NPB777

I wish to transmit sensor data. Expected data rate is around few tens of Kbps.

Hello, I am very much interested to how frequency of sound varies in water. Also, how the frequency varies with temperature and depth? What are the different formulas related to this? Secondly, how can we determine the best frequency of operation? I would be very thankful if anyone could answer the above questions or point to materials explaining the above. With regards