This document provides an outline and overview of topics related to mobile radio propagation, including:
- Definitions of key terms like wavelength, frequency, propagation mechanisms, and radio frequency bands.
- Descriptions of different propagation effects like reflection, diffraction, and scattering.
- Explanations of path loss in various environments and how it relates to distance and frequency.
- Discussions of slow fading/shadowing and fast fading/multipath effects on received signals.
- Concepts of Doppler shift, delay spread, and intersymbol interference in mobile radio systems.
Rayleigh Fading Channel In Mobile Digital Communication SystemOUM SAOKOSAL
The document discusses Rayleigh fading channels in mobile digital communication systems. It describes how multipath propagation can cause multipath fading or scintillation. It distinguishes between large-scale fading and small-scale fading. Large-scale fading refers to mean signal attenuation over large areas and variations around the mean due to shadowing. Small-scale fading is also called Rayleigh fading and refers to time spreading of signals and time variance of channels due to small changes in position.
This document discusses radio channel modeling and the effects of multipath fading. It describes narrowband and wideband channel modeling approaches. Narrowband channels cause signal fading due to destructive interference from multiple propagation paths. Wideband channels cause signal dispersion in addition to fading. Channel characteristics like delay spread, Doppler spread, and coherence bandwidth are defined. Common fading distributions like Rayleigh and Rice are also summarized. Techniques to mitigate fading effects in narrowband and wideband systems are outlined.
Introduction To Wireless Fading ChannelsNitin Jain
The document summarizes key concepts related to wireless fading channels, including:
1. Multipath fading causes fluctuations in signal strength over small physical distances due to constructive and destructive interference from multiple signal paths.
2. Rayleigh fading occurs when there is no line-of-sight path between transmitter and receiver, resulting in fast, large fluctuations in signal strength over small physical distances.
3. Doppler spread and coherence time describe how quickly the wireless channel varies over time due to mobility, with fast fading occurring if the channel changes significantly within a symbol period.
This document discusses wireless communication and radio wave propagation. It covers various types of fading that can occur for wireless signals, including small-scale and large-scale fading. Small-scale fading is caused by multipath propagation and can be frequency selective, flat, fast or slow depending on factors like bandwidth and receiver/transmitter motion. Doppler shift from movement introduces a change in frequency. Mitigation techniques for multipath fading include diversity methods using space, frequency or time as well as adaptive equalization and forward error correction.
The document discusses small-scale fading and multipath propagation in wireless communications. It describes how multipath propagation leads to fading effects as multiple versions of the transmitted signal combine at the receiver. Channel sounding techniques are used to measure the power delay profile and characterize the time dispersion parameters of mobile radio channels, including mean excess delay, RMS delay spread, and maximum excess delay. Direct pulse systems, spread spectrum correlators, and frequency domain analysis are channel sounding methods discussed.
This document discusses Friis transmission formula for free space path loss. It defines key terms like power density, effective aperture, and antenna gain. The Friis formula calculates received power as a function of transmitted power, transmitter and receiver gains, wavelength, and distance. It states that path loss increases with distance and is inversely proportional to the square of the distance. The document also notes some drawbacks of the Friis model and conditions for applying it in the far field region.
This document provides an overview of GSM link budget calculations. It defines key terms used in link budgets such as effective radiated power, antenna gain, diversity gain, receiver sensitivity, path loss, and fade margin. It explains the objectives of calculating a link budget are to estimate maximum allowable path loss, compute required effective isotropically radiated power for a balanced link, estimate coverage design thresholds, and evaluate technology performance. It also provides examples of uplink and downlink link budget calculations for a GSM network and defines indoor, in-car, and outdoor coverage requirements.
1) The document discusses parameters used to characterize mobile multipath channels including power delay profile, mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time.
2) These parameters are derived from the power delay profile and describe aspects of the channel such as time dispersion, frequency selectivity, and time variation due to Doppler shift.
3) Examples of typical values for different channel parameters are given for outdoor and indoor mobile radio channels.
Rayleigh Fading Channel In Mobile Digital Communication SystemOUM SAOKOSAL
The document discusses Rayleigh fading channels in mobile digital communication systems. It describes how multipath propagation can cause multipath fading or scintillation. It distinguishes between large-scale fading and small-scale fading. Large-scale fading refers to mean signal attenuation over large areas and variations around the mean due to shadowing. Small-scale fading is also called Rayleigh fading and refers to time spreading of signals and time variance of channels due to small changes in position.
This document discusses radio channel modeling and the effects of multipath fading. It describes narrowband and wideband channel modeling approaches. Narrowband channels cause signal fading due to destructive interference from multiple propagation paths. Wideband channels cause signal dispersion in addition to fading. Channel characteristics like delay spread, Doppler spread, and coherence bandwidth are defined. Common fading distributions like Rayleigh and Rice are also summarized. Techniques to mitigate fading effects in narrowband and wideband systems are outlined.
Introduction To Wireless Fading ChannelsNitin Jain
The document summarizes key concepts related to wireless fading channels, including:
1. Multipath fading causes fluctuations in signal strength over small physical distances due to constructive and destructive interference from multiple signal paths.
2. Rayleigh fading occurs when there is no line-of-sight path between transmitter and receiver, resulting in fast, large fluctuations in signal strength over small physical distances.
3. Doppler spread and coherence time describe how quickly the wireless channel varies over time due to mobility, with fast fading occurring if the channel changes significantly within a symbol period.
This document discusses wireless communication and radio wave propagation. It covers various types of fading that can occur for wireless signals, including small-scale and large-scale fading. Small-scale fading is caused by multipath propagation and can be frequency selective, flat, fast or slow depending on factors like bandwidth and receiver/transmitter motion. Doppler shift from movement introduces a change in frequency. Mitigation techniques for multipath fading include diversity methods using space, frequency or time as well as adaptive equalization and forward error correction.
The document discusses small-scale fading and multipath propagation in wireless communications. It describes how multipath propagation leads to fading effects as multiple versions of the transmitted signal combine at the receiver. Channel sounding techniques are used to measure the power delay profile and characterize the time dispersion parameters of mobile radio channels, including mean excess delay, RMS delay spread, and maximum excess delay. Direct pulse systems, spread spectrum correlators, and frequency domain analysis are channel sounding methods discussed.
This document discusses Friis transmission formula for free space path loss. It defines key terms like power density, effective aperture, and antenna gain. The Friis formula calculates received power as a function of transmitted power, transmitter and receiver gains, wavelength, and distance. It states that path loss increases with distance and is inversely proportional to the square of the distance. The document also notes some drawbacks of the Friis model and conditions for applying it in the far field region.
This document provides an overview of GSM link budget calculations. It defines key terms used in link budgets such as effective radiated power, antenna gain, diversity gain, receiver sensitivity, path loss, and fade margin. It explains the objectives of calculating a link budget are to estimate maximum allowable path loss, compute required effective isotropically radiated power for a balanced link, estimate coverage design thresholds, and evaluate technology performance. It also provides examples of uplink and downlink link budget calculations for a GSM network and defines indoor, in-car, and outdoor coverage requirements.
1) The document discusses parameters used to characterize mobile multipath channels including power delay profile, mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time.
2) These parameters are derived from the power delay profile and describe aspects of the channel such as time dispersion, frequency selectivity, and time variation due to Doppler shift.
3) Examples of typical values for different channel parameters are given for outdoor and indoor mobile radio channels.
The document provides an overview of MIMO (multiple-input multiple-output) systems in wireless communications. It discusses how MIMO can provide array gain, diversity gain, and multiplexing gain to improve spectral efficiency, coverage, and quality of service. It also describes how MIMO reduces co-channel interference. The document covers MIMO channel models and capacity results for different scenarios. It concludes by discussing how MIMO can be used to maximize diversity or throughput through different transmission techniques.
This document provides an overview of microwave communication. It discusses various topics related to microwave communication including possible media, manufacturers, advantages of microwave, characteristics, types of links and systems. It also covers topics such as line of sight requirements, wave propagation, multipath propagation, path loss, antenna types and gains. The document discusses concepts like fade margin, reliability and signal to noise ratio which are important in microwave system design. It provides examples of calculating free space loss and fresnel zone radius.
Intelligent Reflecting Surface (IRS) consists of passive elements that can reflect signals with adjustable phase shifts to maximize SNR through passive beamforming. IRS reflects signals in a controlled manner for improved communication without requiring transmission power. Key challenges include passive beamforming under power constraints and joint active/passive beamforming in multipath environments. Research directions include developing high-quality reflecting surfaces, RF propagation control, and optimizing IRS-enhanced wireless networks.
This document discusses diversity techniques for wireless communication. It begins by describing how wireless communication channels suffer from impairments like fading that degrade system performance. It then explains that diversity techniques address this issue by providing multiple replicas of transmitting signals over different fading channels to a receiver. This reduces the probability that all signals will fade simultaneously. The document outlines different types of diversity techniques and emphasizes that spatial diversity using multiple transmitting and receiving antennas is most popular as it improves performance without requiring extra power or bandwidth. It also discusses diversity combining methods used at receivers to optimize the received signal-to-noise ratio by collecting and combining unfaded signals from different branches.
This document discusses mobile radio propagation and related concepts. It begins with an outline of topics including speed, wavelength, frequency, propagation mechanisms, propagation effects, path loss, fading, Doppler shift, and delay spread. It then provides more detailed explanations and examples of these key concepts. The document explains that radio signals can propagate through reflection, diffraction, and scattering mechanisms. It also discusses how path loss increases with distance and frequency in various environments. The different types of fading, including slow and fast fading, are defined. Doppler shift and delay spread caused by signal reflections are also covered.
This document discusses different types of small scale fading in wireless communication based on time delay spread and Doppler spread. There are four main types of fading: flat fading, frequency selective fading, fast fading, and slow fading. Flat fading occurs when the bandwidth of the signal is less than the bandwidth of the channel and the delay spread is less than the symbol period. Frequency selective fading occurs when the bandwidth of the signal is greater than the bandwidth of the channel and the delay spread is greater than the symbol period. Fast fading occurs when there is a high Doppler spread and the coherence time is less than the symbol period. Slow fading occurs when there is a low Doppler spread and the coherence time is greater than the symbol period.
Microwave radio networks have several advantages over other network technologies including rapid deployment, flexibility, and lower costs. Common network architectures include spur, star, ring, and mesh configurations. Microwave propagation is affected by factors such as refraction, reflection, fading, and the environment. Careful network planning includes considerations for line of sight analysis, frequency selection, link engineering, and reliability predictions to ensure quality of service.
Small scale fading, also known as fading, describes the rapid fluctuations of signal amplitude and phase over short periods of time. It is caused by interference between multiple versions of a transmitted signal that take different paths to the receiver. This can result in changes to amplitude, phase, and time of arrival depending on factors like multipath propagation, Doppler shifts from mobile speed, movement of surrounding objects, and the signal bandwidth.
Wireless communication systems are impacted by fading effects that cause fluctuations in signal strength. Fading occurs due to multipath propagation which results in multiple versions of the transmitted signal reaching the receiver at different times. This can cause either flat or frequency selective fading depending on the delay spread. Modulation techniques like BPSK can be used to combat fading. Simulation of a Rayleigh fading channel, which occurs when there is no dominant signal path, showed that it significantly impacts the bit error rate of a BPSK modulated signal. Future work could explore additional modulation techniques and integrating the model into a network simulator.
This document provides an overview of key concepts in radio frequency (RF) technology for wireless communication systems. It defines terms like dBm for measuring power, and modulation schemes like amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK) for encoding digital signals onto radio carriers. The document also outlines considerations for selecting an appropriate low-power wireless solution, including radio spectrum and network types.
This document discusses various wireless propagation channels including free space propagation, reflection, scattering, and diffraction. It covers reflection propagation mechanisms such as reflection from dielectrics and conductors. Reflection coefficients and Snell's law are explained. Models for reflection, including the two-ray ground reflection model, are provided. Diffraction models like knife-edge diffraction and multiple knife-edge diffraction using methods like Bollington's method are summarized. Scattering models including Kirchoff's theory and perturbation theory are covered. Common fading models for mobile radio like Rayleigh, Rician, and Doppler shift models are described. Finally, different types of wireless channels including time-selective, frequency-selective, general, and WSSUS channels are classified
The document discusses various propagation mechanisms that affect radio signals, including reflection, diffraction, scattering, and their effects on signal strength over distance. It also covers propagation models like free space path loss, two-ray ground reflection model, and log-distance path loss for estimating average received signal power at a given distance. Fresnel zones and knife-edge diffraction are explained as factors in signal propagation around obstructions. Log-normal shadowing is described as a statistical model to account for variations from the average path loss.
1) The document discusses small-scale fading in mobile radio propagation. Small-scale fading is caused by multipath propagation and describes rapid fluctuations in a radio signal over a short time period or travel distance.
2) It introduces the impulse response model used to model multipath channels. The received signal is a combination of multipath components that arrive at different times with different amplitudes and phases.
3) It discusses parameters used to characterize mobile multipath channels including mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time. These parameters describe the time dispersion and time-varying nature of the channel.
Frii's equation models free space path loss and predicts the amount of power (Pr) that can be received by an antenna at a distance D from the transmitting antenna. The equation is:
Pr = Pt * Gt * Gr * λ2 / (4πD)2 * L
Where Pt is the transmitted power, Gt and Gr are the gains of the transmitting and receiving antennas, λ is the wavelength, D is the distance between antennas, and L accounts for transmission losses. According to the model, received power decays quadratically with distance, and factors like antenna gain and wavelength affect reception levels.
This document discusses the concept of diffraction as it relates to wireless communication. It explains that diffraction allows radio signals to propagate behind obstacles between a transmitter and receiver. It presents Huygen's principle, which states that each point on a wavefront can be considered a secondary source of wavelets. These wavelets combine to form a new wavefront. The document also covers knife-edge diffraction geometry and how to calculate the excess path length and phase difference between the diffracted and direct paths. It defines Fresnel zones and introduces the Fresnel zone diffraction parameter used to determine whether interference will be constructive or destructive. Additionally, it explains diffraction loss that occurs when secondary waves are blocked, resulting in only partial energy being diffract
The document discusses intelligent reflecting surfaces (IRS) which consist of passive elements that can reflect signals with adjustable phase shifts. This allows IRS to maximize SNR by passive beamforming. The key points are:
1. An IRS-assisted wireless network model is presented with an IRS containing N reflecting elements, a base station with M antennas, and K users.
2. The mathematical model expresses the received signal at each user as the direct path plus the IRS-aided path, with the reflection coefficient matrix at the IRS adjusting the phase shifts.
3. Design aspects of IRS include estimating the channel state information between the base station/IRS and IRS/users to optimize active/passive beamforming for maximizing
The document discusses different techniques to mitigate fading in wireless channels. It describes slow flat fading, frequency selective fading, and fast fading. To mitigate slow flat fading, the document discusses diversity which uses multiple independent fading paths. It explains different types of diversity including space, frequency, and time diversity. It also discusses diversity combining techniques such as selection, equal gain, and maximal ratio combining which combine signals from multiple diversity paths. The document aims to explain how to combat different types of fading in wireless channels.
The document discusses parameters for planning and designing line-of-sight microwave communication links, including path loss calculations. It covers topics like survey requirements, link budget calculations, transmission concepts, tower heights, earth bulge, fresnel zones, frequency assignments and limitations of line-of-sight systems. Key aspects addressed include determining tower heights to clear obstructions along the signal path based on factors like frequency, distance, earth curvature and fresnel zone radius.
This document provides training materials on calculating wireless link budgets to determine the feasibility and optimal configuration of radio links. It defines key concepts like free space loss, link budget, antenna gain and Fresnel zone. An example link budget calculation is shown for a 5km link. It also introduces the Radio Mobile software tool, which can automatically simulate radio links and calculate the required Fresnel zone clearance by considering terrain profiles. The document concludes with an example of using Radio Mobile to analyze a potential link in Chuuk and poses questions about configuring the masts, transmit power and antennas.
Loss of strength, A periodic reduction in the received strength of a radio transmission.
This is about the phenomenon of loss of signal in telecommunications.Fading refers to the
time variation of the received signal power caused by changes in the transmission medium or path.
This document discusses mobile radio propagation and includes the following key points:
- It describes different types of radio waves and frequency bands used in mobile communications. Propagation mechanisms like reflection, diffraction and scattering are also covered.
- Path loss models for free space, urban, suburban and open areas are presented. Higher path loss is observed in urban versus open areas.
- Slow fading relates to long-term signal strength variations while fast fading involves short-term fluctuations. Slow fading is modeled by log-normal distribution and fast fading by Rayleigh or Rician distributions depending on presence of line of sight.
- Characteristics of fast fading such as level crossing rate and fading rate are defined.
This document discusses mobile radio propagation and includes the following key points:
- It outlines different radio frequency bands and propagation mechanisms including reflection, diffraction, and scattering.
- It describes various propagation effects like free space propagation, land propagation, and path loss which increases with distance and frequency.
- It explains slow fading caused by shadowing and fast fading caused by multipath propagation, and the Rayleigh and Rician distributions used to model fast fading.
- It discusses metrics used to characterize fast fading like level crossing rate, fading rate, and depth of fading.
The document provides an overview of MIMO (multiple-input multiple-output) systems in wireless communications. It discusses how MIMO can provide array gain, diversity gain, and multiplexing gain to improve spectral efficiency, coverage, and quality of service. It also describes how MIMO reduces co-channel interference. The document covers MIMO channel models and capacity results for different scenarios. It concludes by discussing how MIMO can be used to maximize diversity or throughput through different transmission techniques.
This document provides an overview of microwave communication. It discusses various topics related to microwave communication including possible media, manufacturers, advantages of microwave, characteristics, types of links and systems. It also covers topics such as line of sight requirements, wave propagation, multipath propagation, path loss, antenna types and gains. The document discusses concepts like fade margin, reliability and signal to noise ratio which are important in microwave system design. It provides examples of calculating free space loss and fresnel zone radius.
Intelligent Reflecting Surface (IRS) consists of passive elements that can reflect signals with adjustable phase shifts to maximize SNR through passive beamforming. IRS reflects signals in a controlled manner for improved communication without requiring transmission power. Key challenges include passive beamforming under power constraints and joint active/passive beamforming in multipath environments. Research directions include developing high-quality reflecting surfaces, RF propagation control, and optimizing IRS-enhanced wireless networks.
This document discusses diversity techniques for wireless communication. It begins by describing how wireless communication channels suffer from impairments like fading that degrade system performance. It then explains that diversity techniques address this issue by providing multiple replicas of transmitting signals over different fading channels to a receiver. This reduces the probability that all signals will fade simultaneously. The document outlines different types of diversity techniques and emphasizes that spatial diversity using multiple transmitting and receiving antennas is most popular as it improves performance without requiring extra power or bandwidth. It also discusses diversity combining methods used at receivers to optimize the received signal-to-noise ratio by collecting and combining unfaded signals from different branches.
This document discusses mobile radio propagation and related concepts. It begins with an outline of topics including speed, wavelength, frequency, propagation mechanisms, propagation effects, path loss, fading, Doppler shift, and delay spread. It then provides more detailed explanations and examples of these key concepts. The document explains that radio signals can propagate through reflection, diffraction, and scattering mechanisms. It also discusses how path loss increases with distance and frequency in various environments. The different types of fading, including slow and fast fading, are defined. Doppler shift and delay spread caused by signal reflections are also covered.
This document discusses different types of small scale fading in wireless communication based on time delay spread and Doppler spread. There are four main types of fading: flat fading, frequency selective fading, fast fading, and slow fading. Flat fading occurs when the bandwidth of the signal is less than the bandwidth of the channel and the delay spread is less than the symbol period. Frequency selective fading occurs when the bandwidth of the signal is greater than the bandwidth of the channel and the delay spread is greater than the symbol period. Fast fading occurs when there is a high Doppler spread and the coherence time is less than the symbol period. Slow fading occurs when there is a low Doppler spread and the coherence time is greater than the symbol period.
Microwave radio networks have several advantages over other network technologies including rapid deployment, flexibility, and lower costs. Common network architectures include spur, star, ring, and mesh configurations. Microwave propagation is affected by factors such as refraction, reflection, fading, and the environment. Careful network planning includes considerations for line of sight analysis, frequency selection, link engineering, and reliability predictions to ensure quality of service.
Small scale fading, also known as fading, describes the rapid fluctuations of signal amplitude and phase over short periods of time. It is caused by interference between multiple versions of a transmitted signal that take different paths to the receiver. This can result in changes to amplitude, phase, and time of arrival depending on factors like multipath propagation, Doppler shifts from mobile speed, movement of surrounding objects, and the signal bandwidth.
Wireless communication systems are impacted by fading effects that cause fluctuations in signal strength. Fading occurs due to multipath propagation which results in multiple versions of the transmitted signal reaching the receiver at different times. This can cause either flat or frequency selective fading depending on the delay spread. Modulation techniques like BPSK can be used to combat fading. Simulation of a Rayleigh fading channel, which occurs when there is no dominant signal path, showed that it significantly impacts the bit error rate of a BPSK modulated signal. Future work could explore additional modulation techniques and integrating the model into a network simulator.
This document provides an overview of key concepts in radio frequency (RF) technology for wireless communication systems. It defines terms like dBm for measuring power, and modulation schemes like amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK) for encoding digital signals onto radio carriers. The document also outlines considerations for selecting an appropriate low-power wireless solution, including radio spectrum and network types.
This document discusses various wireless propagation channels including free space propagation, reflection, scattering, and diffraction. It covers reflection propagation mechanisms such as reflection from dielectrics and conductors. Reflection coefficients and Snell's law are explained. Models for reflection, including the two-ray ground reflection model, are provided. Diffraction models like knife-edge diffraction and multiple knife-edge diffraction using methods like Bollington's method are summarized. Scattering models including Kirchoff's theory and perturbation theory are covered. Common fading models for mobile radio like Rayleigh, Rician, and Doppler shift models are described. Finally, different types of wireless channels including time-selective, frequency-selective, general, and WSSUS channels are classified
The document discusses various propagation mechanisms that affect radio signals, including reflection, diffraction, scattering, and their effects on signal strength over distance. It also covers propagation models like free space path loss, two-ray ground reflection model, and log-distance path loss for estimating average received signal power at a given distance. Fresnel zones and knife-edge diffraction are explained as factors in signal propagation around obstructions. Log-normal shadowing is described as a statistical model to account for variations from the average path loss.
1) The document discusses small-scale fading in mobile radio propagation. Small-scale fading is caused by multipath propagation and describes rapid fluctuations in a radio signal over a short time period or travel distance.
2) It introduces the impulse response model used to model multipath channels. The received signal is a combination of multipath components that arrive at different times with different amplitudes and phases.
3) It discusses parameters used to characterize mobile multipath channels including mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time. These parameters describe the time dispersion and time-varying nature of the channel.
Frii's equation models free space path loss and predicts the amount of power (Pr) that can be received by an antenna at a distance D from the transmitting antenna. The equation is:
Pr = Pt * Gt * Gr * λ2 / (4πD)2 * L
Where Pt is the transmitted power, Gt and Gr are the gains of the transmitting and receiving antennas, λ is the wavelength, D is the distance between antennas, and L accounts for transmission losses. According to the model, received power decays quadratically with distance, and factors like antenna gain and wavelength affect reception levels.
This document discusses the concept of diffraction as it relates to wireless communication. It explains that diffraction allows radio signals to propagate behind obstacles between a transmitter and receiver. It presents Huygen's principle, which states that each point on a wavefront can be considered a secondary source of wavelets. These wavelets combine to form a new wavefront. The document also covers knife-edge diffraction geometry and how to calculate the excess path length and phase difference between the diffracted and direct paths. It defines Fresnel zones and introduces the Fresnel zone diffraction parameter used to determine whether interference will be constructive or destructive. Additionally, it explains diffraction loss that occurs when secondary waves are blocked, resulting in only partial energy being diffract
The document discusses intelligent reflecting surfaces (IRS) which consist of passive elements that can reflect signals with adjustable phase shifts. This allows IRS to maximize SNR by passive beamforming. The key points are:
1. An IRS-assisted wireless network model is presented with an IRS containing N reflecting elements, a base station with M antennas, and K users.
2. The mathematical model expresses the received signal at each user as the direct path plus the IRS-aided path, with the reflection coefficient matrix at the IRS adjusting the phase shifts.
3. Design aspects of IRS include estimating the channel state information between the base station/IRS and IRS/users to optimize active/passive beamforming for maximizing
The document discusses different techniques to mitigate fading in wireless channels. It describes slow flat fading, frequency selective fading, and fast fading. To mitigate slow flat fading, the document discusses diversity which uses multiple independent fading paths. It explains different types of diversity including space, frequency, and time diversity. It also discusses diversity combining techniques such as selection, equal gain, and maximal ratio combining which combine signals from multiple diversity paths. The document aims to explain how to combat different types of fading in wireless channels.
The document discusses parameters for planning and designing line-of-sight microwave communication links, including path loss calculations. It covers topics like survey requirements, link budget calculations, transmission concepts, tower heights, earth bulge, fresnel zones, frequency assignments and limitations of line-of-sight systems. Key aspects addressed include determining tower heights to clear obstructions along the signal path based on factors like frequency, distance, earth curvature and fresnel zone radius.
This document provides training materials on calculating wireless link budgets to determine the feasibility and optimal configuration of radio links. It defines key concepts like free space loss, link budget, antenna gain and Fresnel zone. An example link budget calculation is shown for a 5km link. It also introduces the Radio Mobile software tool, which can automatically simulate radio links and calculate the required Fresnel zone clearance by considering terrain profiles. The document concludes with an example of using Radio Mobile to analyze a potential link in Chuuk and poses questions about configuring the masts, transmit power and antennas.
Loss of strength, A periodic reduction in the received strength of a radio transmission.
This is about the phenomenon of loss of signal in telecommunications.Fading refers to the
time variation of the received signal power caused by changes in the transmission medium or path.
This document discusses mobile radio propagation and includes the following key points:
- It describes different types of radio waves and frequency bands used in mobile communications. Propagation mechanisms like reflection, diffraction and scattering are also covered.
- Path loss models for free space, urban, suburban and open areas are presented. Higher path loss is observed in urban versus open areas.
- Slow fading relates to long-term signal strength variations while fast fading involves short-term fluctuations. Slow fading is modeled by log-normal distribution and fast fading by Rayleigh or Rician distributions depending on presence of line of sight.
- Characteristics of fast fading such as level crossing rate and fading rate are defined.
This document discusses mobile radio propagation and includes the following key points:
- It outlines different radio frequency bands and propagation mechanisms including reflection, diffraction, and scattering.
- It describes various propagation effects like free space propagation, land propagation, and path loss which increases with distance and frequency.
- It explains slow fading caused by shadowing and fast fading caused by multipath propagation, and the Rayleigh and Rician distributions used to model fast fading.
- It discusses metrics used to characterize fast fading like level crossing rate, fading rate, and depth of fading.
This document discusses mobile radio propagation and related concepts. It covers topics such as speed, wavelength and frequency of radio signals, propagation mechanisms including reflection, diffraction and scattering. It also discusses radio frequency bands, propagation effects, path loss models for different environments including free space, urban, suburban and open areas. The document further explains fading effects including slow fading due to shadowing and fast fading due to multipath, as well as Doppler shift experienced due to relative motion between transmitter and receiver.
Mobile radio propagation models are derived using empirical and analytical methods to account for all known and unknown propagation factors. Signal strength must be strong enough for quality but not too strong to cause interference. Fading can disrupt signals and cause errors. Path loss models predict received signal level as a function of distance and are used to estimate signal-to-noise ratio. Path loss includes propagation, absorption, diffraction, and other losses. Large-scale models describe mean path loss over hundreds of meters while small-scale models characterize rapid fluctuations over small distances.
This document provides an introduction to key concepts in wireless communication systems. It outlines the main elements of a wireless system including the transmitter, frequency spectrum, modulation, antenna, propagation medium, and receiver. It also discusses wireless history, services, frequency bands, antenna characteristics, signal attenuation and noise. Common modulation techniques like AM, FM, ASK, FSK, PSK and QAM are introduced. The document also covers concepts of multipath propagation, signal-to-noise ratio, and multiplexing methods including TDM, FDM and CDMA.
The document discusses key aspects of wireless communication reference models including:
1. It describes the layers of the reference model from the physical layer up to the application layer and their main functions.
2. It covers topics like frequency ranges used for wireless transmission, common modulation techniques, and effects of signal propagation like multipath propagation.
3. It discusses technologies and standards used for wireless networks and regulations set by organizations like ITU.
This document provides information about microwave communication systems. It defines microwave communication as a high radio frequency link designed to provide signal connection between two points. It operates in the 2-60 GHz band and can be analog or digital. Short, medium, and long haul systems exist based on distance and frequency used. The document discusses advantages like increased gain and reliability, as well as disadvantages like limitations in circuit design at high frequencies. It provides formulas for analyzing microwave links, including free space loss, antenna gain, system gain, and more. Worked examples of link calculations are also included.
Introduction to basics of wireless networks such as
• Radio waves & wireless signal encoding techniques
• Wireless networking issues & constraints
• Wireless internetworking devices
This document discusses various topics related to antennas and propagation, including:
- The basic functions of antennas for transmission and reception of signals
- Types of radiation and reception patterns that characterize antenna performance
- Common types of antennas like dipole, vertical, and parabolic reflective antennas
- Factors that influence signal propagation over distance like free space loss, noise, multipath interference, and atmospheric effects
- Techniques to improve reliability like diversity combining, adaptive equalization, and forward error correction coding.
This document discusses MTI (Moving Target Indication) and pulse Doppler radars. It begins by explaining how clutter like land, sea, and weather can interfere with radar detection of targets. It then describes the Doppler effect which causes a shift in frequency when the radar or target is in motion, allowing CW radars to detect moving targets. MTI radars use a technique called pulse cancellation to remove stationary clutter and detect moving targets. Pulse Doppler radars also use Doppler shift but have a high pulse repetition frequency which avoids ambiguities. The document discusses limitations of CW and MTI radars and techniques to overcome them like using multiple frequencies or pulse repetition frequencies. It includes diagrams of radar systems and equations for Doppler shift.
Lecture on mobile radio environme, nt.pptNanaAgyeman13
The document discusses reasons why wireless signals are difficult to send and receive. It explains that radio channels are random due to multipath propagation from reflections, diffractions, and scattering caused by buildings, foliage and terrain. This creates interference between signals, shadowing effects, and small-scale fading. Additional challenges include interference between users and service providers. Accurately characterizing wireless channels requires statistical analysis and field measurements due to their unpredictable nature.
1) The document discusses small-scale fading in mobile radio channels caused by multipath propagation. Multipath signals interfere constructively and destructively, causing rapid fluctuations in received signal strength over small distances.
2) Key parameters that characterize multipath channels are delay spread (στ), coherence bandwidth (Bc), Doppler spread (BD), and coherence time (Tc). Delay spread and coherence bandwidth describe time dispersion, while Doppler spread and coherence time describe frequency dispersion from mobility.
3) There are different types of fading depending on how a signal's bandwidth compares to these channel parameters. Flat fading occurs when the signal bandwidth is narrow compared to the channel bandwidth, preserving the signal's spectral properties.
- The document discusses wireless channel propagation and fading. It covers topics like large-scale fading (path loss and shadowing), small-scale fading (time-selective and frequency-selective fading), and statistical characterization of fading channels.
- Small-scale fading is caused by multipath propagation and results in rapid fluctuations in the strength of the received signal over short periods of time or travel distances. It can be time-selective or frequency-selective depending on delay spread and Doppler spread.
- Common distributions for modeling fading amplitudes are Rayleigh for non-line-of-sight environments and Rician when there is a dominant line-of-sight path. The document presents models for generating both Rayleigh and Rician fading
C cf radio propagation theory and propagation modelsTempus Telcosys
The radio propagation theory is an important lesson in the radio communication curriculum. This lesson answers the following questions:
How are radio waves transmitted from one antenna to the other antenna?
What features does the radio wave have during the propagation? Which factors affect the propagation distance?
What fruits are achieved by predecessors in the radio wave propagation theory? How to apply the theory to practice?
Chapter 1 Radio Propagation Theory
Chapter 2 Radio Propagation Environment
Chapter 3 Radio Propagation Models
The document discusses MTI (Moving Target Indication) and pulse Doppler radars. It explains that MTI radars use techniques like delay line cancellation to eliminate echoes from stationary clutter and detect moving targets. Pulse Doppler radars employ the Doppler shift caused by target motion to detect targets. Key differences are noted - MTI radars have no range ambiguities but Doppler ambiguities, while pulse Doppler radars have the opposite problem. Blind speeds, limitations of CW radar, and techniques to overcome issues like flicker noise and lack of isolation are also covered. Applications of CW radar like speed measurement are mentioned.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), free space loss, noise, multipath, and techniques to mitigate signal degradation like diversity and error correction.
This document provides an overview of key concepts in antennas and propagation. It defines an antenna as a device that transmits or receives electromagnetic waves. It describes common antenna types like dipoles and parabolic reflectors. It also covers topics like radiation patterns, antenna gain, propagation modes (ground wave, sky wave, line-of-sight), factors that affect signal strength over distance like free space loss and multipath, and techniques to mitigate noise and fading like diversity and error correction.
1. Radio propagation involves mechanisms like reflection, diffraction, scattering that affect the strength of the radio signal over distance.
2. Reflection occurs when the radio wave impinges on objects larger than the wavelength like buildings, walls. Diffraction allows signals to propagate beyond obstacles. Scattering occurs from objects smaller than the wavelength.
3. Propagation models like free space and two-ray ground reflection are used to predict signal strength over large distances. Factors like Fresnel zones and knife-edge diffraction also impact signal propagation around obstacles.
The document defines terms and concepts related to electromagnetic spectrum, radio wave propagation, modulation techniques, radar fundamentals, and signals intelligence collection. It describes the frequency bands of the electromagnetic spectrum and their common uses. It also defines key terms like frequency, wavelength, modulation, demodulation, bandwidth, and propagation effects in the atmosphere. Modulation techniques like AM, FM, USB/LSB, and CW are explained. Radar fundamentals covered include terms like PRF, PW, scan rate, bearing, and the functions of air search, surface search, and fire control radars. The document distinguishes between operational intelligence (OPELINT) and technical intelligence (TECHELINT) collection.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Immersive Learning That Works: Research Grounding and Paths ForwardLeonel Morgado
We will metaverse into the essence of immersive learning, into its three dimensions and conceptual models. This approach encompasses elements from teaching methodologies to social involvement, through organizational concerns and technologies. Challenging the perception of learning as knowledge transfer, we introduce a 'Uses, Practices & Strategies' model operationalized by the 'Immersive Learning Brain' and ‘Immersion Cube’ frameworks. This approach offers a comprehensive guide through the intricacies of immersive educational experiences and spotlighting research frontiers, along the immersion dimensions of system, narrative, and agency. Our discourse extends to stakeholders beyond the academic sphere, addressing the interests of technologists, instructional designers, and policymakers. We span various contexts, from formal education to organizational transformation to the new horizon of an AI-pervasive society. This keynote aims to unite the iLRN community in a collaborative journey towards a future where immersive learning research and practice coalesce, paving the way for innovative educational research and practice landscapes.
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).