Bidirectional Communications for Damage Monitoring Using Sensor Networks in Emergency Conditions

Wireless sensor networks have been studied for several applications. Disaster damage monitoring is one of the significant applications in sensor networks. If sensors are set up in buildings or on water pipelines, they could detect damage, victims trapped beneath rubble, or water leakage in case of a natural disaster. Since such a monitoring system is required to operate for a long term (e.g. several years) by batteries, power consumption of a node would be a critical issue. To fulfill the requirement, intermittent operation is employed in several medium access control (MAC) protocols in sensor networks. Moreover, those monitoring systems have to deal with several types of information, such as temperature, acceleration, alarm signals and so on, in some cases including image data to comprehend surrounding conditions. Some of them are gathered periodically, and some are in event-driven operation. Due to the diversity of information resources in sensor networks, the monitoring system requires short latency in bidirectional communications to control the process of data transmission dynamically. Considering these conditions, this paper describes a damage monitoring scheme using bidirectional low latency operation on a MAC protocol, which implements a short latency on bidirectional transmission in an active/sleep operation mode. Some fundamental evaluations show that the protocol is capable of achieving the short latency.