The current status of existing PPDR communication networks deployed in EC member states is not clear. The challenge is to gather reliable statistical data and user requirements for future PPDR communication networks to understand varying requirements and to identify use cases in order to establish common solutions for interoperability with legacy TETRA / TETRAPOL networks and support the migration towards next generation PPDR communication networks.
The landscape of available standards and products for next generation PPDR communication networks is not clear at this moment. The challenge here is to select the technology that is most suitable for PPDR applications. Broadband networks on basis of CDMA, WiMAX and LTE are now available, and being prepared to support mission-critical requirements of PPDR agencies. Even mission-critical TETRA Enhanced Data Services (TEDS) network extensions may be considered, although TEDS offers insufficient data throughput for most advanced services like video streaming or document transfer. The emerging LTE (Long Term Evolution) technology seems to be the definite answer to this challenge. PPDR agencies in the US have already adopted LTE as the preferred next-generation communication technology for private PPDR networks, as well as to use commercial LTE operator services with proper QoS whenever private networks are regionally not available or feasible.
The challenge of selecting the right deployment option is very relevant to PPDR organisation considering the three reference scenarios that were presented in section 1.1.2. Although commercial operators could offer Quality of Service and typical PMR features on their networks, the performance, security and resilience of networks must comply with PPDR requirements, especially during incidents, crisis and disasters. The Total Cost of Ownership (TCO) needs to be considered as well for private versus public networks.
The demanding requirements of PPDR agencies for mission-critical voice and broadband services cannot be served by existing 3G and 4G standards alone. The challenge here is whether common requirements and resulting extensions of standards and / or solutions can be defined that create enough economy of scale which is interesting enough for manufacturers and operators and thus supporting the business case of developing products and services. Solutions should be both compliant with user requirements and cost-effective in terms of Total Cost of Ownership, creating the need for open solutions.
Regarding spectrum requirements, PPDR organisations face the challenge of different interests within EC countries whether or not spectrum must be reserved for PPDR applications. For some countries the revenue of spectrum auctions is most tempting, while for other countries the increased safety and security offered by well-equipped PPDR agencies is most important. PPDR users and industry within the Public Safety Communications – Europe (PSCE) forum are now coordinating the efforts to at least reserve a part of the free spectrum enabled by Digital TV services [PSCE2], similar to the situation in the US. Refarming of spectrum around 400MHz could also provide opportunities for LTE based PPDR networks with the additional benefit of improved propagation, possible use of higher output power and the ability to re-use existing site facilities.
PPDR agencies require a high degree of security and reliability for their communication needs, supporting complex scenarios which involve interoperability between different PPDR networks and systems, including cross-border communications. The challenge here is to identify security mechanisms that can be adapted to work on both private and public mobile broadband networks, offering seamless mobility (roaming), end-to-end security and privacy, as well as protection against intrusion, in order to meet PPDR user requirements.
The expectations of next generation PPDR communication networks are very high. They should enable the deployment of an all-IP architecture for PPDR organisations, supporting mission-critical voice and broadband data services. The challenge is whether emerging standards and products for next generation wireless networks can satisfy the requirements of PPDR agencies, while these were developed with consumer requirements in mind. Existing Push-to-talk (PTT)-over-Cellular (PoC) services are certainly not suitable for PPDR applications, while these were designed for consumer and business “Walky-Talky” type of operation. The absence of PTT buttons on all modern smartphones after being available on most feature phones during the 2005-2008 time frame is a worrying trend. Very recently, consumers are now using free or low-cost “apps” such as WhatsApp, Ping, Skype and Facetime on their smartphones instead of IMS-based Short Message Services (SMS), conferencing and video calling services. These trends should be investigated to see how they pose threats to the adoption of standards, and could create opportunities at the same time.
On the positive side, the fast development of smartphone and tablet technology provides unique opportunities for PPDR users to benefit from. The challenge is to include advanced features in products that are suitable for PPDR users. There is a strong belief that PPDR agencies can benefit from modern communication concepts such as instant messaging, picture sharing and video calling. However, the fit-for-purpose criterion is very important for PPDR users. Consumer phones and tablets are not robust enough to withstand extreme physical and environmental conditions. Dedicated terminals should be developed on basis of Commercial Off-The-Shelf (COTS) components, with more robust enclosures, more stable software and special attention to security threats. Innovations such as user-friendly operating systems, multi-touch enabled screens and the concept of downloadable apps are now becoming the norm, and should thus also be available for PPDR terminals. The challenge here is to create an ecosystem that supports the development of mobile equipment by a multitude of suppliers on basis of open standards, similar to the situation that made TETRA a success in the previous decade.