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

2002 ◽  
Author(s):  
S. Ichitsubo ◽  
T. Furuno ◽  
T. Nagato ◽  
T. Taga ◽  
R. Kawasaki
Keyword(s):  
Urban Areas ◽  
Multipath Propagation ◽  
Propagation Model ◽  
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 Novel Target-Height Estimation Approach Using Radar-Wave Multipath Propagation for Automotive Applications

2017 ◽  
Vol 15 ◽  
pp. 61-67
Author(s):  
Amir Laribi ◽  
Markus Hahn ◽  
Jürgen Dickmann ◽  
Christian Waldschmidt
Keyword(s):  
Continuous Wave ◽  
Multipath Propagation ◽  
Estimation Error ◽  
Propagation Model ◽  
Target Range ◽  
Target Height ◽  
Height Estimation ◽  
Range Resolution ◽  
Novel Target ◽  
Radar Wave

Abstract. This paper introduces a novel target height estimation approach using a Frequency Modulation Continuous Wave (FMCW) automotive radar. The presented algorithm takes advantage of radar wave multipath propagation to measure the height of objects in the vehicle surroundings. A multipath propagation model is presented first, then a target height is formulated using geometry, based on the presented propagation model. It is then shown from Sensor-Target geometry that height estimation of targets is highly dependent on the radar range resolution, target range and target height. The high resolution algorithm RELAX is discussed and applied to collected raw data to enhance the radar range resolution capability. This enables a more accurate height estimation especially for low targets. Finally, the results of a measurement campaign using corner reflectors at different heights are discussed to show that target heights can be very accurately resolved by the proposed algorithm and that for low targets an average mean height estimation error of 0.03 m has been achieved by the proposed height finding algorithm.

scholarly journals GNSS Multipath Detection Using Continuous Time-Series C/N0

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4059
Author(s):  
Nobuaki Kubo ◽  
Kaito Kobayashi ◽  
Rei Furukawa
Keyword(s):  
Time Series ◽  
Continuous Time ◽  
Urban Areas ◽  
Satellite System ◽  
Line Of Sight ◽  
Static Tests ◽  
Gnss Receivers ◽  
Multipath Detection ◽  
Global Navigation Satellite ◽  
Multipath Errors

The reduction of multipath errors is a significant challenge in the Global Navigation Satellite System (GNSS), especially when receiving non-line-of-sight (NLOS) signals. However, selecting line-of-sight (LOS) satellites correctly is still a difficult task in dense urban areas, even with the latest GNSS receivers. This study demonstrates a new method of utilization of C/N0 of the GNSS to detect NLOS signals. The elevation-dependent threshold of the C/N0 setting may be effective in mitigating multipath errors. However, the C/N0 fluctuation affected by NLOS signals is quite large. If the C/N0 is over the threshold, the satellite is used for positioning even if it is still affected by the NLOS signal, which causes the positioning error to jump easily. To overcome this issue, we focused on the value of continuous time-series C/N0 for a certain period. If the C/N0 of the satellite was less than the determined threshold, the satellite was not used for positioning for a certain period, even if the C/N0 recovered over the threshold. Three static tests were conducted at challenging locations near high-rise buildings in Tokyo. The results proved that our method could substantially mitigate multipath errors in differential GNSS by appropriately removing the NLOS signals. Therefore, the performance of real-time kinematic GNSS was significantly improved.

scholarly journals A Novel Radio Wave Propagation Modeling Method Using System Identification Technique over Wireless Links in East Africa

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Solomon T. Girma ◽  
Dominic B. O. Konditi ◽  
Ciira Maina
Keyword(s):  
Wave Propagation ◽  
System Identification ◽  
Radio Wave ◽  
Free Space ◽  
Urban Areas ◽  
Radio Channel ◽  
Signal Propagation ◽  
Propagation Model ◽  
Radio Wave Propagation ◽  
Study Region

Transmission of a radio signal through a wireless radio channel is affected by refraction, diffraction and reflection, free space loss, object penetration, and absorption that corrupt the originally transmitted signal before radio wave arrives at a receiver antenna. Even though there are many factors affecting wireless radio channels, there are still a number of radio wave propagation models such as Okumura, Hata, free space model, and COST-231 to predict the received signal level at the receiver antenna. However, researchers in the field of radio wave propagation argue that there is no universally accepted propagation model to guarantee a universal recommendation. Thus, this research is aimed at determining the difference between the measured received signal levels and the received signal level calculated from the free space propagation model. System identification method has been proposed to determine this unknown difference. Measured received signal levels were collected from three randomly selected urban areas in Ethiopia using a computer, Nemo test tool, Actix software, Nokia phone, and GPS. The result from the simulations was validated against the received experimental signal level measurement taken in a different environment. From the simulation results, the mean square error (MSE) was 4.169 dB, which is much smaller than the minimum acceptable MSE value of 6 dB for good signal propagation, and 74.76% fit to the estimation data. The results clearly showed that the proposed radio wave propagation model predicts the received signal levels at 900 MHz and 1800 MHz in the study region.

scholarly journals A Semi-Deterministic Channel Model for VANETs Simulations

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jonathan Ledy ◽  
Hervé Boeglen ◽  
Anne-Marie Poussard ◽  
Benoît Hilt ◽  
Rodolphe Vauzelle
Keyword(s):  
Hybrid Model ◽  
Urban Areas ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Channel Model ◽  
Propagation Model ◽  
Network Simulator ◽  
Physical Layers ◽  
Hoc Networks ◽  
Simulation Time

Today's advanced simulators facilitate thorough studies on Vehicular Ad hoc NETworks (VANETs). However the choice of the physical layer model in such simulators is a crucial issue that impacts the results. A solution to this challenge might be found with a hybrid model. In this paper, we propose a semi-deterministic channel propagation model for VANETs called UM-CRT. It is based on CRT (Communication Ray Tracer) and SCME—UM (Spatial Channel Model Extended—Urban Micro) which are, respectively, a deterministic channel simulator and a statistical channel model. It uses a process which adjusts the statistical model using relevant parameters obtained from the deterministic simulator. To evaluate realistic VANET transmissions, we have integrated our hybrid model in fully compliant 802.11 p and 802.11 n physical layers. This framework is then used with the NS-2 network simulator. Our simulation results show that UM-CRT is adapted for VANETs simulations in urban areas as it gives a good approximation of realistic channel propagation mechanisms while improving significantly simulation time.

scholarly journals Target Detection in Low Grazing Angle with Adaptive OFDM Radar

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Yang Xia ◽  
Zhiyong Song ◽  
Zaiqi Lu ◽  
Hao Wu ◽  
Qiang Fu
Keyword(s):  
Target Detection ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multipath Propagation ◽  
Random Phase ◽  
Grazing Angle ◽  
Detection Performance ◽  
Propagation Model ◽  
Ratio Test ◽  
Multipath Effect ◽  
Adaptive Ofdm

Multipath effect is the main factor of deteriorating target detection performance in low grazing angle scenario, which results from reflections on the ground/sea surface. Amplitudes of the received signals fluctuate acutely due to the random phase variations of reflected signals along different paths; thereby the performances of target detection and tracking are heavily influenced. This paper deals with target detection in low grazing angle scenario with orthogonal frequency division multiplexing (OFDM) radar. Realistic physical and statistical effects are incorporated into the multipath propagation model. By taking advantage of multipath propagation that provides spatial diversity of radar system and frequency diversity of OFDM waveform, we derive a detection method based on generalized likelihood ratio test (GLRT). Then, we propose an algorithm to optimally design the transmitted subcarrier weights to improve the detection performance. Simulation results show that the detection performance can be improved due to the multipath effect and adaptive OFDM waveform design.

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