scholarly journals Optimization of Wireless Communication Coverage in Underground Tunnels Based on Zone Division

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yu Huo ◽  
Qingsong Hu ◽  
Yanjing Sun ◽  
Xiwang Guo ◽  
Liang Qi ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Fresnel Zone ◽  
Path Loss ◽  
Wireless Systems ◽  
Real Data ◽  
Communication Signal ◽  
Transmitting Antenna ◽  
Antenna Polarization ◽  
Zone Division ◽  
Multimodal Method

In order to reduce the path loss of the wireless communication signal in the underground tunnel, a scheme for configuring the antenna polarization of wireless systems based on a zone-division method is proposed. A multimodal method is used to estimate the effect of antenna polarization on the wireless propagation. When the optimal polarization of the antenna leading to low path loss is different in the zones near and far from the transmitting antenna, a dividing point is used to separate the zones. Experiments are conducted in an underground mine. It shows that the results by the multimodal method are consistent with the real data. Compared with the existing coverage schemes, the proposed scheme can obtain better coverage. Meanwhile, zone division has an important influence on the optimized performance of the wireless coverage. The zones divided based on Fresnel zone clearance and system identification are too small or too large, which result in incorrect polarization switching and high path loss.

Path Loss Model of the Maritime Wireless Communication in the Seas of Indonesia

2020 ◽  
Author(s):  
Arumjeni Mitayani ◽  
Galih Nugraha Nurkahfi ◽  
Mochamad Mardi Marta Dinata ◽  
Vita Awalia Mardiana ◽  
Nasrullah Armi ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Path Loss ◽  
Loss Model ◽  
Path Loss Model

scholarly journals Design of Wireless Communication System to Cover Specific Area by Using HAPS

2015 ◽  
Vol 1 (3) ◽  
pp. 357
Author(s):  
Kanar R. Tariq ◽  
Mohammed B. Majed ◽  
Zaid A. Hamid
Keyword(s):  
Wireless Communication ◽  
Communication System ◽  
New Technology ◽  
Elevation Angle ◽  
Path Loss ◽  
Specific Area ◽  
Coverage Area ◽  
Satellite Systems ◽  
The City ◽  
Mitigation Technique

This paper is meeting the principles of how to design coverage area for Sulaymaniyah city, using a new technology, which named HAPS. It started with small introduction for HAPS with its advantages, compare it with terrestrial and satellite systems, and specify requirements for design. Such as, specify the center of coverage area to find the coordinates. Then, supposed the coverage area for the city, elevation angle, and the location of earth stations which will connect HAPS with other networks and reduce the Interference with Fixed Services (FS) and Fixed Satellite Services (FSS).Mitigation technique of interference is given. Also, path loss and fading loss has been applied to meet the geographic of Sulaymaniyah city.

scholarly journals MEMS-BASED OSCILLATORS: A REVIEW

2014 ◽  
Vol 15 (1) ◽  
Author(s):  
Jamilah Karim ◽  
A. H. M. Zahirul Alam ◽  
Anis Nurashikin Nordin
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Systems ◽  
Wireless Communication Systems ◽  
Reference Frequency ◽  
Wireless System ◽  
Circuit Topology ◽  
Fully Integrated ◽  
Mems Technology ◽  
Accuracy And Stability

ABSTRACT: This paper presents an overview of microelectromechanical (MEMS) based oscillators. The accuracy and stability of the reference frequency will normally limit the performance of most wireless communication systems. MEMS technology is the technology of choice due to its compatibility to silicon, leading to integration with circuits and lowering power consumption. MEMS based oscillators also provide the potential of a fully integrated transceiver. The most commonly used topology for MEMS based oscillators are pierce oscillator circuit topology and TIA circuit topology. Both topologies result in very competitive output in terms of phase noise and power consumption.  They can be used for either higher or lower Rx. The major difference between both topologies is the number of transistors used. TIA circuit used more number of transistor compare to pierce circuit. Thus design complexity of the TIA is higher. Pierce circuit is simpler, provide straightforward biasing and easier to design. The highly integratable of MEMS-based oscillators have made them much needed in future multiband wireless system. So that future wireless systems are able to function globally without any problem. ABSTRAK: Kertas kerja ini membentangkan gambaran keseluruhan mikroelektromekanikal (MEMS) berdasarkan pengayun.  Ketepatan dan kestabilan frekuensi rujukan sering membataskan perlaksanaan kebanyakan sistem komunikasi tanpa wayar. Teknologi MEMS merupakan teknologi pilihan memandangkan ia serasi dengan silikon; membolehkan integrasi dengan litar dan penggunaan tenaga yang rendah.  Pengayun berdasarkan MEMS juga  berpotensi sebagai integrasi penuh penghantar-terima. Topologi yang sering digunakan untuk pengayun berdasarkan MEMS adalah topologi litar pengayun pencantas dan topologi litar TIA.  Keputusan bagi kedua-dua topologi adalah amat kompetitif dari segi fasa bunyi dan penggunaan tenaga. Ia boleh digunakan untuk meninggikan atau merendahkan Rx. Perbezaan utama di antara kedua-dua topologi adalah bilangan transistor yang digunakan. Litar TIA menggunakan bilangan transistor yang lebih daripada litar pencantas.  Maka, rekaan TIA adalah lebih rumit.  Litar pencantas adalah lebih ringkas, memberikan pincangan yang jelas dan rekabentuk yang mudah. Pengayun berdasarkan MEMS amat bersepadu menjadikan ia sesuai sebagai sistem tanpa wayar berbilang jalur masa depan.  Jesteru sistem tanpa wayar dapat berfungsi pada peringkat global tanpa sebarang kesulitan.

Appraisal of OFDM for multi-carrier, high-speed data rate wireless communication networks

2019 ◽  
Author(s):  
Muhammad Bello Abdullahi
Keyword(s):  
Wireless Communication ◽  
Communication Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Research Work ◽  
Wireless Systems ◽  
Data Rate ◽  
High Quality Research ◽  
Global Issues ◽  
High Speed Data

Orthogonal Frequency Division Multiplexing (OFDM) is used to achieve multi-carrier signals and high- Speed data rate in free space. OFDM-based systems operate in the hostile multipath radio environment, which allows efficient sharing of limited resources. This research work was designed, developed and simulated an OFDM System using the basic blocks of Simulink in MATLAB/Simulink software, to support multi-carrier, high-speed data rates. This was achieved in backing of collection and review of high-quality research papers, which reported the latest research developments in OFDM communications networks, and its applications in future wireless systems. The research work significantly increases the speed of data rate signals, and many critical problems associated with the applications of OFDM technologies in future wireless systems are still looking for efficient solutions. This would overcome the global issues and challenges facing the limited bandwidth in wireless communication network.

High-efficiency antenna-to-antenna polarization converters for customized polarization angle deflection

2020 ◽  
Vol 12 (7) ◽  
pp. 688-694
Author(s):  
Manlan Deng
Keyword(s):  
High Efficiency ◽  
Design Method ◽  
Ring Resonators ◽  
Polarization Angle ◽  
Dipole Antennas ◽  
Transmitted Waves ◽  
Angle Rotation ◽  
Transmitting Antenna ◽  
Antenna Polarization ◽  
Polarization Converters

AbstractIn this paper, an antenna-to-antenna method to design high-efficiency polarization converters was proposed. Two in-linked split ring resonators (SRRs) were used as the fundamental unit cell, which can effectively make the original linear polarization angle deflected into a customized one (include but not limited to 90°). The same as the process of energy reception and transmitting of microstrip symmetric dipole antennas, the top SRR plays the role of a receiving antenna and the bottom one acts as a transmitting antenna. Under normal illumination, the strong coupling between electric resonance and magnetic resonance can result in high transmission and broad bandwidth. Since the two SRRs act as two independently polarization selective components, the polarization angle of transmitted waves can be easily controlled by rotating the transmitting SRRs around the center. The proposed concept and the design method are validated using numerical simulations, as well as experimental results of three examples for 45, 60 and 90° polarization angle rotation, the polarization conversion ratio of which is about 92.2, 88.9 and 91.9% from 7.5 to 10 GHz.

Wave tracing: Ray tracing for the propagation of band-limited signals: Part 1 — Theory

Geophysics ◽  
2008 ◽  
Vol 73 (5) ◽  
pp. VE377-VE384 ◽  
Author(s):  
Kenneth P. Bube ◽  
John K. Washbourne
Keyword(s):  
Ray Tracing ◽  
High Frequency ◽  
Characteristic Frequency ◽  
Fresnel Zone ◽  
Imaging Techniques ◽  
Real Data ◽  
New Approach ◽  
Head Waves ◽  
Band Limited ◽  
Ray Bending

Many seismic imaging techniques require computing traveltimes and travel paths. Methods to compute raypaths are usually based on high-frequency approximations. In situations such as head waves, these raypaths minimize traveltime but are not paths along which most of the energy travels. We have developed a new approach to computing raypaths, using a modification of ray bending that we call wave tracing; it computes raypaths and traveltimes that are more consistent with the paths and times for the band-limited signals in real data than the paths and times obtained using high-frequency approximations. Wave tracing shortens the raypath while keeping the raypath within the Fresnel zone for a characteristic frequency of the signal.

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