Propagation delay in underwater networks — boon or bane?

The long propagation delay due to slow speed of sounds in water (as compared to speed of electromagnetic waves in air) has often been “blamed” for poor performance of network protocols in the underwater environment. While terrestrial network protocols are indeed severely impacted by propagation delay if directly used in underwater networks, we have shown that this is not the case for carefully designed propagation-delay-aware network protocols. In fact, the opposite is true — a well-designed underwater network protocol may be able to achieve a much higher network throughput in an environment with significant propagation delay, as compared to what the equivalent terrestrial networks might be able to achieve!

This counter-intuitive finding led to a series of protocols that utilized propagation delay in a constructive way. Read more about it in the blog article “What’s so super about super-TDMA?” by Dr. Anjangi, whose Ph.D. thesis focused on this idea of exploiting propagation delays in underwater networks.