Low-Frequency Ultrasonic Communication for Speech Broadcasting in Public Transportation

Kwang Myung Jeon, Nam Kyun Kim, Chan Woong Kwak, Jung Min Moon, Hong Kook Kim


Speech broadcasting via loudspeakers is widely used in public transportation to send broadcast notifications. However, listeners often fail to catch spoken context from speech broadcasts due to excessive environmental noise. We propose an ultrasonic communication method that can be applied to loudspeaker-based speech broadcasting to cope with this issue. In other words, text notifications are modulated and carried over low-frequency ultrasonic waves through loudspeakers to the microphones of each potential listener’s mobile device. Then, the received ultrasonic stream is demodulated back into the text and the listener hears the notification context by a text-to-speech engine embedded in each mobile device. Such a transmission system is realized with a 20 kHz carrier frequency because it is inaudible to most listeners but capable of being used in communication between a loudspeaker and microphone. In addition, the performance of the proposed ultrasonic communication method is evaluated by measuring the success rate of transmitted words under various signal-to-noise ratio conditions.


Cite as: Jeon, K.M., Kim, N.K., Kwak, C.W., Moon, J.M., Kim, H.K. (2017) Low-Frequency Ultrasonic Communication for Speech Broadcasting in Public Transportation. Proc. Interspeech 2017, 2046-2047.


@inproceedings{Jeon2017,
  author={Kwang Myung Jeon and Nam Kyun Kim and Chan Woong Kwak and Jung Min Moon and Hong Kook Kim},
  title={Low-Frequency Ultrasonic Communication for Speech Broadcasting in Public Transportation},
  year=2017,
  booktitle={Proc. Interspeech 2017},
  pages={2046--2047}
}