Temporal variation on the tapped amplitude of propagating waves along a lift shaft in a complex campus environment is presented and modeled statistically in this letter. By using the Akaike's Information Criterion (AIC)-based method, distributions of amplitude of signals from different propagation mechanisms are studied separately. If the channel is considered as a whole, the Weibull function is identified as the best model for describing the temporal variation. The Kolmogorov-Smirnov (KS) test is applied to verify the selection of the Weibull model. Through the analysis of the Weibull -parameter, the severe temporal variations caused by the opening and closing of the lift door and the movement of the lift car within the lift shaft can clearly be identified. Signals reflected from buildings and walls in the intermediate and far regions do not suffer from much temporal variations. The Weibull function is ideal for the statistical modeling of channel propagation along the lift shaft. Using the Weibull -parameter, the dynamic channel along the lift shaft and the static channel from the intermediate and far regions can easily be classified.

The characterization of a Line of Sight (LOS) and a Non-Line of Sight (NLOS) link is performed over the military Ultra High Frequency (UHF) band (225 to 450 MHz). This is done using experimental results collected inside the cargo hold of a merchant ship. By analyzing the guiding effect associated with the cargo hold and its sub-structures, the channel characteristics of the environment can be determined. This important propagation mechanism is analyzed using the 3-D ray tracing simulator. Path loss for both topologies is studied and linear path loss models are proposed. Small-scale channel characteristics, such as the number of multipath components, decay factor of the multipath components and Root-Mean-Square (RMS) delay spread are studied and compared for the LOS and NLOS scenarios. Due to the guiding effect and multiple reflections along the cargo hold, both the LOS and NLOS scenarios are found to exhibit similar channel characteristics. A linear decay function is proposed to model the average Power Delay Profiles (PDPs). It is concluded that the linear model provides a good representation for the shape of the impulse responses for a cluttered environment with reflective substructures. This study is useful for the implementation of wireless sensor networks for status monitoring in maritime applications.Index Terms-3-D ray tracing, cargo hold, metallic structure, waveguide effect, wireless sensor network.

No abstract

Path loss for the outdoor-to-indoor channel in an urban environment is examined for the application of urban telecommunications in the UHF band. The path loss exponent and link availability for different receiver locations from within an urban office building to the outdoor urban environment are compared. This is useful for urban communication applications.

No abstract