An underwater acoustic channel model using ray tracing in ns-2

Underwater Acoustic Sensor Network (UASN) is the enabling technology for real-time underwater monitoring and data collection. The costly underwater trials and unknown underwater acoustic modem infrastructures increase the need and importance of a reliable network simulator for UASNs. The underwater acoustic propagation method used in the channel modeling is the one of the determining factors influences the reliability level of the network simulator for UASNs. However, recent models implemented in popular open-source network simulators prefer to use empirical formulas due to the computational complexity of the propagation method for inclusion. This preference means neglecting the multipath, fading, and shadow zone effects. Disregarding these effects results in unreal communication links between sensor nodes and approximate propagation loss and delay computation. In this paper, we present the design and implementation of our underwater acoustic channel model developed to eliminate the multipath, fading, and shadow zone effects by using ray tracing propagation method in the ns-2 network simulator. We also compare our model with a previously proposed model. The results show that the considerable differences in spreading loss and propagation delay occur due to the approximation.