An efficient subcarrier arrangement for airborne OFDM communication using parametric loudspeaker

Abstract

Acoustic communication in air has attracted attention as an alternative near-field communication medium. A parametric loudspeaker has the potential to achieve acoustic communication within a personal area. However, secondary nonlinear components of communication signals generated by self-demodulation in air become barriers to acoustic communication. Although the use of orthogonal frequency division multiplexing (OFDM) would be desirable, since it achieves low-calculation-cost equalization at the receiver even in a multipath fading environment, inter-carrier interference (ICI) with secondary components degrades communication quality. In this paper, we propose an efficient subcarrier arrangement for OFDM communication using parametric loudspeakers. We consider two subcarrier arrangements: odd-comb OFDM and narrow-band OFMD. The former has an active subcarrier at odd indexes, and the latter has a restricted frequency band to avoid ICI. We also test the proposed schemes in experiments. The experimental results suggest that the proposed OFDM successfully improves communication quality compared to the original OFDM.

Indoor self-localization using multipath arrival time measured by a single acoustic ranging sensor

“…[15][16][17][18][19] Various time-of-flight (ToF) measurement methods have been proposed by applying digital communication technology. [20][21][22][23][24][25][26][27] Numerical methods for moving sources have also been proposed for the design of sensors and measurement algorithms. 28) A method using ultrasonic sensors can detect transparent objects and is not much affected by optical scatterers.…”