Wideband Time-varying Underwater Acoustic Channel Emulator

Robust underwater acoustic (UWA) communication is still a big challenge due to physical properties of the sea-water. Underwater acoustic propagation characterized by high attenuation, time-varying multipath propagation, and low speed of sound. Recent advancement in the cooperative operation of Autonomous Underwater Vehicles (AUVs) and Underwater Sensor Network (UWSN) are limited by these factors. Necessities to develop more robust UWA communication is not negligible. Sea trial is an expensive operation. A prior simulation and optionally emulation are usually used to enhance mission success rate. UWA emulator is a replica of an underwater channel and may contain hardware-in-the-loop (HIL). This tool is a bridge between the gaps of the simulation and real hardware-software behavior. However, UWA channel emulator is still underdeveloped. This paper explains the framework and the development of UWA channel emulator for a wideband and time-varying channel. Implementation of the convolution process has successfully done by using reloadable coefficient Finite Impulse Response (FIR) filter. First path propagation delay has also successfully implemented using a circular buffer. Designed emulator is applicable for less than 10 nodes before processing time is getting too high.