Cross-Evaluation of Waveform Modulation Schemes Using Post-Experimental Field Data for Underwater Acoustic Communications

In this paper, we extend the data dithering reuse (DDR) method to waveform modulation for underwater acoustic (UWA) communications, enabling post-experimental cross-evaluation between single carrier modulation (SCM) and orthogonal frequency division multiplexing (OFDM). The proposed DDR method respectively adds dithering and reverse dithering to the transmitted and received data of the original experimental scheme (OES) thus evaluating the new scheme under test (SUT). We first shows the necessary modifications to the standard testbed of the OES to prepare for DDR at the waveform level of the waveform modulation. We then describe the methods for generating waveform dithering sequences that includes the necessary adjustment to the OES data block that bridges SCM signals of different block lengths with OFDM signals with cyclic prefix (CP) or zero-padding (ZP) guard intervals. Subsequently, we provide a generic framework for multiple-input multiple-output (MIMO) soft-decision frequency-domain turbo equalization (FDTE) compatible with SCM and OFDM. Finally, numerical results using experimental data confirm that the proposed approach can achieve reliable post-experimental cross-evaluation.