Window effect on wall penetration loss in mobile communications
In mobile communication scenarios, a window opening on a wall enhances the field strength inside the room, as compared to a whole wall. Scarce models in the literature address this topic, or objectively quantify this effect relating it to window dimensions - this is the objective of the present paper. Wall and window are treated as an antenna aperture with the appropriate field distribution, which re-radiates its near field into the room. Measurements on a scaled model of a wall with different window sizes show good agreement with simulations. Based on simulation results, a statistical model is constructed to enable fast quantification of the window effect through a "window gain" parameter.
ULTRAWIDEBAND CHANNEL SOUNDING STUDIES IN OUTDOOR AND OUTDOOR-INDOOR ENVIRONMENTS
Ultrawideband (UWB) is one of the most promising communication technologies in recent times with the promise of high data rates and spectral reuse. This work analyses the outdoor and outdoor-to-indoor propagating characteristics of the UWB pulse, which can be of the order of a few gigahertz in bandwidth. The aim of the thesis is to provide the parameters needed in order to develop a channel model for such cases. The channel model would then play an important role in determining physical layer (PHY) solutions to optimally exploit these characteristics. The measurements carried out on the Virginia Tech campus are used to compute parameters such as path loss, penetration loss and delay statistics. These are carried out in multiple frequency bands and the results are compared across frequency bands to determine effect of different frequency levels on the parameters. Finally the results are analyzed with respect to similar parameters obtained in other measurement campaigns in an attempt to evaluate the performance of Ultrawideband vis-àvis narrowband systems.
Multipath propagation model for line-of-sight street microcells in urban area
This paper proposes a multipath propagation model for line-of-sight (LOS) street microcells with building roof base sites (BS) in urban areas, Multipath propagation characteristics are of great importance in evaluating the performance of digital systems and designing wireless links. Typical delay profiles are measured to clarify their statistical characteristics in LOS street microcells. The channel sounder used is a sliding correlator with 30-Mb/s PN code and a center frequency of 2.6 GHz. The measurements clarify the features of delay profile and mean RMS delay spread. The proposed delay profile model explains one plausible mechanism of multipath propagation. The delay profiles calculated using the model agreed well with the measured profiles. Furthermore, the factors influencing the RMSs delay spread are investigated, and the regression equation of medium RMS delay spread on a sidewalk is established. The proposed model can evaluate the transmission characteristics of wireless digital communication systems in multipath propagation environments.