Passing-by Ship Shadowing Model for Ship-to-Shore Maritime Communication

To address the multi-scenario requirements of maritime communication in 6G integrated space-air-ground-sea networks, this paper investigates the large-scale channel properties of the shadowing effect induced by passing-by ships in a ship-to-shore (S2S) maritime communication scenario. In this paper, a geometric model for the passing-by ship shadowing effect was proposed, fully accounting for the impact of earth curvature. The model derives sea surface elevation, quantifies the orthogonal deviation of the ship's position relative to the transmitter-receiver (TX-RX) axis, and utilizes a key-node algorithm for real-time dynamic estimation of ship position, velocity, and geometric attributes. Based on the measured data, a shadowing effect occurred beyond the distance of 0.6 times the first Fresnel zone (FFZ), a critical threshold determining whether earth curvature causes diffraction loss on the radio link, is further investigated. Applicability constraints of the model are defined based on the angle of diffraction. Simulation results demonstrate that the proposed model achieves significant improvements in shadowing loss prediction compared to the existing models. Additionally, the paper demonstrates how the temporal node framework enables maritime ship parameter perception, extracting ship height distributions and motion characteristics from shadowing patterns through an inverse modeling approach, which establishes a theoretical foundation for Integrated Sensing and Communication in maritime applications.