In a recent study from the Emergency Services College of Finland, Markku Rantama and Kari Junttila analysed the forces behind the evolution of radio data communication in Finland’s fire and rescue services. In this article Markku Rantama outlines their findings

In Finland, the work of the fire and rescue services today is closely tied to the national mission-critical TETRA radio network, VIRVE (VIRanomaisVErkko means Authority Network). The diagram above illustrates the process of evolution through which the service is now passing, and introduces some of the key terms used in this article.

An Emergency Response Centre (ERC) sends emergency information with task-related data to fire and rescue resources by means of status and SDS messages. When necessary, resources which are not equipped with TETRA radios can be contacted via SMS over commercial mobile networks. Alerted persons acknowledge the messages received and send their status information back to the ERC by status messages.

But the most important and valuable communication channel is TETRA’s group call capability. Through this, task-related additional information from the ERC is simultaneously conveyed to all resources. It is used also for communication across authority boundaries among officers on similar duties and responding to larger incidents.
SDS and status messages are also used for the ERCs’ transaction handling system and the command and control systems of the fire and rescue services.

The main bottleneck in TETRA data transmission is its modest transmission rate: when a single timeslot is used, data rates vary in practice between 2?kbit/s and 4?kbit/s. SDS-based data is sufficient for short status and location information messages and even for image delivery tailored for the small screens of handportables – but it will not be enough to meet future requirements for high-resolution still pictures, large files, video streaming and other multimedia content.

Because of VIRVE’s limited data transmission throughput, many regional fire and rescue service departments have been experimenting with – and have even deployed – data services supplied by commercial mobile networks (2G/3G and @450) for purposes such as video transmission and Internet browsing. A serious problem with these services is that they are not designed or deployed to suit the demands of mission-critical communication. When most needed (in times of disaster or crisis) they may be unavailable because of their lack of resilience or heavy usage by the general public.

Meanwhile, Finland’s regional fire and rescue service departments are deploying secure IP access (PeIP) into the security network of the state authority. By using PeIP, they can access services reserved for public bodies and in addition they can communicate securely among themselves.

Evolution process

Factors and forces driving change are users’ needs, the reconfiguration of ERCs, technological evolution and – especially – the evolution of mission-critical communications, a process which will depend on the allocation and harmonization of suitable spectrum for broadband data.

In planning the modernization of functions, processes and the ICT systems supporting them, users’ needs are always the starting point. In the fire and rescue services, future communication needs have been explored by conducting interviews, queries and workshops. These needs have been documented by a multi-authority development project called KEJO, which resulted in a requirement specification for multi-authority command and control system to be used in the field.

Data communication needs can be classified according to the data rates required (see table, previous page). At present, the speech and narrowband data services of VIRVE are adequate. But mission-critical wideband and broadband services are not available, and are being substituted by other, non-mission critical services. In the near future, the possible adoption of wideband TEDS will improve the situation, but broadband data will be missing from VIRVE for many years to come.

A rearrangement of ERCs during the period 2010–2015 will combine the present 15 operational areas in Finland into just six (see map, above). Aims of this rearrangement are networked and uniform working processes, uniform information and control systems and better handling of overload situations. The change has also created a need to redefine talk groups and to renew the identification system for field units. These developments are already under way.

Technological evolution has been rapid in recent years and has brought new possibilities to wireless data communication. Commercial mobile networks have evolved through 2G (GSM/GPRS/EDGE) and 3G (WCDMA/HSPA/HSPA+) to 4G networks (LTE/LTE-A), the first of which are being deployed right now. Data rates have advanced from narrowband into broadband, enabling multimedia services with maximum transmission rates of up to several hundreds of megabits per second. But it remains a serious drawback of these networks that their usability and availability in massive emergency situations cannot be assured.
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