Multipath propagation in line-of-sight links

1979 ◽  
Vol 15 (7) ◽  
pp. 209 ◽  
Author(s):  
L. Boithias
Keyword(s):  
Multipath Propagation ◽  
Line Of Sight

Multipath propagation model for line-of-sight street microcells in urban area

2000 ◽  
Vol 49 (2) ◽  
pp. 422-427 ◽  
Author(s):  
S. Ichitsubo ◽  
T. Furuno ◽  
T. Taga ◽  
R. Kawasaki
Keyword(s):  
Urban Area ◽  
Multipath Propagation ◽  
Propagation Model ◽  
Line Of Sight

scholarly journals A Ray-Tracing Technique to Characterize GPS Multipath in the Frequency Domain

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Naveen S. Gowdayyanadoddi ◽  
James T. Curran ◽  
Ali Broumandan ◽  
Gérard Lachapelle
Keyword(s):  
Frequency Domain ◽  
Ray Tracing ◽  
Multipath Propagation ◽  
Doppler Frequency ◽  
Real Data ◽  
Frequency Difference ◽  
Line Of Sight ◽  
Gps Measurements ◽  
Sources Of Error ◽  
Non Line Of Sight

Multipath propagation is one of the major sources of error in GPS measurements. In this research, a ray-tracing technique is proposed to study the frequency domain characteristics of multipath propagation. The Doppler frequency difference, also known as multipath phase rate and fading frequency, between direct (line-of-sight, LOS) and reflected (non-line-of-sight, NLOS) signals is studied as a function of satellite elevation and azimuth, as well as distance between the reflector and the static receiver. The accuracy of the method is verified with measured Doppler differences from real data collected in a downtown environment. The use of ray-tracing derived predicted Doppler differences in a receiver, as a means of alleviating the multipath induced errors in the measurement, is presented and discussed.

scholarly journals A Deep Learning Approach to Position Estimation from Channel Impulse Responses

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1064 ◽  
Author(s):  
Arne Niitsoo ◽  
Thorsten Edelhäußer ◽  
Ernst Eberlein ◽  
Niels Hadaschik ◽  
Christopher Mutschler
Keyword(s):  
Deep Learning ◽  
State Of The Art ◽  
Multipath Propagation ◽  
Position Estimation ◽  
Line Of Sight ◽  
Learning Approach ◽  
Impulse Responses ◽  
Mobile Objects ◽  
Accurate Position ◽  
Industrial Environments

Radio-based locating systems allow for a robust and continuous tracking in industrial environments and are a key enabler for the digitalization of processes in many areas such as production, manufacturing, and warehouse management. Time difference of arrival (TDoA) systems estimate the time-of-flight (ToF) of radio burst signals with a set of synchronized antennas from which they trilaterate accurate position estimates of mobile tags. However, in industrial environments where multipath propagation is predominant it is difficult to extract the correct ToF of the signal. This article shows how deep learning (DL) can be used to estimate the position of mobile objects directly from the raw channel impulse responses (CIR) extracted at the receivers. Our experiments show that our DL-based position estimation not only works well under harsh multipath propagation but also outperforms state-of-the-art approaches in line-of-sight situations.

scholarly journals Experimental Evaluation of Multipath Mitigation in TDOA-Based Indoor Passive Localization System Using A Beam Steering Broadband Circular Polarization Antenna

Electronics ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 362 ◽  
Author(s):  
Changjiang Su ◽  
Yanqun Liu ◽  
Leilei Liu ◽  
Mei Yang ◽  
Hongxin Zhao ◽  
...  
Keyword(s):  
Circular Polarization ◽  
Experimental Evaluation ◽  
Multipath Propagation ◽  
Beam Steering ◽  
Line Of Sight ◽  
Indoor Environments ◽  
Rf Switch ◽  
Multipath Mitigation ◽  
Localization System ◽  
Passive Localization

An experimental evaluation of multipath mitigation using a beam steering broadband circular polarization antenna (BSBCPA) in indoor passive localization system based on time differences of arrival (TDOA) is presented in this paper. The BSBCPA consists of a beam switch network, four identical hexagon patch elements and their respective feeding networks. By controlling the states of a radio frequency (RF) switch in the beam switch network, four steering circular polarization beams can be excited separately for azimuth omnidirectional coverage. Combining the spatial selectivity of steering beams and circular polarization in the BSBCPA, the positioning inaccuracy from indoor multipath propagation can be mitigated. In two different indoor environments with line of sight (LOS), complex multipath, when transmitting a 20 MHz bandwidth signal in WLAN, the 2D positioning mean error obtained is 0.7 m and 0.82 m, respectively. Compared with conventional omnidirectional linear polarization antenna (OLPA), the BSBCPA can at least improve positioning accuracy by 51%. The experimental results show that the proposed BSBCPA can significantly mitigate multipath propagation for TDOA-based indoor passive localization.

Case study of line-of-sight microwave multipath propagation

1987 ◽  
Vol 23 (10) ◽  
pp. 483-484 ◽  
Author(s):  
K.H. Craig ◽  
G.R. Kennedy
Keyword(s):  
Multipath Propagation ◽  
Line Of Sight

scholarly journals Performance of BER with Different Diversity Techniques for Millimeter-Wave Communication System

2019 ◽  
Vol 8 (6S4) ◽  
pp. 1149-1152 ◽  
Keyword(s):  
Antenna Arrays ◽  
Communication System ◽  
Mimo Systems ◽  
Multipath Propagation ◽  
Line Of Sight ◽  
60 Ghz ◽  
Diversity Techniques ◽  
Single Output ◽  
Single Input ◽  
Diversity Technique

In a communications system, a diversity technique is used to enhance the reliability of a message signal by using at least two channels with different characteristics. In this paper, all four possible scenarios are considered: Single-input and singleoutput (SISO), single input and multi-output (SIMO), multipleinput and single-output (MISO), Multiple-input and multiple output (MIMO) systems. Antenna arrays will be used to reduce BER and improve the performance of the system using array gain in the line of sight channel for 60 GHz frequency in an indoor scenario. Single input and single output are investigated before analysis of multiple inputs and multiple output channel in the line of sight (LOS) and multipath propagation. MATLAB simulation has been performed using BPSK modulation. The comparative studies show that the performance of the MIMO diversity technique is more reliable in terms of BER to improve the performance and efficiency of the communication system.

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