Reduced-complexity Underwater Acoustic Communication Using MIMO Orthogonal Signal Division Multiplexing with BPDN

Underwater acoustic (UWA) communication is a promising technology for constructing underwater data links. We focus on multiple-input-multiple-output (MIMO)-signaling to achieve reliable UWA communication. This paper applies a global optimum solution of basis pursuit denoising (BPDN) in orthogonal signal division multiplexing (OSDM) to reduce computational complexity of channel estimation precess. Although MIMO signaling achieves the same data rate as single-input- multiple-output (SIMO) signaling with a lower baud rate, MIMO requires more computational time in signal processing due to the existence of numerous channel impulse responses compared with SIMO case. We also conducted a sea trial with a mobile boat to evaluate the proposed method in terms of communication quality and computational complexity. As a result, the proposed channel estimator achieves the same communication quality reducing 83% computational time. We expect that our channel estimator will play an important role in realizing reliable UWA communication.