Cezary Ziółkowski

Estimation of the Reception Angle Distribution Based on the Power Delay Spectrum or Profile

The paper presents an estimation of the reception angle distribution based on temporal characteristics such as the power delay spectrum (PDS) or power delay profile (PDP). Here, we focus on such wireless environment, where the propagation phenomenon predominates in azimuth plane. As a basis to determine probability density function (PDF) of the angle of arrival (AOA), a geometrical channel model (GCM) in form of the multielliptical model for delayed scattering components and the von Mises’ PDF for local scattering components are used. Therefore, this estimator is called the distribution based on multielliptical model (DBMM). The parameters of GCM are defined on the basis of the PDS or PDP and the relative position of the transmitter and the receiver. In contrast to the previously known statistical models, DBMM ensures the estimation PDF of AOA by using the temporal characteristics of the channel for differing propagation conditions. Based on the results of measurements taken from the literature, DBMM verification, assessment of accuracy, and comparison with other models are shown. The results of comparison show that DBMM is the only model that provides the smallest least-squares error for different environments.

Using SDF method for simultaneous location of multiple radio transmitters

The paper is devoted to the subject of simultaneous location of many radio waves emitting sources. The possibility to use the SDF method based on the Doppler effect and spectral analysis of signals received have been presented in it. The evaluation of the location procedure accuracy and time of realisation has been done according to simulation tests carried out.

Modeling the distribution of the arrival angle based on transmitter antenna pattern

An angular distribution of received signals has a significant impact on their spectral and correlational properties. Most of angular dispersion models do not consider antenna patterns. The developed procedure for determining the propagation path parameters enables a wide range of assessment of the impact of the propagation environment on the received signal properties. In contrast to the other models, this procedure is based on a geometrical structure, which parameters are defined on the basis of power delay profile or spectrum This modeling method allows also the power radiation pattern (PRP) of the transmitting antenna. The aim of the paper is to present the influence of the transmitter antenna PRP on the scattering propagation paths that arrive at the receiver. This analysis is realized on the basis of simulations studies using the developed procedure. Presented in this paper procedure maps the effects of propagation phenomena that predominate in an azimuth plane.

Influence of receiver/transmitter motion direction on the correlational and spectral characteristics — Simulation analysis

Numerous measurements show that both the spatial and environmental parameters have a significant effect on the deformation of the autocorrelation function (ACF) and the power spectrum density (PSD) of the received signals. However, the methods of analysis of these characteristics do not include this fact, as previously presented in the literature. For the first time in this paper, ACF and PSD are presented as a function of the receiver (Rx) / transmitter (Tx) motion direction. ACF and PSD are related to the velocity vector and the mutual position of objects (Tx, Rx). The analysis is based on simulation study results obtained by using the Doppler multi-elliptical channel model (DMCM). This study is conducted for a test scenario that allow the impact assessment of Rx/Tx motion direction on ACF and PSD. The test scenario is developed on the basis of the selected measurement, which is described in the literature. This makes it possible to verify the simulation results.

Localization of Emission Source in Urban Environment Based on the Doppler Effect

In urban environments, a multipath propagation and the Doppler effect are dominant phenomena that negatively affect the quality of service in wireless communications and realization of location methods. This paper presents the localization method of emission source in urban terrain for NLOS conditions based on the Doppler effect. To this aim, authors use the signal Doppler frequency (SDF) method. For mobile receiver locates and stationary transmitter, a spectrum of the received signal, called also the Doppler spectrum, is spread. On this basis, the estimation of the Doppler frequency shifts are used in SDF. In the paper, authors present a novel simple method of this estimation. Evaluation of SDF accuracy are obtained on the basis of simulation studies. The Doppler multi-elliptical channel model is used to the wireless channel modeling. In performed analysis, relative errors of transmitter location are in the order of single percent. Presented method can be easily used to PSK, OFDM and other emissions that have a harmonic in the signal spectrum.

Angular Dispersion Modelling for 5G Wireless Link with Directional Antennas

The development of fifth-generation (5G) systems is associated with the use of higher frequency bands and spatial multiplexing. A practical implementation of this multiplexing method is based on antenna arrays that allow the use of new technologies like active phased array antenna (APAA) or massive APAA. However, most of channel modeling methods available in a literature do not consider the selectivity of the transmitting and receiving antennas. In such cases, we can assume that the modeling is carried out for isotropic or omnidirectional antennas. In this paper, the angular dispersion modeling method for a 5G wireless link with directional antennas is shown what constitutes its novelty. The authors describe a multi-ellipsoid propagation model, which is the basis for simulation studies. Based on assumptions from real measurements for 38 GHz-39 GHz frequency range, an assessment of the influence of antenna directions and beamwidths on power angular spectrum and angle spreads in the azimuth and elevation planes is presented. The obtained simulation results show the importance of considering the three-dimensional modeling antenna patterns in the planning of 5G wireless lines.

SDF technology in location and navigation procedures: a survey of applications

The basis for development the Doppler location method, also called the signal Doppler frequency (SDF) method or technology is the analytical solution of the wave equation for a mobile source. This paper presents an overview of the simulations, numerical analysis and empirical studies of the possibilities and the range of SDF method applications. In the paper, the various applications from numerous publications are collected and described. They mainly focus on the use of SDF method in: emitter positioning, electronic warfare, crisis management, search and rescue, navigation. The developed method is characterized by an innovative, unique property among other location methods, because it allows the simultaneous location of the many radio emitters. Moreover, this is the first method based on the Doppler effect, which allows positioning of transmitters, using a single mobile platform. In the paper, the results of the using SDF method by the other teams are also presented.

Doppler Effect-Based Automatic Landing Procedure for UAV in Difficult Access Environments

Currently, almost unrestricted access to low-lying areas of airspace creates an opportunity to use unmanned aerial vehicles (UAVs), especially those capable of vertical take-off and landing (VTOL), in transport services. UAVs become increasingly popular for transporting postal items over small, medium, and large distances. It is forecasted that, in the near future, VTOL UAVs with a high take-off weight will also deliver goods to very distant and hard-to-reach locations. Therefore, UAV navigation plays a very important role in the process of carrying out transport services. At present, during the flight phase, drones make use of the integrated global navigation satellite system (GNSS) and the inertial navigation system (INS). However, the inaccuracy of GNSS + INS makes it unsuitable for landing and take-off, necessitating the guidance of a human UAV operator during those phases. Available navigation systems do not provide sufficiently high positioning accuracy for an UAV. For this reason, full automation of the landing approach is not possible. This paper puts forward a proposal to solve this problem. The authors show the structure of an autonomous system and a Doppler-based navigation procedure that allows for automatic landing approaches. An accuracy evaluation of the developed solution for VTOL is made on the basis of simulation studies.

Influence of the Doppler effect on signal fading parameters — simulation studies

The purpose of this paper is to assess the impact of transmission parameters of propagation environment on the properties of statistical fading. Assessment is shown on the basis of simulation studies that Doppler multi-elliptical channel model (DMCM) is used. Such parameters as level crossing rates (LCR) and average fade durations (AFD) are applied as a measure of intensity fading. In terms of statistical properties envelope, the obtained results show compliance of simulation results with a theoretical analysis. The paper presents the impact of the propagation environment type on the LCR and AFD. For this purpose, the authors use the power delay spectrum or profile on the basis of standard models, i.e., COST 207 and WINNER II.

Impact of Transmission Parameters of Propagation Environment on the Power Azimuth Spectrum

The paper is devoted to the problem of assessing the intensity of the angular power spectrum phenomenon of the received signals as a function of the propagation conditions in environment. To assess the impact of environment on the angular power spectrum, the multi-elliptical propagation model is used. Evaluation of angular power spectrum is shown as a function of the type propagation environment, direction signal transmission, and distance between transmitter/receiver. Here, the impact of the propagation environment type on the PAS shape and rms angle spread value is presented. For this purpose, the authors use the PDP or PDS on the basis of standard models, e.g., COST 207, WINNER, SMC.