scholarly journals EMR: A new metric to assess the resilience of directional mmWave channels to blockages

2021 ◽  
Vol 2 (2) ◽  
pp. 47-60
Author(s):  
Fatih Erden ◽  
Ozgur Ozdemir ◽  
Ismail Guvenc ◽  
David W. Matolak
Keyword(s):  
Communication Systems ◽  
Communication Channel ◽  
Path Loss ◽  
Spatial Diversity ◽  
Line Of Sight ◽  
Communication Link ◽  
Weighted Sum ◽  
Channel Measurements ◽  
Angular Domain ◽  
Cosine Distance

Millimeter-wave (mmWave) communication systems require narrow beams to compensate for high path loss and to increase the communication range. If an obstacle blocks the dominant communication direction, alternative paths (directions) should be quickly identified to maintain reliable connectivity. In this paper, we introduce a new metric to quantify the Effective Multipath Richness (EMR) of a directional communication channel in the angular domain. In particular, the proposed metric takes into account the strength and spatial diversity of the resolved Multipath Components (MPCs), while also considering the beamwidth of the communication link and the blockage characteristics. The metric is defined as a weighted sum of the number of distinct MPC clusters in the angular domain, where the clustering of the MPCs is performed based on the cosine-distance between the dominant MPCs. For a given transmitter (TX) and receiver (RX) pair, the EMR is a single scalar value that characterizes the robustness of the communication link against blockages, as it captures the number of unique communication directions that can be utilized. It is also possible to characterize the blockage robustness for the whole environment by evaluating the spatial distribution of the EMR metric considering various different TX/RX locations. Using our proposed metric, one can assess the scattering richness of different environments to achieve a particular service quality. We evaluate the proposed metric using our 28 GHz channel measurements in a library environment for Line-of-Sight (LOS) and NLOS scenarios, and compare it with some other commonly used propagation metrics. We argue that EMR is especially informative at higher frequencies, e.g., mmWave and terahertz (THz), where the propagation attenuation is high, and directional Non-Light-of-Sight (NLOS) communication is critical for the success of the network.

scholarly journals Office Room Channel Modeling and Object Attenuation at Sub-THz Frequencies

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1725
Author(s):  
Brecht De Beelde ◽  
Emmeric Tanghe ◽  
Claude Desset ◽  
André Bourdoux ◽  
David Plets ◽  
...  
Keyword(s):  
Wireless Communication ◽  
High Throughput ◽  
Communication Systems ◽  
Path Loss ◽  
Channel Modeling ◽  
Single Frequency ◽  
Line Of Sight ◽  
Channel Measurements ◽  
V Band ◽  
Computer Mouse

Large bandwidths are needed to meet the high-throughput requirements of future wireless communication systems. These larger bandwidths are available at mmWave and sub-THz frequencies, such as the V-band ranging from 50 to 75 GHz and the D-band ranging from 110 to 170 GHz. In this paper, we present channel measurements in an office environment, covering the full D-band. Line-of-Sight (LOS) path loss (PL) is modeled as a function of frequency and distance. Both a single-frequency floating-intercept and multi-frequency alpha-beta-gamma model provide a good fit to the measured LOS PL data. Attenuation due to blockage of the LOS path by various desk objects, such as computer peripherals and cables, is determined, as well as attenuation due to plant obstructions. Attenuation due to an obstructed LOS path ranges from 3 dB for a single universal serial bus (USB) cable, and up to 25 dB for a laptop power supply, computer mouse, computer monitor, or plant. Because of a higher diffraction angle, the measured attenuation is higher when the distance between the antennas decreases. We measure diffraction around a computer monitor for dual polarization and verify whether communication via the reflected non Line-of-Sight path makes high-throughput wireless communication possible when the LOS path is blocked.

scholarly journals NLOS Path Loss Model for Low-Height Antenna Links in High-Rise Urban Street Grid Environments

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Juyul Lee ◽  
Myung-Don Kim ◽  
Hyun Kyu Chung ◽  
Jinup Kim
Keyword(s):  
Path Loss ◽  
Field Measurements ◽  
Propagation Path ◽  
Delay Spread ◽  
Communication Link ◽  
Channel Measurements ◽  
Loss Model ◽  
Path Loss Model ◽  
Power Delay Profile ◽  
High Rise

This paper presents a NLOS (non-line-of-sight) path loss model for low-height antenna links in rectangular street grids to account for typical D2D (device-to-device) communication link situations in high-rise urban outdoor environments. From wideband propagation channel measurements collected in Seoul City at 3.7 GHz, we observed distinctive power delay profile behaviors between 1-Turn and 2-Turn NLOS links: the 2-Turn NLOS has a wider delay spread. This can be explained by employing the idea that the 2-Turn NLOS has multiple propagation paths along the various street roads from TX to RX, whereas the 1-Turn NLOS has a single dominant propagation path from TX to RX. Considering this, we develop a path loss model encompassing 1-Turn and 2-Turn NLOS links with separate scattering and diffraction parameters for the first and the second corners, based on the Uniform Geometrical Theory of Diffraction. In addition, we consider the effect of building heights on path loss by incorporating an adjustable “waveguide effect” parameter; that is, higher building alleys provide better propagation environments. When compared with field measurements, the predictions are in agreement.

scholarly journals Analysis of transmission characteristics of non-line-of-sight ultraviolet light under complex channel conditions

2021 ◽  
Vol 336 ◽  
pp. 01012
Author(s):  
Xuan Zheng ◽  
Yanfeng Tang ◽  
Jingyi Du
Keyword(s):  
Ultraviolet Light ◽  
Path Loss ◽  
Mie Scattering ◽  
Spherical Particles ◽  
Dust Particles ◽  
Line Of Sight ◽  
Communication Link ◽  
Communication Quality ◽  
Long Distance ◽  
Non Line Of Sight

Using the multiple scattering model of non-line-of-sight ultraviolet light to simulate and analyze the atmospheric channel characteristics in the complex environment of haze and dust. The Mie scattering theory and T matrix method are used to analyze the path loss of spherical particles and non-spherical particles with particle concentration at different communication distances. The results show that when the communication distance is less than 50 meters, the communication quality under severe haze is the best, and for long-distance communication, the path loss under severe haze increases almost proportionally. In the non-line-of-sight ultraviolet light communication link, the higher the concentration of dust particles, the better the communication quality of the non-line-of-sight ultraviolet light communication transmission. Analysis of the scattering coefficient of spherical particles is significantly greater than that of non-spherical particles.

scholarly journals Enhancing the Performance of Medical Implant Communication Systems through Cooperative Diversity

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Barnabás Hegyi ◽  
János Levendovszky
Keyword(s):  
Cooperative Communication ◽  
System Performance ◽  
Communication Systems ◽  
Communication Channel ◽  
Cooperative Diversity ◽  
Communication Link ◽  
Medical Implants ◽  
Medical Implant ◽  
Cardioverter Defibrillators ◽  
Implant Communication

Battery-operated medical implants—such as pacemakers or cardioverter-defibrillators—have already been widely used in practical telemedicine and telecare applications. However, no solution has yet been found to mitigate the effect of the fading that the in-body to off-body communication channel is subject to. In this paper, we reveal and assess the potential of cooperative diversity to combat fading—hence to improve system performance—in medical implant communication systems. In the particular cooperative communication scenario we consider, multiple cooperating receiver units are installed across the room accommodating the patient with a medical implant inside his/her body. Our investigations have shown that the application of cooperative diversity is a promising approach to enhance the performance of medical implant communication systems in various aspects such as implant lifetime and communication link reliability.

scholarly journals Path-Loss Channel Models for Receiver Spatial Diversity Systems at 2.4 GHz

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Abdulmalik Alwarafy ◽  
Ahmed Iyanda Sulyman ◽  
Abdulhameed Alsanie ◽  
Saleh A. Alshebeili ◽  
Hatim M. Behairy
Keyword(s):  
Communication Systems ◽  
Path Loss ◽  
Spatial Diversity ◽  
Propagation Path ◽  
Real Field ◽  
Channel Models ◽  
Power Combining ◽  
Receiving Antenna ◽  
Diversity Systems ◽  
Loss Models

This article proposes receiver spatial diversity propagation path-loss channel models based on real-field measurement campaigns that were conducted in a line-of-site (LOS) and non-LOS (NLOS) indoor laboratory environment at 2.4 GHz. We apply equal gain power combining (EGC), coherent and noncoherent techniques, on the received signal powers. Our empirical data is used to propose spatial diversity propagation path-loss channel models using the log-distance and the floating intercept path-loss models. The proposed models indicate logarithmic-like reduction in the path-loss values as the number of diversity antennas increases. In the proposed spatial diversity empirical path-loss models, the number of diversity antenna elements is directly accounted for, and it is shown that they can accurately estimate the path-loss for any generalized number of receiving antenna elements for a given measurement setup. In particular, the floating intercept-based diversity path-loss model is vital to the 3GPP and WINNER II standards since they are widely utilized in multi-antenna-based communication systems.

scholarly journals Ray-Based Statistical Propagation Modeling for Indoor Corridor Scenarios at 15 GHz

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Qi Wang ◽  
Bo Ai ◽  
Ke Guan ◽  
David W. Matolak ◽  
Ruisi He ◽  
...  
Keyword(s):  
Communication Systems ◽  
Channel Model ◽  
Deterministic Model ◽  
Path Loss ◽  
Propagation Characteristic ◽  
Directional Antennas ◽  
Small Scale ◽  
Delay Spread ◽  
Channel Measurements ◽  
The Impact

According to the demands for fifth-generation (5G) communication systems, high frequency bands (above 6 GHz) need to be adopted to provide additional spectrum. This paper investigates the characteristics of indoor corridor channels at 15 GHz. Channel measurements with a vector network analyzer in two corridors were conducted. Based on a ray-optical approach, a deterministic channel model covering both antenna and propagation characteristic is presented. The channel model is evaluated by comparing simulated results of received power and root mean square delay spread with the corresponding measurements. By removing the impact of directional antennas from the transmitter and receiver, a path loss model as well as small-scale fading properties for typical corridors is presented based on the generated samples from the deterministic model. Results show that the standard deviation of path loss variation is related to the Tx height, and placing the Tx closer to the ceiling leads to a smaller fluctuation of path loss.

scholarly journals NEW UPPER AND LOWER BOUNDS LINE OF SIGHT PATH LOSS MODELS FOR MOBILE PROPAGATION IN BUILDINGS

2017 ◽  
Vol 24 (4) ◽  
pp. 407-418
Author(s):  
Supachai Phaiboon ◽  
P. Phokharatkul ◽  
Suripon Somkuarnpanit
Keyword(s):  
Lower Bounds ◽  
Communication Systems ◽  
Sample Path ◽  
Path Loss ◽  
Upper And Lower Bounds ◽  
Line Of Sight ◽  
Wireless Communication Systems ◽  
Indoor Wireless ◽  
Loss Models ◽  
Very High

This paper proposes a method to predict line-of-sight (LOS) path loss in buildings. We performed measurements in two different type of buildings at a frequency of 1.8 GHz and propose new upper and lower bounds path loss models which depend on max and min values of sample path loss data. This makes our models limit path loss within the boundary lines. The models include time-variant effects such as people moving and cars in parking areas with their influence on wave propagation that is very high.  The results have shown that the proposed models will be useful for the system and cell design of indoor wireless communication systems. 

scholarly journals Spatial Diversity Deconstruct of C-band Scatter Components in Multistatic RaDaR Datasets using Machine Learning Techniques

2021 ◽  
Author(s):  
Shanmugha Sundaram G A ◽  
Harun Surej I ◽  
Karthic S ◽  
Gandhiraj R ◽  
Binoy B N ◽  
...  
Keyword(s):  
Machine Learning ◽  
Communication Systems ◽  
Large Scale ◽  
Spatial Diversity ◽  
Machine Learning Techniques ◽  
Line Of Sight ◽  
Propagation Channel ◽  
Data Set ◽  
Band Frequency ◽  
Analytical Approaches

In complex application wherein the signal propagating through free space is subject to multipath interference due to scatter by line-of-sight and non-line-of-sight objects in the propagation channel. The aims is to identify scatter centers in the propagation channel and characterize them based on their subjective characteristics, interpreted based on machine learning algorithm operations. Data-driven models are employed, replacing the traditional analytical approaches, in order to profile the scatter centers as either of absorbing or reflecting types based on the manner in which the signals are affected. A typical multistatic detection scenario is reconstructed under controlled laboratory conditions in order to create spatially independent data sets, while operating in the C-band frequency. The outcomes of this study are then applied to identify the scatter centers based on the distinct signatures they register in the experimental data set. As a converse argument, the process of antenna pattern estimation can now be performed free of an anechoic chamber setup, which is time and cost insensitive. A greater relevance shall be in the context of mid-band 5G-NR cellular communication systems that need to optimize the distributed antenna location attributes on time and cost constrained scales before attempting a large-scale deployment.

scholarly journals Narrowband Interference Suppression in Wireless OFDM Systems

2009 ◽  
Vol 5 (1) ◽  
Author(s):  
Zlatka Nikolova ◽  
Georgi Iliev ◽  
Miglen Ovtcharov ◽  
Vladimir Poulkov
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Communication Channel ◽  
Digital Data ◽  
Communication Link ◽  
Narrowband Interference ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Signal Distortions ◽  
Channel Distortion

Signal distortions in communication systems occur between the transmitter and the receiver; these distortions normally cause bit errors at the receiver. In addition interference by other signals may add to the deterioration in performance of the communication link. In order to achieve reliable communication, the effects of the communication channel distortion and interfering signals must be reduced using different techniques. The aim of this paper is to introduce the fundamentals of Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA), to review and examine the effects of interference in a digital data communication link and to explore methods for mitigating or compensating for these effects.

scholarly journals Channel Measurements and Modeling at 6 GHz in the Tunnel Environments for 5G Wireless Systems

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Shuang-de Li ◽  
Yuan-jian Liu ◽  
Le-ke Lin ◽  
Zhong Sheng ◽  
Xiang-chen Sun ◽  
...  
Keyword(s):  
Path Loss ◽  
Measured Data ◽  
Line Of Sight ◽  
Delay Spread ◽  
Channel Measurements ◽  
Angle Of Arrival ◽  
Rms Delay Spread ◽  
K Factor ◽  
Reference Distance ◽  
Loss Models

Propagation measurements of wireless channels performed in the tunnel environments at 6 GHz are presented in this paper. Propagation characteristics are simulated and analyzed based on the method of shooting and bouncing ray tracing/image (SBR/IM). A good agreement is achieved between the measured results and simulated results, so the correctness of SBR/IM method has been validated. The measured results and simulated results are analyzed in terms of path loss models, received power, root mean square (RMS) delay spread, Ricean K-factor, and angle of arrival (AOA). The omnidirectional path loss models are characterized based on close-in (CI) free-space reference distance model and the alpha-beta-gamma (ABG) model. Path loss exponents (PLEs) are 1.50–1.74 in line-of-sight (LOS) scenarios and 2.18–2.20 in non-line-of-sight (NLOS) scenarios. Results show that CI model with the reference distance of 1 m provides more accuracy and stability in tunnel scenarios. The RMS delay spread values vary between 2.77 ns and 18.76 ns. Specially, the Poisson distribution best fits the measured data of RMS delay spreads for LOS scenarios and the Gaussian distribution best fits the measured data of RMS delay spreads for NLOS scenarios. Moreover, the normal distribution provides good fits to the Ricean K-factor. The analysis of the abovementioned results from channel measurements and simulations may be utilized for the design of wireless communications of future 5G radio systems at 6 GHz.

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