OFDM Technique Analysis for Underwater Communication Systems

Orthogonal Frequency Division Multiplexing (OFDM) has been widely used in communication systems due to its robustness against multipath interference and efficient bandwidth utilization. However, its application in underwater acoustic communication requires careful analysis due to the unique characteristics of underwater channels. Underwater environments are characterized by significant multipath effects caused by signal reflections from the water surface, seabed, and underwater objects, as well as refraction due to variations in the speed of sound. These phenomena lead to challenges such as Inter-Symbol Interference (ISI) and high attenuation, which degrade signal quality and increase error rates. The system is designed to be applicable for Autonomous Underwater Vehicles (AUVs) operating at relatively low speeds. This research focuses on optimizing OFDM parameters, particularly the number of subcarriers and the cyclic prefix (CP) length, to address these constraints and ensure reliable data transmission. Experiments conducted in the Hydrodynamics Laboratory of the National Research and Innovation Agency validate the OFDM system design under controlled underwater conditions. The results aim to provide a framework for maximizing the efficiency and reliability of underwater communication systems in dynamic channel environments.