Wireless monitoring systems consist of sensor nodes, a base station and a data storage and control center.

Sensor nodes are small computers connected in a wireless network. These sensor nodes are equipped with various sensors, which measure physical characteristics. The sensor nodes are decentralized data loggers, which also act as relay stations forwarding data from neighboring nodes to the base station. Each sensor node independently selects a neighboring node suitable for a fast and reliable data transmission.

This ad-hoc communication network can be easily extended with additional sensor nodes, which autonomously join and integrate with the existing network. An additional advantage is the system reliability: if one of the sensor nodes fails and, thus, is no longer available as relay station, the affected sensor nodes independently establish new connections to operational nodes nearby.

The base station of the wireless communication network collects the data gathered by the sensor nodes and establishes a connection to the data storage and control center. This connection allows for a bidirectional communication of data and instructions between the control center and the wireless monitoring system. The base station is connected to the Internet over a mobile phone network (UMTS/GMS). This communication channel is encrypted which prevents reading or changing the data by a third party.

The data storage and control center receives, stores and analyses the measured data. Automatic analysis methods permit to detect unusual and undesired trends at an early stage and thus to take appropriate measures (e.g. alarming the responsible people). Sensor node configuration and remote maintenance of the network is performed from the control center.

The modular architecture of the system allows for easy adoption to a wide range of application requirements and makes it suitable for a variety of measurement tasks.