System and method for time reversal data communications on pipes using guided elastic waves

摘要

Embedded piezoelectric sensors in large civil structures for structural health monitoring applications require data communication capabilities to effectively transmit information regarding the structure's integrity between sensor nodes and to the central processing unit. Conventional communication modalities include electromagnetic waves or acoustical waves. While guided elastic waves can propagate over long distances on solid structures, their multi-modal and dispersive characteristics make it difficult to interpret the channel responses and to transfer useful information along pipes. Time reversal is an adaptive transmission method that can improve the spatiotemporal wave focusing. The present disclosure presents the basic principles of a time reversal based pulse position modulation (TR-PPM) method and demonstrates TR-PPM data communication by simulation. The present disclosure also experimentally demonstrates data communication with TR-PPM on pipes. Simulated and experimental results demonstrate that TR-PPM for data communications can be achieved successfully using guided elastic waves.

主权项

1. A data communications method comprising:
in a dispersive multi-modal elastic channel that includes a plurality of sensors, at least two of the sensors capable of both transmitting and receiving a signal, probing the dispersive multi-modal elastic channel by transmitting a pilot elastic signal through the dispersive multi-modal elastic channel from at least one sensor capable of both transmitting and receiving a signal and configured and disposed as a destination sensor to at least another sensor capable of both transmitting and receiving a signal and configured and disposed as a source sensor; receiving the pilot elastic signal at the at least another sensor capable of both transmitting and receiving a signal and configured and disposed as a source sensor, and time reversing the received pilot elastic signal; modulating the time reversed elastic signal by pulse position modulation using a training preamble symbol to generate a time reversed pulse position modulated elastic preamble signal normalized by an energy normalization coefficient; modulating the time reversed elastic signal by pulse position modulation using an information carrying symbol to form a time reversed pulse position modulated elastic information carrying signal normalized by the energy normalization coefficient; and transmitting from the at least another sensor capable of both transmitting and receiving a signal and configured and disposed as a source sensor a total waveform that includes the normalized time reversed pulse position modulated elastic preamble signal followed by the normalized time reversed pulse position modulated information carrying signal to the at least one sensor capable of both transmitting and receiving a signal and configured and disposed as a destination sensor.