Rafal Szumny

Attenuation of multipath components using directional antennas and circular polarization for indoor wireless positioning systems

This paper presents results of investigation concerning method for decreasing errors of TOA based indoor wireless positioning systems caused by multipath components. Presented method is based on directional antennas with small side lobes level. Additionally, for attenuation some of multipath components arriving from LOS direction circular polarization antennas are analyzed. The paper describes typical channel profiles for indoor environment and its influence to positioning error. Next, results of simulations are presented. Paper concludes with evaluation of antenna beamwidth and polarization into positioning accuracy based on simulation results.

A 5.8 GHz Local Positioning and Communication System

In this paper, we present a hybrid local positioning and communication system under development within the scope of the EU funded RESOLUTION project. Very stringent requirements to positioning accuracy combined with tight bandwidth limitations demand innovative approaches to combat channel multipath effects. Closely spaced multipath components are the dominant cause of error in the system. Results of system simulations utilizing indoor channel scenarios and measurements using a discrete prototype are presented to prove the possibility of achieving the design goals in spite of limiting spectral regulations.

Measurements and Analysis of the Propagation Channel for Various Indoor Environments

The paper presents measurements results of the propagation channel for three types of indoor environments. Basing on these results statistical analysis and comparison of obtained data are presented. Short review of channel profile measurement techniques are also presented. The paper includes discussion of indoor channel propagation type influence on positioning systems accuracy. Measurements were part of EU VI FP RESOLUTION project, in which WUT was responsible for propagation and antennas work package.

Neural Networks in Indoor Positioning System Based on Power Delay Profile

This paper presents analysis of wireless terminal location in buildings. Problems related to this topic and possible solutions are shortly presented. Paper includes results of indoor location system simulations based on neural network and power delay profile

Computer Simulations of the Propagation Channel for Various Indoor Environments

This paper presents the results of computer simulations performed as a part of EU VI FP RESOLUTION project. Conducted research concerns propagation of radio waves inside large halls. Channel characteristics influencing on accuracy of microwave positioning system were determined by means of ray-tracing method. Various propagation scenarios, locations of transmitter and radiation patterns of transmitting antenna were taken into consideration.

Closely Spaced Paths Effect Mitigation for Indoor Location Systems

Paper presents a proposal of method for closely spaced paths mitigation for indoor location system based on spread spectrum signals. At the beginning issue of closely spaced paths influence for the accuracy of TO A determination is explained. In the following part results of indoor propagation simulations are presented. These simulations show relationship between delays and directions of arrival of power delay profile components. The proposal of simple four-element null steering antenna array, which can mitigate this effect, is proposed. The paper contains also results of measurements showing influence of multipath propagation to coarse code synchronization.

Antenna diversity impact to indoor wireless TOA-based positioning systems accuracy

This paper presents analysis of antenna diversity impact to distance measurement error of indoor TOA-based positioning systems. First channel impulse response shaping methods and indoor TOA-based systems accuracy aspects are shortly discussed. In the following part of the paper obtained results for two types of data (ray-tracing simulations, measurements) and for various TOA detection techniques are presented. Paper concludes with summary of our research.

Project Resolution; Reconfigurable Systems for Mobile Local Communication and Positioning

The aim of RESOLUTION project is developing of a wireless three-dimensional (3D) local positioning system with resolution in the centimetre regime and real-time ability. The system is intended to work in environment with strong multipath effects and fading. The solution will be implemented in advanced CMOS technology. Main project goals are: development of a wireless 3D high accuracy local positioning system, a novel frequency modulated continuous wave (FMCW) radar principle with pulsed active reflector will be employed, positioning system will be implemented on basis of common WLAN systems, to allow multifunctional tasks, highly integrated system on chip (SoC) frontends will be designed on advanced CMOS technology, smart power and adaptive performance control will be applied to minimize the power consumption according to application needs, in order to enhance the performance and coverage range, the transceiver features adaptive antenna combining in the radio frequency (RF) receiver.