Composite channel modeling for underwater optical wireless communication and analysis of multiple scattering characteristics

In this study, we propose an innovative composite channel model that considers multi-size bubbles, absorption, and fading caused by scattering for investigating the effect of multiple scattering on the optical properties of a channel. The model is based on Mie theory, geometrical optics and the absorption-scattering model in the Monte-Carlo framework, and the performance of the optical communication system of the composite channel was analyzed for different positions, sizes, and number densities of bubbles. A comparison with the corresponding optical properties of conventional particle scattering indicated that a larger number of bubbles corresponded to greater attenuation of the composite channel, which was manifested by a low power at the receiver, an increased channel impulse response, and the observance of a prominent peak in the volume scattering function or critical scattering angles. Additionally, the effects of the position of large bubbles on the scattering property of the channel were investigated. The proposed composite channel model can provide reference data for designing a more reliable and comprehensive underwater optical wireless communication link.