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Security Monitoring

Security monitoring networks are composed of nodes that are placed at fixed locations throughout
an environment that continually monitor one or more sensors to detect an abnormality. A key
difference between security monitoring and environmental monitoring is that security networks are
not actually collecting any data. This has a significant impact on the optimal network architecture.
Each node has to frequently check the status of its sensors but it only has to transmit a data report
when there is a security violation. The immediate and reliable communication of alarm messages is
the primary system requirement. Additionally, it is essential to confirm that each node is still present
and functioning. If a node was to be disabled or fail, it would represent a security violation that
should be reported. For security monitoring applications, the network must be configured so that
nodes are responsible for confirming the status of each other. One approach is to have each node
be assigned to peer that will report if a node is not functioning. The optimal topology of a security
monitoring network will look quite different from that of a data collection network.
It is reasonable to assume that each sensor should be checked approximately once per hour.
Combined with the ability to evenly distribute the load of checking nodes, the energy cost of
performing this check would become minimal. A majority of the energy consumption in a security
network is spent on meeting the strict latency requirements associated with the signaling of the
alarm when a security violation occurs.
Once detected, a security violation must be communicated to the base station immediately. The
latency of the data communication across the network to the base station has a critical impact on
the application performance. Users demand that alarm situations be reported within seconds of
detection. This means that network nodes must be able to respond quickly to requests from their
neighbours in order to forward data.
Currently there is a new generation of autonomous 3G sensors equipped with video cameras that
enable the development of new security, surveillance and military applications, the wireless sensor
network platform for the Internet of Things.
These new video camera sensors, in conjunction with the 3G communication module, allow the
creation of sensor nodes that transmit both discrete data gathered by analog and digital sensors
and complex streams of real time information, such as photos and video, to servers in the Cloud.

Figure 32 – 3G sensors stream photo and video to the Cloud for new security applications

ITU‐T's Technical Reports and Specifications 253