scholarly journals Model for Ray-Based UTD Simulations of the Human Body Shadowing Effect in 5G Wireless Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Łukasz Januszkiewicz
Keyword(s):  
Human Body ◽  
Communication Systems ◽  
Path Loss ◽  
Wireless Systems ◽  
Wireless Communication Systems ◽  
Human Body Model ◽  
Uniform Theory Of Diffraction ◽  
Indoor Wireless ◽  
Shadowing Effect ◽  
Difference Time

Shadowing effects caused by the obstructing presence of a human body can result in increased path loss in indoor wireless systems. This paper proposes a simplified model of a human body for use in ray-tracing simulations of indoor wireless communication systems based on the uniform theory of diffraction (UTD). The human body shadowing effect was first investigated using measurements and computer simulations employing the finite-difference time-domain method (FDTD). Based on the results, a human body model was elaborated for use in ray-based Remcom XGtd software. The model was developed for the 3.6 GHz band, which has been allocated for 5G wireless systems in many countries.

scholarly journals Analysis of Human Body Shadowing Effect on Wireless Sensor Networks Operating in the 2.4 GHz Band

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3412 ◽  
Author(s):  
Łukasz Januszkiewicz
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Human Body ◽  
Path Loss ◽  
Small Region ◽  
The Body ◽  
Wireless Sensor ◽  
Indoor Environments ◽  
Human Body Model ◽  
Shadowing Effect

Miniaturized wireless sensors are designed to run on limited power resources, requiring minimization of transmit power and lowering of the fade margin in the link budget. One factor that has an important impact on wireless sensor network design is path loss between the transmitter and the receiver. This paper presents an analysis of the influence of human bodies on path loss in the 2.4 GHz band, which is commonly used for wireless sensor networks. The effect of body shadowing was first analyzed in full wave computer simulations using the finite-difference time-domain method. Due to the high numerical burden, the simulations were limited to only a small region around the human body. To analyze the performance of networks in larger indoor environments, a human body model is proposed that can be used for simulations with a ray-based computer program. The proposed model of human body is the main contribution of this paper. It was used to analyze the body shadowing effect in a typical indoor environment. The results were found to be in good agreement with measurements.

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 Propagation Channel Measurements in the mm- and Sub-mm Wave Range for Different Indoor Communication Scenarios

2021 ◽  
Vol 42 (4) ◽  
pp. 357-370
Author(s):  
M. A. Salhi ◽  
T. Kleine-Ostmann ◽  
T. Schrader
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Wireless Communication Systems ◽  
Electromagnetic Spectrum ◽  
Channel Measurements ◽  
Frequency Range ◽  
Propagation Channel ◽  
Data Rates ◽  
Indoor Wireless ◽  
Wave Range

AbstractIncreasing data rates in wireless communications are accompanied with the need for new unoccupied and unregulated bandwidth in the electromagnetic spectrum. Higher carrier frequencies in the lower THz frequency range might offer the solution for future indoor wireless communication systems with data rates of 100 Gbit/s and beyond that cannot be located elsewhere. In this review, we discuss propagation channel measurements in an extremely broad frequency range from 50 to 325 GHz in selected indoor communication scenarios including kiosk downloading, office room communication, living rooms, and typical industrial environments.

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.

Reconfigurable Antenna

2016 ◽  
pp. 237-263
Author(s):  
Mohamad Kamal A Rahim ◽  
Huda A. A. Majid ◽  
Mohamad Rijal Hamid
Keyword(s):  
Communication Systems ◽  
Low Cost ◽  
Wireless Systems ◽  
Reconfigurable Antennas ◽  
Effective Length ◽  
Slot Antenna ◽  
Wireless Communication Systems ◽  
Reconfigurable Antenna ◽  
5 Ghz ◽  
Narrow Bands

Reconfigurable antennas have attracted a lot of attention especially in future wireless communication systems. Superior features such as reconfigurable capability, low cost, multi-purpose functions and size miniaturization have given reconfigurable antennas advantage to be integrated into a wireless systems. In this chapter, two types of reconfigurable antennas are discussed. First, frequency reconfigurable narrowband microstrip slot antenna (FRSA) is presented. The proposed antenna is designed to operate at six reconfigurable frequency bands from 2 GHz to 5 GHz with bidirectional radiation pattern. The second antenna design is frequency reconfigurable narrowband patch-slot antenna (FRPSA) is presented. The antenna is a combination of a microstrip patch and slot antenna. Nine different narrow bands are produced by tuning the effective length of the slot. The performances of the antenna in term of simulated and measured results are presented. In conclusion, good agreement between the simulated and measured results has been attained.

scholarly journals Compact Rectifier Circuit Design for Harvesting GSM/900 Ambient Energy

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1614
Author(s):  
Surajo Muhammad ◽  
Jun Jiat Tiang ◽  
Sew Kin Wong ◽  
Amjad Iqbal ◽  
Mohammad Alibakhshikenari ◽  
...  
Keyword(s):  
Circuit Design ◽  
Communication Systems ◽  
Path Loss ◽  
Input Power ◽  
Wireless Communication Systems ◽  
Rf Power ◽  
Total Size ◽  
High Input Power ◽  
Wide Range ◽  
Rf Energy

In this paper, a compact rectifier, capable of harvesting ambient radio frequency (RF) power is proposed. The total size of the rectifier is 45.4 mm × 7.8 mm × 1.6 mm, designed on FR-4 substrate using a single-stage voltage multiplier at 900 MHz. GSM/900 is among the favorable RF Energy Harvesting (RFEH) energy sources that span over a wide range with minimal path loss and high input power. The proposed RFEH rectifier achieves measured and simulated RF-to-dc (RF to direct current) power conversion efficiency (PCE) of 43.6% and 44.3% for 0 dBm input power, respectively. Additionally, the rectifier attained 3.1 V DC output voltage across 2 kΩ load terminal for 14 dBm and is capable of sensing low input power at −20 dBm. The work presents a compact rectifier to harvest RF energy at 900 MHz, making it a good candidate for low powered wireless communication systems as compares to the other state of the art rectifier.

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