Software Defined Ultrasonic System for Communication Through Solid Structures

RF signals are commonly used as a carrier signal in wireless communications. In some situations, like underwater, underground, closed containers or even intra-body, ultrasonic signal is a better carrier signal because RF signal attenuate very fast in these types of channels. Therefore, it is our objective is to assess the capability of using ultrasonic waves as a carrier waveform for communications. Ultrasonic signal is a type of waveform which has a frequency higher than 20 kHz. In this study, a ZYNQ System-on-Chip (SoC) platform is used to conduct ultrasonic communication experiments. This system consists of a transmitting transducer and a receiving transducer operating at MHz range frequencies. The transceiver unit operates using In-phase and Quadrature (IQ) modulation. With IQ modulation, different modulation schemes such as quadrature amplitude modulation (QAM), phase shift keying (PSK) can be readily implemented on the platform without modifying the hardware setup. Experiments are conducted in solid channels with various shape, material and size to explore the ultrasonic communication feasibility in diverse environments. Performance of different modulation methods are discussed and compared in this paper.