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Evaluation progresion path loss model
This document describes research evaluating a terrain-sensitive radio propagation path loss model based on the Geometrical Theory of Diffraction (GTD). The research was funded by the Southeastern Conference for Electrical Engineering Education. The GTD model was modified to account for finite conductivity and local surface roughness of terrain. Measured path loss data was compared to GTD modeled data to evaluate the model's prediction performance capabilities over various distances and frequencies. The results showed GTD is a feasible method for predicting short-range propagation path losses.
Path loss models comparation in radio mobile communications
path loss models comparation in radio mobile communications
Path loss model frin indoor wireless communication
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise boosts blood flow and levels of neurotransmitters and endorphins which elevate and stabilize mood.
1206 gioi thieu iso27001 2005-b&m
Xây dựng hệ thống an toàn thông tin dựa trên tiêu chuẩn ISO/IEC 270001:2005 - Hệ thống quản lý an toàn thông tin (ISMS)
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Evaluation progresion path loss model
This document describes research evaluating a terrain-sensitive radio propagation path loss model based on the Geometrical Theory of Diffraction (GTD). The research was funded by the Southeastern Conference for Electrical Engineering Education. The GTD model was modified to account for finite conductivity and local surface roughness of terrain. Measured path loss data was compared to GTD modeled data to evaluate the model's prediction performance capabilities over various distances and frequencies. The results showed GTD is a feasible method for predicting short-range propagation path losses.
Path loss models comparation in radio mobile communications
path loss models comparation in radio mobile communications
Path loss model frin indoor wireless communication
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise boosts blood flow and levels of neurotransmitters and endorphins which elevate and stabilize mood.
1206 gioi thieu iso27001 2005-b&m
Xây dựng hệ thống an toàn thông tin dựa trên tiêu chuẩn ISO/IEC 270001:2005 - Hệ thống quản lý an toàn thông tin (ISMS)
Plugin modul 1-e
The document provides an overview of UMTS (Universal Mobile Telecommunications System), the 3G mobile communication standard. It discusses trends driving the need for UMTS, including increasing data usage, integration of technologies, and limitations of 2G systems. The document also outlines key demands on UMTS, the standardization process, and the staged development of UMTS from GSM networks to the new UMTS network architecture using W-CDMA and other CDMA technologies over dedicated frequency bands.
Wireless security
This document provides information on securing wireless networks both at home and in public places. It discusses threats like piggybacking, wardriving, and unauthorized access that can occur if a wireless network is not properly secured. The document then gives steps to secure a home wireless network, such as encrypting the network traffic, changing default passwords, and keeping the wireless access point software updated. It also provides tips for safely using public wireless networks, like only connecting to trusted networks, using a VPN if possible, and disabling file sharing.
Propagation measurements and models for wireless channels
This document discusses wireless propagation measurements and channel models. It begins by describing the importance of understanding propagation for wireless communication systems and outlines different modeling approaches. It then discusses key propagation parameters like path loss, multipath delay spread, and measurements used to characterize wireless channels. Specific propagation mechanisms like reflection, diffraction and scattering are also covered. The document concludes by examining outdoor and indoor propagation environments and considerations for modeling different scenarios.
Plugin roelens2006
This paper presents a new empirical path loss model for wireless communication at 2.4 GHz above simulated human tissue. The model is valid for dipole antennas placed up to 5 cm above flat phantom tissue simulating muscle or brain, and for distances up to 40 cm. Simulation and measurement results showed excellent agreement. The study found that antenna height has a major influence on path loss, with path loss dropping quickly as height decreases. Models were developed to estimate path loss as a function of antenna height and distance for both muscle and brain tissue.
Path loss prediction
This summary provides an overview of the key points from the document:
1) The document presents the use of General Regression Neural Networks (GRNN) to predict propagation path loss in an urban environment based on measurements taken in Kavala, Greece.
2) Two neural network models are studied - one for path loss prediction and another using error control. Their performance is compared to measured path loss values based on error metrics.
3) For line-of-sight predictions, the GRNN model achieves better performance than empirical models due to using multiple input parameters and generalization. For non-line-of-sight, a third GRNN model including street orientation has the lowest error rates.
Path loss models
This document summarizes wireless communication path loss models. It describes the basic propagation mechanisms of reflection, diffraction, and scattering that impact signal transmission. Free space loss is defined, showing the relationship between received and transmitted power over distance. Ground reflection and the two-path model are explained, including the impact of distance on received power. General ray tracing and simplified path loss models are introduced. Finally, log-normal shadowing is summarized as modeling additional loss through a Gaussian random variable.
Path loss models for air to-ground radio
This document proposes new statistical path loss models for air-to-ground radio channels in urban environments. It derives models based on ray-tracing simulations of radio propagation between airborne platforms and ground terminals in a 3D model of Bristol, UK. The models represent path loss and shadowing as a function of elevation angle rather than distance. Results show air-to-ground channels have advantages over peer-to-peer channels in urban areas, with line-of-sight probability decreasing less sharply with distance. Path loss is modeled separately for line-of-sight, obstructed line-of-sight, and non-line-of-sight conditions using equations involving elevation angle and frequency. Shadowing is found to follow a zero
Path loss models comparation in radio mobile communications
The document compares different path loss models used in radio mobile communications. It discusses statistical models like the Okumura-Hata model which is based on empirical data from Tokyo and considers factors like frequency, base station height, mobile height, and distance. It also examines physical models like Walfish-Ikegami/COST-231 which take into account free space loss, diffraction loss, and loss from rooftops. While physical models can achieve more accuracy by applying electromagnetic laws, statistical models are easier to use without needing geographic data but have limited validity ranges.
Path loss modeling of mobile radio communication in urban areas
This document presents a numerical path loss model for mobile radio communication in urban areas using the Uniform Theory of Diffraction (UTD). The model considers various propagation paths around buildings and compares computed results at 2.154GHz and 835MHz to existing models, finding excellent agreement. Computed losses are shown to decrease with lower frequency and increase with distance from the base station, while changing in complex ways with mobile position due to multipath effects. The model provides a simple and reliable way to predict path losses in both line-of-sight and non-line-of-sight environments.
Path loss exponent estimation
The document describes three distributed algorithms for estimating the path loss exponent (PLE) in large wireless networks. The first algorithm uses the mean interference value and assumes knowledge of the network density. The second and third algorithms are based on outage probabilities and connectivity properties, respectively, and do not require knowledge of density or fading parameters. Simulation results demonstrate the performance of the algorithms and quantify the estimation error. The algorithms take into account interference, noise, and fading effects in wireless networks.
Path loss correction factor
This document discusses a study comparing path loss models for wireless communication in a suburban fringe area of India. Field measurements were taken of signal strength over distances from 1-5 km in the suburban city of Mehuwala. A path loss model was developed from the measured data that found the path loss increased at 26.7 dB per decade of distance. This was compared to the HATA model, which increased path loss at a rate of 34.26 dB per decade. The study found the measured model to have greater accuracy for this environment since models like HATA are designed for environments different than a typical Indian suburban city. Field measurements were determined to be needed to either correct existing models or develop new models tailored to specific environments.
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Plugin modul 1-e
The document provides an overview of UMTS (Universal Mobile Telecommunications System), the 3G mobile communication standard. It discusses trends driving the need for UMTS, including increasing data usage, integration of technologies, and limitations of 2G systems. The document also outlines key demands on UMTS, the standardization process, and the staged development of UMTS from GSM networks to the new UMTS network architecture using W-CDMA and other CDMA technologies over dedicated frequency bands.
Wireless security
This document provides information on securing wireless networks both at home and in public places. It discusses threats like piggybacking, wardriving, and unauthorized access that can occur if a wireless network is not properly secured. The document then gives steps to secure a home wireless network, such as encrypting the network traffic, changing default passwords, and keeping the wireless access point software updated. It also provides tips for safely using public wireless networks, like only connecting to trusted networks, using a VPN if possible, and disabling file sharing.
Propagation measurements and models for wireless channels
This document discusses wireless propagation measurements and channel models. It begins by describing the importance of understanding propagation for wireless communication systems and outlines different modeling approaches. It then discusses key propagation parameters like path loss, multipath delay spread, and measurements used to characterize wireless channels. Specific propagation mechanisms like reflection, diffraction and scattering are also covered. The document concludes by examining outdoor and indoor propagation environments and considerations for modeling different scenarios.
Plugin roelens2006
This paper presents a new empirical path loss model for wireless communication at 2.4 GHz above simulated human tissue. The model is valid for dipole antennas placed up to 5 cm above flat phantom tissue simulating muscle or brain, and for distances up to 40 cm. Simulation and measurement results showed excellent agreement. The study found that antenna height has a major influence on path loss, with path loss dropping quickly as height decreases. Models were developed to estimate path loss as a function of antenna height and distance for both muscle and brain tissue.
Path loss prediction
This summary provides an overview of the key points from the document:
1) The document presents the use of General Regression Neural Networks (GRNN) to predict propagation path loss in an urban environment based on measurements taken in Kavala, Greece.
2) Two neural network models are studied - one for path loss prediction and another using error control. Their performance is compared to measured path loss values based on error metrics.
3) For line-of-sight predictions, the GRNN model achieves better performance than empirical models due to using multiple input parameters and generalization. For non-line-of-sight, a third GRNN model including street orientation has the lowest error rates.
Path loss models
This document summarizes wireless communication path loss models. It describes the basic propagation mechanisms of reflection, diffraction, and scattering that impact signal transmission. Free space loss is defined, showing the relationship between received and transmitted power over distance. Ground reflection and the two-path model are explained, including the impact of distance on received power. General ray tracing and simplified path loss models are introduced. Finally, log-normal shadowing is summarized as modeling additional loss through a Gaussian random variable.
Path loss models for air to-ground radio
This document proposes new statistical path loss models for air-to-ground radio channels in urban environments. It derives models based on ray-tracing simulations of radio propagation between airborne platforms and ground terminals in a 3D model of Bristol, UK. The models represent path loss and shadowing as a function of elevation angle rather than distance. Results show air-to-ground channels have advantages over peer-to-peer channels in urban areas, with line-of-sight probability decreasing less sharply with distance. Path loss is modeled separately for line-of-sight, obstructed line-of-sight, and non-line-of-sight conditions using equations involving elevation angle and frequency. Shadowing is found to follow a zero
Path loss models comparation in radio mobile communications
The document compares different path loss models used in radio mobile communications. It discusses statistical models like the Okumura-Hata model which is based on empirical data from Tokyo and considers factors like frequency, base station height, mobile height, and distance. It also examines physical models like Walfish-Ikegami/COST-231 which take into account free space loss, diffraction loss, and loss from rooftops. While physical models can achieve more accuracy by applying electromagnetic laws, statistical models are easier to use without needing geographic data but have limited validity ranges.
Path loss modeling of mobile radio communication in urban areas
This document presents a numerical path loss model for mobile radio communication in urban areas using the Uniform Theory of Diffraction (UTD). The model considers various propagation paths around buildings and compares computed results at 2.154GHz and 835MHz to existing models, finding excellent agreement. Computed losses are shown to decrease with lower frequency and increase with distance from the base station, while changing in complex ways with mobile position due to multipath effects. The model provides a simple and reliable way to predict path losses in both line-of-sight and non-line-of-sight environments.
Path loss exponent estimation
The document describes three distributed algorithms for estimating the path loss exponent (PLE) in large wireless networks. The first algorithm uses the mean interference value and assumes knowledge of the network density. The second and third algorithms are based on outage probabilities and connectivity properties, respectively, and do not require knowledge of density or fading parameters. Simulation results demonstrate the performance of the algorithms and quantify the estimation error. The algorithms take into account interference, noise, and fading effects in wireless networks.
Path loss correction factor
This document discusses a study comparing path loss models for wireless communication in a suburban fringe area of India. Field measurements were taken of signal strength over distances from 1-5 km in the suburban city of Mehuwala. A path loss model was developed from the measured data that found the path loss increased at 26.7 dB per decade of distance. This was compared to the HATA model, which increased path loss at a rate of 34.26 dB per decade. The study found the measured model to have greater accuracy for this environment since models like HATA are designed for environments different than a typical Indian suburban city. Field measurements were determined to be needed to either correct existing models or develop new models tailored to specific environments.
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Propagation measurements and models for wireless channels
Propagation measurements and models for wireless channels
Path loss models comparation in radio mobile communications
Path loss models comparation in radio mobile communications
Path loss modeling of mobile radio communication in urban areas
Path loss modeling of mobile radio communication in urban areas