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futures


critical IP data, status and SDS messages and would ensure the quality of speech services during periods of network congestion. Nonetheless, broadband data services based


on VIRVE are far in the future and there is no guarantee that they will ever exist. T is is why


dedicated broadband data services for safety and security authorities will be needed in the near future. Today it is necessary to use commercial mobile networks, even though they are not intended for critical communication.


T e complete 200-page study, in Finnish only, can be downloaded from the web site of the Emergency Services College of Finland at www.pelastusopisto.fi in the Information section. Its fi lename is Pelti loppuraportti liitteineen.pdf


Public safety communication in Finland: a bouquet of bearers Services, registers


Public packet network


Radiocommunication interfaces used by Finland’s fi re and rescue athorities:


A: air interface between TETRA network and handportable terminal


Authority packet network


3G/4G/WiMAX D A B


VIRVE (TETRA)


C F


D: air interface with commercial mobile networks (3G/4G/WiMAX)


E: two-way satellite connection


F: WLAN interface between rescue unit and network at fi re station


Fireman Rescue unit


Commercial mobile networks (3G/ HSPA) and emerging fourth-generation wireless networks (4G/LTE/WiMAX) offer high transmission rates which allow multimedia services to be built upon them. In Finland, the 3G networks of all operators provide coverage almost countrywide, and the fi rst 4G services are being introduced to the most densely populated areas.


Also used by Finland’s public authorities is the countrywide @450 network. But its future is currently under speculation, because the network operator has recently changed and the technology used (Flash-OFDM) has become obsolete with no future support. The main advantage of this network is its frequency band (450 MHz), which permits wide coverage at reasonable infastructure cost. However, future use of the @450 network for public authority communications will depend on the future plans of the operator, including the selection of new radio technology.


Wireless LAN will have a role as an internal bus within vehicles and also in data transmission between vehicles and the fi re station. Also, next-generation CCC systems could have functionalities such as a local WLAN network at the


Issue 3 May 2011 TE TRA TODAY Fire station


incident scene. All units or services could join the same virtual local network. This would minimize the load on the air interface of the mission-critical communication system. However, there is a risk that the unlicensed WLAN spectrum might become congested because of nearby consumer hotspots, especially in densely populated areas. Licensed bands for the public authorities might provide a solution.


Satellite-based broadband services are of value when no other bearer services are available. They are especially useful for stationary units e.g. on remote locations, at sea or during storm disasters, when all other networks are down. Their usability in mobile operations is close to none, because of the need to accurately track the satellite.


TUVE: this nationwide, secure IP-based transmission backbone for Finland’s public safety and security authorities will provide a core for mission-critical communication.


Multi-bearer service or capability: a unit can select the best bearer service to use, taking into account the current operational status, the size and priority of information elements to be conveyed and the state of all supported radio


channels. No user intervention should be needed. In practice, support for desired bearers will be provided by multi-bearer routers.


Mobile awareness is the ability of fi eld command and control systems to be aware of the present state of supported bearer services and to adapt itself and data transmission according to that. In extreme situations this can mean that operation must not freeze even if bearers are unavailable or too congested for a while. Buffering, compression and prioritization of messages are some means to survive in abnormal situations. Obviously, a separate preparedness plan for these cases must exist.


Prioritization can be used when the available data transmission capacity is less than is wanted. This can happen in overload situations, whether because of failures or too many users under the same base station. Functional processes, messages and their information elements must therefore classifi ed so that terminal units, fi eld command and control applications and transmission networks manage priorities. Classifi cation must be dynamic – adapting, for example, to the current operational status or location.


31 E


B: air interface between TETRA network and vehicle radio/modem


C: air interface between TETRA network and fi xed radio/modem


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