As an important scatterer in vehicle-to-X (V2X) communication scenarios, traffic signs frequently appear along roads and can affect the propagation channel appreciably. Although traffic signs can be considered as an important part in such scattering scenarios, knowledge of their bistatic radar cross section (RCS) is still absent. This paper presents an integration of the analytical models, full-wave simulation, measurement, and validation of the bistatic RCS of three types of representative traffic signs for V2X communication. First, the total RCS of the traffic signs is calculated by summing up the field contributions of the individual parts with their own phase relationships. Furthermore, simulations using full-wave analysis are performed to validate the analytical models for RCSs in the far field under plane-wave illumination. Since the high-frequency calculation techniques used here are applicable only under plane-wave excitation, the traffic-sign parts are divided into small elements, where this precondition is locally valid. Measurements are conducted in an open-area test site at the National Metrology Institute of Germany to validate the model in the near field (spherical wave from a point source). Corresponding comparisons show that the method of decomposing the traffic sign into small parts supports an effective way to embed the analytical models into ray-tracing tools, thus improving propagation modeling in V2X communication.

The accuracy of Global Navigation Satellite Systems (GNSSs) is degraded by a physical phenomenon known as multipath propagation. Among other kinds of interactions with the environment, diffraction by wedges is present in almost any situation. In this paper, this effect is modeled by using the well established Uniform Theory of Diffraction (UTD). This diffraction model has been integrated into a ray tracing tool based on the Geometrical Optics (GO) theory. The implementation is validated by using wedges made of metal at higher frequencies using scaled measurements. Thereafter, ray tracing simulations are carried out in order to assess the influence of this effect on satellite based navigation systems.

Multipath propagation has a strong impact on the accuracy of satellite-based positioning. In this work, multipath effects are investigated by means of a measurement campaign and ray tracing propagation modelling. A GNSS receiver placed in a scenario with a single ground reflector was used for this purpose. From the deterministic channel modelling, the impact of multipath propagation is analysed by means of the oscillations introduced in the carrier-to-noise density ratio.

In this paper, a software-defined radio (SDR) receiver used for the investigation of multipath propagation effects on Global Navigation Satellite Systems (GNSS) is presented. The receiver is based on the low-cost Universal Software Radio Pheripheral (USRP) and a set of free-available MATLAB programs. Moreover, the software has been enhanced by implementing a method to estimate the carrier-to-noise density ratio, a key parameter when investigating multipath. In order to test the approach, a GNSS measurement campaign was conducted and the results are presented here.

As an important scatterer in Vehicle-to-X (V2X) communication scenarios, traffic signs frequently appear along the roads and highly influence the radio channel. This paper presents a set of simulations and measurements for the bistatic radar cross section (RCS) of various realistic traffic signs. The simulations are performed by using full-wave analysis, whereas measurements are conducted at an open area test site at the national metrology institute of Germany. This investigation yields results for the bistatic RCS of traffic signs. It also focuses both on relevant simulation and measurement issues for interpreting their scattering behavior, the knowledge of which can improve the design of V2X communication systems.

Multipath propagation has a major contribution in the degradation of the achieved positioning accuracy. In high precision applications, where mm accuracy is crucial, multipath caused errors dominate the total error budget. In this investigation, in a first step, we use the results of a ray-tracing approach in order to characterize the influence of multiple-multipath propagation. The characteristics of the propagation channel, which are estimated by the ray-tracing tool, are used as input for the investigation of the impact of multipath propagation on GNSS observables. In a second step, a closer look on GNSS signal amplitudes will be presented. The model presented in this paper is adopted from wireless network simulations and the signal amplitude of each signal component involved is estimated for each epoch separately based on the geometry and the receiving antenna pattern. The model is validated with a simple geometry controlled experiment.

Multipath propagation between satellite and receiver constitutes an important impairment in satellite navigation systems. To address this problem, an extensive investigation on the propagation channel is required. In this paper, the satellite-to-earth channel is modelled deterministically by using the ray tracing method in combination with an accurate 3-dimensional description of the environment in which the receiver is located. Moreover, this work focuses on the influence of diffraction propagation phenomena based on the Uniform Theory of Diffraction (UTD). For a typical GNSS reference station environment we show different diffracted rays and power delay profiles. We find a good agreement between the measurements and simulation results.

Satellite positioning accuracy is degraded by multipath propagation between satellite and the receiver. In this paper we give an overview of a new approach to model and correct this impairment, and present some preliminary results. High accuracy 3D laser scanning is utilized to model the environment. This gives an accurate basis for the characterization of the satellite to earth radio channel by using ray tracing. The information extracted from the ray tracing simulations is used to design correction algorithms that will be implemented in GNSS software defined radio (SDR) receivers.

This paper investigates the performance of the 60 GHz IEEE 802.15.3c physical layer (PHY) specification in terms of bit error rate (BER) against signal to noise ratio. Two PHY modes of the standard have been implemented and simulated, i.e., Single Carrier and High Speed Interface. The first mode uses single carrier (SC) block transmission and the second mode uses orthogonal frequency division multiplexing (OFDM). One of the main issues in the new 60 GHz standards is multipath propagation, which plays an important role in the link quality. Thus, we have tested the PHY with the IEEE standard channel model, ray tracing simulations and real 60 GHz measurements.