Experimental Evaluation of Zp-Ofdm Scheme in Time Varying Underwater Multipath Channel

An experimental analysis to evaluate the practical suitability of the Underwater Acoustic (UWA) communication scheme is the major aim of this study. Oceanic channel imposes two major challenges (i.e., multipath propagation and Doppler effects) for underwater acoustic communication. Being fastest possible underwater information exchanger, OFDM is considered as the most viable option for mitigation of multipath. However, wideband nature of oceanic channel introduces severe Doppler shifts when dealing with OFDM subcarriers. Slight dynamics in a channel may cause overlapping of subcarriers such that entire signal can get completely distorted and sued as ICI (inter-carrier interference) induced transmission. In this study, we are presenting the algorithm to rectify the effects of Doppler shifts and to make OFDM technique more robust and more feasible for underwater environments. This study assures the performance of Zero-Padded Orthogonal Frequency Division Multiplexing (ZP-OFDM) based communication system in dynamic channel conditions. Data transmission using various packets structures are used to demonstrate the effectiveness of ZP-OFDM scheme. The narrow rectangular water tank of acoustic lab, Harbin Engineering University is utilized as a dynamic aquatic channel. The experimental results endorse the successful performance and suggest ZP-OFDM as a viable choice for high-rate communications over dynamic and high multipath oceanic channels.