Wireless LAN will have a role as an internal bus within vehicles and also in data transmission between vehicles and the fire station. Also, next-generation CCC systems could have functionalities such as a local WLAN network at the 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 field 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 classified so that terminal units, field command and control applications and transmission networks manage priorities. Classification must be dynamic – adapting, for example, to the current operational status or location.
(中國集群通信網(wǎng) | 責任編輯：陳曉亮) |
