Sonic communication research in underwater environments has gained considerable attention. The special circumstances of underwater communication bring new challenges, mostly related to communication distance and data transmission rate. Leveraging the latest technological progress, the authors investigate the use of a multi-input, multi-output (MIMO) filter bank multi-carrier (FBMC) system in underwater acoustic (UWA) communication. They explain and examine the sub-band coding (SBC) method to combat channel-related issues.

The introduction addresses the latest scientific achievements in UWA communication, including spatio-temporal processing for UWA channels, the impact of MIMO technology in UWA channel performance, the effectiveness of space-time trellis and layered space-time codes, the robustness of channel capacity in UWA, and MIMO orthogonal frequency-division multiplexing (OFDM) systems with space-time block coding in UWA. After presenting the drawbacks of the MIMO-OFDM platform in UWA communication, the authors discuss FBMC modulation systems.

The next section dissects the anatomy of the MIMO-FBMC system equipped with SBC processing, the key topic of the paper. The authors comprehensively discuss SBC processing, which decomposes the transmitted symbols into an independent frequency spectrum and distinguishable parts in the receiver. The paper then abruptly jumps to the simulation results, where readers can find the reasoning around the appropriateness of the method, including the special properties of UWA communication and an analytical discussion of its effectiveness.

The authors provide a good description of the FMBC modulation scheme and SBC processing, but the simulation results and bit error performance comparison are not satisfactory for a scientific paper of this level.