scholarly journals Design of an Electrically Small, Planar Quasi-Isotropic Antenna for Enhancement of Wireless Link Reliability under NLOS Channels

2020 ◽  
Vol 10 (18) ◽  
pp. 6204 ◽  
Author(s):  
Sonapreetha Mohan Radha ◽  
Mingyu Jung ◽  
Pangun Park ◽  
Ick-Jae Yoon
Keyword(s):  
Directional Antennas ◽  
Radiation Efficiency ◽  
Line Of Sight ◽  
Delivery Ratio ◽  
Wireless Link ◽  
Received Signal Strength Indicator ◽  
Link Reliability ◽  
Receiving Antenna ◽  
Small Loop ◽  
Non Line Of Sight

The performance of wireless networks can be greatly influenced by the radiation pattern and polarization of the antennas at the nodes, especially when they are under non-line-of-sight (NLOS) channel environments. In this study, we designed a planar quasi-isotropic antenna based on the combination of a meandered electric dipole and an electrically small loop at a frequency of 2.45 GHz. Its electrical size (ka) is 0.47 and shows a gain deviation of 3.01 dB with radiation efficiency of 82.6% per the simulation. The performance of a wireless link under the line-of-sight and NLOS channels in an indoor environment was measured using the proposed quasi-isotropic antenna as a receiving antenna after validating its radiation and impedance properties experimentally (the measured gain deviation: 5.2 dB, the measured radiation efficiency: 79.2%). This study demonstrates that better properties are achieved using the quasi-isotropic antenna. The quasi-isotropic antenna shows an improved packet delivery ratio (PDR) and received signal strength indicator (RSSI) compared to the results using omni-directional antennas as a transmitting and receiving pair in the NLOS channels. To the best of our knowledge, the experimental validation of the enhancement of wireless link reliability using a quasi-isotropic antenna has not been reported before, and was first carried out in this study.

scholarly journals Implementation and evaluation of a 2.4 GHz multi-hop WSN: LoS, NLoS, different floors, and outdoor-to-indoor communications

2021 ◽  
Vol 11 (6) ◽  
pp. 5170
Author(s):  
Vasin Chaoboworn ◽  
Yoschanin Sasiwat ◽  
Dujdow Buranapanichkit ◽  
Hiroshi Saito ◽  
Apidet Booranawong
Keyword(s):  
Ieee 802.15.4 ◽  
Base Station ◽  
Sensor Nodes ◽  
Line Of Sight ◽  
Delivery Ratio ◽  
Packet Delivery ◽  
Communication Reliability ◽  
Ieee 802.15.4 Standard ◽  
Test Scenarios ◽  
Non Line Of Sight

In this paper, the communication reliability of a 2.4 GHz multi-hop wireless sensor network (WSN) in various test scenarios is evaluated through experiments. First, we implement an autonomous communication procedure for a multi-hop WSN on Tmote sky sensor nodes; 2.4 GHz, an IEEE 802.15.4 standard. Here, all nodes including a transmitter node (Tx), forwarder nodes (Fw), and a base station node (BS) can automatically work for transmitting and receiving data. The experiments have been tested in different scenarios including: i) in a room, ii) line-of-sight (LoS) communications on the 2nd floor of a building, iii) LoS and non-line-of-sight (NLoS) communications on the 1st floor to the 2nd floor, iv) LoS and NLoS communications from outdoor to the 1st and the 2nd floors of the building. The experimental results demonstrate that the communication reliability indicated by the packet delivery ratio (PDR) can vary from 99.89% in the case of i) to 14.40% in the case of iv), respectively. Here, the experiments reveal that multi-hop wireless commutations for outdoor to indoor with different floors and NLoS largely affect the PDR results, where the PDR more decreases from the best case (i.e., the case of a)) by 85.49%. Our research methodology and findings can be useful for users and researchers to carefully consider and deploy an efficient 2.4 GHz multi-hop WSN in their works, since different WSN applications require different communication reliability level.

scholarly journals Large-Scale Channel Modeling and Measurements for 10 GHz in Indoor Environments

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Iury S. Batalha ◽  
Andréia V. R. Lopes ◽  
Jasmine P. L. Araújo ◽  
Fabrício J. B. Barros ◽  
Bruno L. S. Castro ◽  
...  
Keyword(s):  
Large Scale ◽  
Channel Modeling ◽  
Directional Antennas ◽  
Measured Data ◽  
Comprehensive Analysis ◽  
Line Of Sight ◽  
Indoor Environments ◽  
Computer Engineering ◽  
Cross Polarization ◽  
Non Line Of Sight

With the advent of 5G mobile communication and researches into the propagation of large-scale channel modeling for frequencies above 6 GHz, measurement investigation was performed at 10 GHz with horn-type directional antennas in a corridor and a computer room within the Electrical and Computer Engineering Laboratories’ first floor, at Federal University of Pará (UFPA), Brazil. This paper presents data obtained through experimental work, channel modeling with co-polarization V-V and H-H and cross-polarization V-H in line-of-sight (LOS) or non-line-of-sight (NLOS) conditions. The large-scale close-in reference is sustained by a comprehensive analysis, considering propagation mechanisms such as reflection and diffraction. Results demonstrate that the established model had inferior standard deviation in relation to measured data, proving itself more significant to propagation in indoor environments.

The Improved Personnel Location Algorithm Based on RSSI

2013 ◽  
Vol 712-715 ◽  
pp. 2003-2006
Author(s):  
Sheng Mei Zhou ◽  
Ting Lei Huang
Keyword(s):  
Signal Strength ◽  
Wireless Sensor ◽  
Line Of Sight ◽  
Localization Algorithm ◽  
Matlab Simulation ◽  
Node Localization ◽  
Received Signal Strength Indicator ◽  
Positioning Accuracy ◽  
Location Algorithm ◽  
Non Line Of Sight

In the process of that based on the RSSI received signal strength indicator technique, resulting in the positioning accuracy is so low, since the simple RSSI, multipath, diffraction and non line of sight and other factors. In order to achieve higher accuracy node localization in wireless sensor, the paper is proposed based on the probability of recycling triangle centroid location algorithm in the RSSI technique,The probability of the cycle to handle triangle centroid localization algorithm. Through the Matlab simulation, compared with the traditional triangle centroid localization algorithm, the error is significantly reduced and positioning accuracy improved when the anchor point number exceeds a certain number.

scholarly journals Estimation of the number of people in an indoor environment based onWiFi received signal strength indicator

2021 ◽  
Vol 10 (3) ◽  
pp. 1475-1483
Author(s):  
Hakam Marwan Zaidan ◽  
Emad Ahmed Mohammed ◽  
Dheyaa Hussein Alhelal
Keyword(s):  
Indoor Environment ◽  
Polynomial Regression ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Line Of Sight ◽  
Concrete Wall ◽  
Received Signal Strength Indicator ◽  
The People ◽  
Two Stages ◽  
Non Line Of Sight

WiFi access points are widely spread everywhere in all our daily life routines. Using these devices to provide services other than the Internet is becoming familiar nowadays.This paper conducts an experimental study to estimate the number of people in an indoor environment through two system setups, line of sight, and non-line of sight. Relationship modeling between WiFi received signal and the number of people uses polynomial regression. The experiment comprised of two stages: first is the data collection from a controlled number of people. Then, the collected data used to train the system through polynomial regression. The second is testing the system’s effectiveness by applying it to an uncontrolled environment. Testing results revealed efficiency in using WiFi received signal strength to do the people counting (up to 60) because of the accuracy achievements of 93.17% in the line of sight system. The non-line of sight system disclosed randomness in the received signal strength indicator regardless of the change in the number of people. The  randomness is mainly caused by the fading effect of the concrete wall. Therefore it is inefficient to use the non-line of sight system in concrete buildings.

Integrating the Non-Line of Sight Launching System (NLOS-LS) in the United States Navy

2007 ◽  
Author(s):  
Jonathon Emis ◽  
Bryan Huang ◽  
Timothy Jones ◽  
Mei Li ◽  
Don Tumbocon
Keyword(s):  
United States ◽  
United States Navy ◽  
The United States ◽  
Line Of Sight ◽  
Non Line Of Sight

scholarly journals Low-cost SPAD sensing for non-line-of-sight tracking, material classification and depth imaging

2021 ◽  
Vol 40 (4) ◽  
pp. 1-12
Author(s):  
Clara Callenberg ◽  
Zheng Shi ◽  
Felix Heide ◽  
Matthias B. Hullin
Keyword(s):  
Low Cost ◽  
Line Of Sight ◽  
Depth Imaging ◽  
Material Classification ◽  
Non Line Of Sight

scholarly journals Target Localization via Integrated and Segregated Ranging Based on RSS and TOA Measurements

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 230 ◽  
Author(s):  
Slavisa Tomic ◽  
Marko Beko
Keyword(s):  
State Of The Art ◽  
Hybrid Approach ◽  
Critical Distance ◽  
Heuristic Approach ◽  
Target Localization ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Individual Measurement ◽  
New Approach ◽  
Non Line Of Sight

This work addresses the problem of target localization in adverse non-line-of-sight (NLOS) environments by using received signal strength (RSS) and time of arrival (TOA) measurements. It is inspired by a recently published work in which authors discuss about a critical distance below and above which employing combined RSS-TOA measurements is inferior to employing RSS-only and TOA-only measurements, respectively. Here, we revise state-of-the-art estimators for the considered target localization problem and study their performance against their counterparts that employ each individual measurement exclusively. It is shown that the hybrid approach is not the best one by default. Thus, we propose a simple heuristic approach to choose the best measurement for each link, and we show that it can enhance the performance of an estimator. The new approach implicitly relies on the concept of the critical distance, but does not assume certain link parameters as given. Our simulations corroborate with findings available in the literature for line-of-sight (LOS) to a certain extent, but they indicate that more work is required for NLOS environments. Moreover, they show that the heuristic approach works well, matching or even improving the performance of the best fixed choice in all considered scenarios.

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