Variability of available capacity due to the effects of depth and temperature in the underwater acoustic communication channel

It is well established that path loss in the underwater acoustic channel is dependent on the transmission distance and signal frequency utilized, thereby causing the capacity to be dependent on transmission distance. It has been demonstrated that this dependence of capacity can lead to significant effects on the design of topologies for underwater acoustic networks. However, recent research in the field of underwater acoustics shows that attenuation also depends upon the depth and temperature of the environment, thereby influencing the available capacity in the channel. In light of the advent of multiple mobile vehicles being used underwater and also the high local variability of ocean conditions it is extremely important to also accurately take into account the effects of depth and temperature on the communication channel. In this paper we analyze the dependence of channel capacity upon depth and temperature by taking into account enhanced propagation loss and ambient noise models developed for the underwater acoustic channel. Numerical analysis provides us with quantification of available capacity, bandwidth and also optimum transmission strength necessary while using a time-invariant model. Due to the stark differences in the parameters effecting the underwater channel as compared to radio the results presented in this paper can be useful for designing novel approaches to maximize the performance of underwater networks.