Non-line-of-sight scattering channel modeling of MIMO links for underwater wireless optical communication

Abstract

Underwater wireless optical communication (UWOC) holds promising applications for achieving higher data rates and bandwidth in underwater communication. However, significant challenges arise due to high absorption and scattering effects in the underwater environment, coupled with the obstruction of transmission paths by unknown obstacles. Consequently, the development of UWOC technology faces substantial hurdles. In this context, we consider a non-line-of-sight (NLOS) UWOC multiple-input multiple-output (MIMO) configuration to enhance the performance of communication systems. In this paper, we initially utilize Monte Carlo simulations (MCS) to model the NLOS UWOC MIMO channel and then analyze the corresponding path loss and channel impulse response (CIR). An equal gain combining (EGC) method is employed at the receiver to merge the received signals. Subsequently, we use a weighted gamma function polynomial (WGFP) to simulate the CIR of NLOS UWOC MIMO links with an arbitrary number of light sources and detectors. Finally, we use the acquired CIR to calculate the system’s bit error rate (BER) under various configuration conditions. The MCS results indicate that, compared to single-input single-output (SISO) systems, MIMO systems experience a path loss reduction of over 3 dB, and the amplitude of the CIR increases by more than double, the BER performance has also seen significant improvement. Additionally, this validates the effectiveness of the WGFP model under NLOS conditions.