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Saturday, August 8, 2020 | History

2 edition of Extra-high frequency line-of-sight propagation for future urban communications found in the catalog.

Extra-high frequency line-of-sight propagation for future urban communications

Shahid Ahmed Khan

Extra-high frequency line-of-sight propagation for future urban communications

by Shahid Ahmed Khan

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  • 19 Currently reading

Published by University of Portsmouth, Dept. of Electrical and Electronic Engineering in Portsmouth .
Written in English


Edition Notes

Thesis (Ph.D.) - University of Portsmouth, 2000.

Statementby Shahid Ahmed Khan.
ID Numbers
Open LibraryOL18503436M

For line-of-sight conditions, the PL exponents are close to free space propagation at 60 GHz, but slightly smaller () for the street canyon at 10 GHz. The DS shows a clear dependence on the scenario (median values between 16 and 38 ns) and a strong distance dependence for the open square and the wide street canyon. This paper presents key parameters including the line-of-sight (LOS) probability, large-scale path loss, and shadow fading models for the design of future fifth generation (5G) wireless communication systems in urban macro- cellular (UMa) scenarios, using the data obtained from propagation measurements at 38 GHz in Austin, US, and at 2, 10, 18, and 28 GHz in Aalborg, Denmark.

Periodicals related to LIne-of-sight propagation Back to Top. Antennas and Propagation, IEEE Transactions on. Experimental and theoretical advances in antennas including design and development, and in the propagation of electromagnetic waves including scattering, diffraction and interaction with continuous media; and applications pertinent to antennas and propagation, such as remote sensing. the communications industry turned its attention to other technolo-gies, leading to a period of slow growth in High-Frequency (HF) radio communications during the s and s. However, HF, also known as short wave, has undergone an exciting revival .

  In line of sight (LOS) radio communications, the main route is the direct path between the transmitter and the receiver considering the curvature of radiowave trajectory. In Chap. 2, we discussed the general phenomena such as free space loss (FSL), gas and vapor loss, Fresnel radius, K -factor, and other mechanisms such as diffraction. In complex propagation scenarios such as caves, complex terrain, and indoor and urban environments, signal attenuation and multipath impose stringent conditions on power and signal processing. This is especially true at frequency bands where conventional communication systems operate (i.e., UHF and microwave bands).


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Extra-high frequency line-of-sight propagation for future urban communications by Shahid Ahmed Khan Download PDF EPUB FB2

Extra-High Frequency Line-of-Sight Propagation for Future Urban Communications Article in IEEE Transactions on Antennas and Propagation 51(11) - December with 43 Reads.

Extra-high frequency line-of-sight propagation for future urban communications Abstract: Spectrum congestion at conventional microwave frequencies has forced communication system designers to explore and investigate higher and higher frequencies, well Cited by: Extra-high frequency line-of-sight propagation for future urban communications.

This paper presents measurements, analysis and modeling of propagation losses for a GHz line-of-sight terrestrial link. The link was established in an urban environment over a path length of km and operated over a period of more than a by: Extra-high frequency line-of-sight propagation for future urban communications.

Author: Khan, Shahid Ahmed. Awarding Body: University of Portsmouth Current Institution: University of Portsmouth Date of Award: Availability of Full Text.

Extra-high frequency line-of-sight propagation for future urban communications By S. Khan, Abdul Tawfik, C. Gibbins and Boris Gremont No static citation data No static citation data Cite.

Extra-high frequency line-of-sight propagation for future urban communications S. Khan, Dr Abdulkarim Tawfik, C. Gibbins & Boris Gremont, NovIn: IEEE Transactions on Antennas and Propagation.

51, 11, p. 13 p. Aug During a sunspot maximum, the highly ionized F2 layer acts like a mirror, refracting the higher HF frequencies (above 20 MHz) with almost no lossabove that due to free space with communications at distances in excess of 10,miles commonplace using 10watts or less with frequencies in the 20 – 30MHz range.

A knowledge of radio propagation characteristics in the microcell environment is recognized to be essential for future frequency allocation and system impl Radio propagation measurements and modelling for line-of-sight microcellular systems - IEEE Conference Publication.

Antenna with diameter = 2 m, frequency = 6 GHz, wavelength = m G = dB Frequency = 14 GHz, same diameter, wavelength = m G = dB * Higher the frequency, higher the gain for the same size antenna Land Propagation The received signal power: where Gr is the receiver antenna gain, L is the propagation loss in the channel, i.e.

ijamec_Line of Sight(LoS) Probability Prediction for Satellite and HAPs Communication in Trabzon, Content uploaded by Volkan aydın Author content. communication ranges for future communication systems operating in a mobile-to-mobile environment, such as a relay urban and suburban non-line-of-sight environments with low elevation antennas for a transmitter and a receiver.

This wave signal with the carrier frequency of MHz was fed to the TX antenna with 30 dBm power. An omni. Line-of-sight propagation at ultrahigh frequencies is affected both by signal-strength variation due to multipath transmission and by bending of the beam due to abnormal variation of refractive index with height in the lower atmosphere.

At frequencies below about megahertz, and on paths having adequate clearance, the fading on line-of-sight paths is due to multipath transmission. This book covers the basic principles for understanding radio wave propagation for common frequency bands used in radio-communications.

This includes achievements and developments in propagation models for wireless communication. This book is intended to bridge the gap between the theoretical. In line-of-sight (LOS) radiocommunications, the main route is the direct path between the transmitter and receiver considering the curvature of radiowave trajectory.

In Chap. 2, we discussed the general phenomena such as free-space loss (FSL), gas and vapor loss, Fresnel radius, K-factor, and other mechanisms such as diffraction, reflection. Outdoor Cellular Communications Using Steerable Beam Antennas in New York City,” IEEE International Conference on Communications (ICC), June 9T.S.

Rappaport,et. al.,”Wideband Millimeter Wave Propagation Measurements and Channel Models for Future Wireless Communication System Design”, IEEE Trans. Comm., Vol. 63, No. MF = Medium Frequency EHF = Extra High Frequency III - - EU (future use) IV - - Japan V - - America, Australia, Brazil Propagation in free space always like light (straight line, line of sight).

K = ratio of the effective to the true radius of the earth. Over a smooth earth, a transmitter antenna at height h, (feet) and a receiving antenna at height hr (feet) are in radio line-of-sight provided the spacing in miles is less than (2 ht) 1/2 + (2 hr) 1/2 (assuming K = ).

In response to the call for propagation path loss models, members of the study group carried out measurements in the frequency bands between GHz up to 73 GHz in urban low‐rise and urban high‐rise as well as suburban environments.

Other methods of dealing with NLOS/BLOS are troposphere scatter (troposcatter) ionospheric propagation, which use the earth’s atmosphere as a reflector to propagate RF over the horizon. Troposcatter can increase range up to miles; ionospheric propagation can cover more than 2, miles.

[34], mmWave communications mainly rely on the LOS transmission. There are also channel measurements for mmWave cellular in other bands, such as the 28 GHz band, the 38 GHz band, and the 73 GHz band [35], [36].

Rappaport et al. [19] conducted the 28 GHz urban propagation campaign in New York City, where the distance between the transmitter (TX.RF Communication Lecture # 1.

Dr. Irfan Ahmed Introduction to RF Propagation By: Seybold J.S. FREQUENCY DESIGNATIONS The electromagnetic spectrum is loosely divided into regions as shown in Table [1]. During World War II, letters were used to designate various frequency bands, particularly those used for radar. These designations were classified at the time, but have found their way.Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter (one decimeter).Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range.