Encoding Data by Frequency Modulation of a High-Low Siren Emitted by an Emergency Vehicle

It is important for people in surrounding vehicles to detect and respond appropriately to emergency vehicle sirens. This is a problem for everyone, but for the hearing impaired it can be particularly difficult. In addition, it would be useful if the siren could convey other information, such as the location of a shelter in the event of a disaster. The present study proposes data embedding into a high-low siren by frequency modulation. This information, including the location of the emergency vehicle, for example, can be extracted and utilized by a smartphone or car navigation system. The proposed method is more robust to Doppler shifts of siren frequencies, additive long-path echoes, and background noise than a previously proposed method. The current implementation can embed payload at a bit-rate of 12.3 bps. However, this rate can be more than doubled by using harmonics of the siren tone, which would provide a higher payload bit-rate than the previous method.