Time for a preamble (underwater acoustic communication)

1. How does underwater acoustic communication work?
2. Which communication system is preferred for underwater communication?
3. What is very high frequency range for under water acoustic positioning systems?
4. Which of the following is a mode of communication underwater *?

How does underwater acoustic communication work?

An underwater transmitter directs a sonar signal to the water's surface, causing tiny vibrations that correspond to the 1s and 0s transmitted. Above the surface, a highly sensitive receiver reads these minute disturbances and decodes the sonar signal.

Which communication system is preferred for underwater communication?

OFDM is a favorable communication scheme in underwater acoustic communications thanks to its resilience against frequency selective channels with long delay spreads.

What is very high frequency range for under water acoustic positioning systems?

Typical frequencies associated with underwater acoustics are between 10 Hz and 1 MHz. The propagation of sound in the ocean at frequencies lower than 10 Hz is usually not possible without penetrating deep into the seabed, whereas frequencies above 1 MHz are rarely used because they are absorbed very quickly.

Which of the following is a mode of communication underwater *?

Acoustic waves are most commonly used underwater communication method employed nowadays because of the lower attenuation in sea water.