This work presents a novel three-dimensional (3-D) scattering model to predict the path loss of a microcellular radio channel in an urban environment. The analytical scattering model combined with a patched-wall model predicts the median path loss more accurately than the conventional analytical ray-tracing model in the cases studied. Comparing the path loss with the measured one at 1.8 GHz dem...

This paper presents effectiveness of a RF-controlled spatial fading emulator on MIMO performance evaluation in a street microcell environment in comparison with a radio propagation test. The fading emulator can produce a radio propagation environment with a uniform and non-uniform angular power spectra (APS) in the horizontal plane. In this paper, we measured MIMO characteristics of four handse...

—The propagation prediction research has mainly focused on studying the radio propagation models in urban or rural land areas. In this paper, we extend a method for 950 MHz propagation prediction over sea based ITU-R Recommendation P.1546-5. A gauge of the accuracy of the prediction Free Space model, correction Okumura-Hata model and the P.1546-5 model is presented. The P.1546-5 is evaluated u...

Ray tracing algorithms rely on two dimensional or three dimensional database. They use ray optical techniques referred to as the uniform theory of diffraction (UTD) using building database given as polygons. Building geometries can also be modelled as having non-planar geometries, and this would be important in modeling of shadowing loss due to curved structures in urban radio propagation. To d...

The likelihood of line-of-sight (LoS) is an essential component in any radio channel model. It is particularly useful for radio network planning and urban coverage prediction. Empirical LoS models are hard to derive due to a strong dependency on local topology and the need for large measurement datasets. Since buildings are the major obstructions in a dense urban environment, we propose a new t...

To enhance the spectral efficiency and to improve service quality for cellular radio systems, a new microcellular system has been proposed [1-5] that operate over a relatively short radio path (on the order of 200 m to 1000 m), using relatively low antennas (about the same height as lamp posts), and transmitting at relatively low power (typically on the order of 10 m W). This new concept of mic...

Atmospheric radio ducts can trap VHF/UHF radio waves and propagate them over long distances. 284.4625 MHz Japanese radio wave signal measurements show that the radio waves are propagated to Korea coastal regions when ground temperatures exceed 10◦C. This paper discusses the reasons for the existence of this critical temperature threshold. key words: radio duct, duct propagation, critical temper...

In this paper, we propose the novel concept of a spectrum database for improving the efficiency of spectrum utilization. In the current design of TV white space spectrum databases, a propagation model is utilized to determine the spectrum availability. However, this propagation model has poor accuracy for radio environment estimation because it requires a large interference margin for the PU co...

It is a truism that simulations of mobile wireless networks (e.g., MANETs) are not realistic. There has been little effort in developing realistic mobility models and while propagation is well understood, it is rarely applied. In urban areas, the mobility of vehicles and pedestrians is greatly influenced by the environment (e.g., the location of buildings) as well as by interaction with other n...