Catalunya (Coordinator)
- Gianmarco Baldini (gianmarco.baldini@jrc.ec.europa.eu) JRC – Joint Research Centre – European Commission
- Serge Delmas (serge.delmas@cassidian.com) Cassidian SAS
- Paul Hirst (euprojects@bapco.org.uk) BAPCO LBG
- Rafal Pisz (rafal.pisz@datax.pl) DataX Sp. z o.o.