Towards a Baltic Sea Region Strategy in Critical ... - Helsinki.fi

CHAPTER III: INFORMATION AND COMMUNICATION TECHNOLOGY
To further compound the crises, we assume that some of BSs are damaged as part
of the common-cause failures resulting from a hurricane. This means that a larger
number of users called in to respond to the crises have to perform their duties
using relatively fewer network resources than those available under normal
conditions.
Figure III—23 Available base stations under normal and crisis conditions.
If one BS is lost in a hurricane, the number of calls being queued for more than
10s under crisis management increases to 2%. However, if two BSs are lost during
the crisis, the latter figure rises to over 8%, whereby, only 82% of queues can be
setup within the 0.5s limit. This implies that the higher the level of disruption of
the infrastructure, the more the need for stringent crisis management.
Figure III—24 TETRA system performance under crisis management in various levels of
infrastructure disruption.
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