Design and Implementation of an Indoor Ultrasonic Communication System

In this paper, an indoor communication system using ultrasonic signals is described. The system uses differential binary phase-shift keying (DBPSK) for transmitting binary data as a part of an indoor positioning system. A synchronization and decoding approach is proposed that exploits the correlation properties of the DBPSK waveforms. All of the detection and decoding/demodulation processes are performed digitally - no analogue circuits are involved. Experiments that were carried out using off-the-shelf components confirmed the feasibility of the proposed system.