Comparison of Propagation along a Lift Shaft in Two Complex Environments

Signal variation caused by motions along the lift shaft in a campus environment and on board a ship is compared. The guiding effect is common for both lift shafts, and the variation in amplitude of the guided signals is more significant for the lift shaft with larger dimensions. Unlike the lift shaft within the campus, the ship with its lift shaft forms a ‘waveguide within waveguide’ structure. Therefore, the reflected signals within the ship enclosure outside the lift shaft are significantly affected by the motion along the lift shaft. Due to the difference in the degree of the signal variations in these two environments, the rms delay spread is found to be closely related to the lift door status and the lift car position in the campus environment, whereas it is not significantly affected by the motions along the lift shaft in the ship environment. From the statistical study and comparison of the signal variations in the two environments, the Weibull probability density function is found to be the most suitable model to describe analogous waveguide channels such as the lift shaft and the ship enclosure.