A Methodology to Predict the Impact of Substrate Noise in Analog/RF Systems

2009 ◽  
Vol 28 (11) ◽  
pp. 1613-1626 ◽  
Author(s):  
S. Bronckers ◽  
K. Scheir ◽  
G. Van der Plas ◽  
G. Vandersteen ◽  
Y. Rolain
Keyword(s):  
Substrate Noise ◽  
Rf Systems ◽  
The Impact

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

SIMULATION OF THERMAL NOISE IN SCALED MOSFETS

2002 ◽  
Vol 02 (02) ◽  
pp. L109-L116 ◽  
Author(s):  
SERGIO SPEDO ◽  
CLAUDIO FIEGNA
Keyword(s):  
Low Power ◽  
Thermal Noise ◽  
Gate Length ◽  
Noise Performance ◽  
Spectral Densities ◽  
Technology Scaling ◽  
Noise Parameters ◽  
Rf Systems ◽  
The Impact

In this work, hydrodynamic device simulations and a post-processor for the simulation of noise in MOSFETs are applied in order to evaluate the impact of scaling on the thermal noise of transistors representative of technologies with minimum gate length scaled from 0.25 μm down to 0.1 μm. The dependences on bias and technology scaling of the spectral densities of the equivalent drain- and induced gate-noise currents are anayzed in details. The effect of technology scaling on the two-port noise parameters of the intrinsic MOSFET is studied as well. The results of this work confirm that the transistor's noise performance tend to improve as the technology is scaled down, making CMOS a suitable technological option for the implementation of advanced low-power RF systems.

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

scholarly journals On the Design of Rate Adaptation for Relay-Assisted Satellite Hybrid FSO/RF Systems

2021 ◽  
Author(s):  
Hoang Le ◽  
Thang Nguyen
Keyword(s):  
Satellite Communication ◽  
Performance Metrics ◽  
Transmission Rate ◽  
Rate Adaptation ◽  
Spectrum Efficiency ◽  
Free Space Optical ◽  
Fixed Rate ◽  
Rf Systems ◽  
Average Transmission ◽  
The Impact

<p>This paper addresses the design of hybrid free-space optical/radio frequency (FSO/RF) systems for a high-altitude platform (HAP)-aided relaying satellite communication for mobile networks supported by unmanned aerial vehicle (UAV). While prior work primarily focused on fixed-rate design, which frequently switches between FSO and RF lead to reduce the system performance, we propose a rate adaptation design that gradually adjusts the data rate in each link when its channel state fluctuates. The proposed design's downlink performance is analyzed, taking into account many challenging issues, including beam spreading loss, cloud attenuation, statistical behaviors of the atmospheric turbulence in the dual-hop channel, and pointing misalignment due to the UAV hovering. Different performance metrics are analytically derived based on channel modelings, such as outage probability, average transmission rate, achievable spectrum efficiency, and average transmission rate. The numerical results quantitatively confirm the effectiveness of our proposed system under the impact of UAV hovering misalignment and atmospheric-related issues like clouds and turbulence. Finally, Monte-Carlo simulations validate the accuracy of theoretical results.</p>

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