Lossless Compression Techniques in Wireless Sensor Networks: Monitoring Microacoustic Emissions

Collapse of rock faces and stability assessment of buildings is related to the geological substrate or the nature of the concrete and the presence of fractures which influence the stability properties of the envisaged material. A wireless sensor network-based approach has been suggested to monitor crack formation which, due to the high sampling rate of sensors, requires both online temporal identification of the event and compression of the same before transmittal to a remote control room (the action containing the energy consumption of the unit by triggering and reducing the radio activity). The paper proposes a simple -yet effective-algorithm for detecting microacoustic emissions generated by formation/organization of cracks and identifies a suitable lossless technique for microacoustic event compression. Finally, to satisfy real time performance, the optimal processing chain has been implemented on a FPGA chip to be mounted onto the WSN units.