1) Cell breathing is a technique used in CDMA networks to balance forward and reverse link handoff boundaries by adjusting pilot power levels between cells based on changes in reverse link interference.
2) When a cell becomes heavily loaded, cell breathing reduces its coverage area by lowering its pilot power, shedding some traffic to neighboring lightly loaded cells and relieving overload.
3) While this provides some capacity increase to the heavily loaded cell, it also reduces signal quality for users near the cell boundary and increases interference in neighboring cells. The overall benefits are limited and cell breathing can deteriorate network performance if used excessively.
The document describes a novel electrically small planar dipole antenna operating at 2.45 GHz. The antenna has extremely small dimensions of 11.2x5.1x1.575 mm, making it one of the smallest reported footprints at this frequency. Three matching approaches are studied to match the antenna's impedance to 50 ohms. Matching approach 1 has the highest efficiency of 87.4% and realized gain of 1.17 dBi. Approaches 2 and 3 have lower efficiencies around 40% due to increased surface currents from end-loading the dipole. The antenna is also modeled using an infinitesimal dipole model, which shows good agreement with simulations. Fabricated prototypes are presented for the three approaches
The downlink of a satellite circuit is the one in which the satellite is trans- mitting the signal and the earth station is receiving it.
The free space and other losses are calculated for the downlink frequency.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
Characteristic Comparison of U-Shaped Monopole and Complete Monopole AntennaIOSR Journals
A monopole antenna is a type of radio antenna formed by replacing one half of a dipole antenna with
a ground plane at right-angles to the remaining half. Monopoles may be used from a few hundred KHz through
several GHz in frequency and are commonly one-quarter of a wave length long, but may be shorter or longer.
Monopole antennas exhibit high gain and improved efficiency in a surprisingly small package. Monopole
antenna can be designed to exhibit wideband capabilities. The different available monopole antennas are dual
band printed monopole antenna, cross-slot monopole antenna, U-shaped monopole antenna, triangular shaped
monopole antenna and a wideband monopole antenna. This paper deals with the comparison obtained from the
results such as return loss, VSWR, current distribution, and the radiation pattern of simple U-shaped and
complete monopole antenna
The PEP-II B-Factory operated from 1999 to 2008, delivering luminosity to the BaBar experiment. It surpassed its design luminosity four-fold, reaching 1.21 x 1034 cm-2 s-1. A total of 557.4 fb-1 of luminosity was delivered to BaBar spanning five upsilon resonances. Continuous injection was implemented while BaBar took data, increasing average integrated luminosity by 40%. PEP-II set world records for stored beam current and exceeded all design parameters.
Circular antenna array has gained immense
popularity in the field of communications nowadays. It has
proved to be a better alternative over other types of antenna
array configuration due to its all-azimuth scan capability,
and a beam pattern which can be kept invariant. This paper is
basically concerned with the thinning of a large multiple
concentric circular ring arrays of uniformly excited isotropic
antennas based on Improved Particle Swarm Optimization
(IPSO) method. In this paper a 9 ringed Concentric Circular
Antenna Array (CCAA) with central element feeding is
considered. The computational results show that the number
of antenna array elements can be brought down from 279 to
147 with simultaneous reduction in Side Lobe Level of about
20 dB with a fixed half power beamwidth.
DESIGN AND ANALYSIS OF COMPACT UWB BAND PASS FILTERijeljournal
This paper presents design, implementation and analysis of an ultra-wideband (UWB) band-pass-filter using parallel-coupled microstrip line with defective ground plane and a uniform multi-mode resonator. The structure of the filter is designed on microwave substrate GML 1000 of dielectric constant 3.2 and height is 0.762 mm. Simulation is carried out by CST MSW software and optimized structure is fabricated. The frequency response is measured on vector analyzer and measured results show close approximation with simulation results. In this article modeling of the proposed filter is also reported. The electric model of the filter is analyzed by circuit theory and MATLAB. This model is validated by comparing the results with the CST simulation and VNA measured results. This filter is compact in size of dimension 30˟1.87 mm2 may be useful for modern wireless application of communication.
This document summarizes a presentation about vertical cavity surface emitting lasers (VCSELs). It begins with an introduction to VCSELs and their history. It then discusses VCSEL structure, including distributed Bragg reflectors (DBRs) for optical and current confinement, and rate equations that describe VCSEL characteristics. Continuous wave performance is examined through current-light output curves. Applications include optical fiber data transmission, displays, and sensors. Later sections provide examples of single-mode oxide-confined VCSELs for printers and sensors, electrically pumped GaSb-based VCSELs, and all-optical flip-flop operation using polarization bistable VCSELs.
The document describes a novel electrically small planar dipole antenna operating at 2.45 GHz. The antenna has extremely small dimensions of 11.2x5.1x1.575 mm, making it one of the smallest reported footprints at this frequency. Three matching approaches are studied to match the antenna's impedance to 50 ohms. Matching approach 1 has the highest efficiency of 87.4% and realized gain of 1.17 dBi. Approaches 2 and 3 have lower efficiencies around 40% due to increased surface currents from end-loading the dipole. The antenna is also modeled using an infinitesimal dipole model, which shows good agreement with simulations. Fabricated prototypes are presented for the three approaches
The downlink of a satellite circuit is the one in which the satellite is trans- mitting the signal and the earth station is receiving it.
The free space and other losses are calculated for the downlink frequency.
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
Characteristic Comparison of U-Shaped Monopole and Complete Monopole AntennaIOSR Journals
A monopole antenna is a type of radio antenna formed by replacing one half of a dipole antenna with
a ground plane at right-angles to the remaining half. Monopoles may be used from a few hundred KHz through
several GHz in frequency and are commonly one-quarter of a wave length long, but may be shorter or longer.
Monopole antennas exhibit high gain and improved efficiency in a surprisingly small package. Monopole
antenna can be designed to exhibit wideband capabilities. The different available monopole antennas are dual
band printed monopole antenna, cross-slot monopole antenna, U-shaped monopole antenna, triangular shaped
monopole antenna and a wideband monopole antenna. This paper deals with the comparison obtained from the
results such as return loss, VSWR, current distribution, and the radiation pattern of simple U-shaped and
complete monopole antenna
The PEP-II B-Factory operated from 1999 to 2008, delivering luminosity to the BaBar experiment. It surpassed its design luminosity four-fold, reaching 1.21 x 1034 cm-2 s-1. A total of 557.4 fb-1 of luminosity was delivered to BaBar spanning five upsilon resonances. Continuous injection was implemented while BaBar took data, increasing average integrated luminosity by 40%. PEP-II set world records for stored beam current and exceeded all design parameters.
Circular antenna array has gained immense
popularity in the field of communications nowadays. It has
proved to be a better alternative over other types of antenna
array configuration due to its all-azimuth scan capability,
and a beam pattern which can be kept invariant. This paper is
basically concerned with the thinning of a large multiple
concentric circular ring arrays of uniformly excited isotropic
antennas based on Improved Particle Swarm Optimization
(IPSO) method. In this paper a 9 ringed Concentric Circular
Antenna Array (CCAA) with central element feeding is
considered. The computational results show that the number
of antenna array elements can be brought down from 279 to
147 with simultaneous reduction in Side Lobe Level of about
20 dB with a fixed half power beamwidth.
DESIGN AND ANALYSIS OF COMPACT UWB BAND PASS FILTERijeljournal
This paper presents design, implementation and analysis of an ultra-wideband (UWB) band-pass-filter using parallel-coupled microstrip line with defective ground plane and a uniform multi-mode resonator. The structure of the filter is designed on microwave substrate GML 1000 of dielectric constant 3.2 and height is 0.762 mm. Simulation is carried out by CST MSW software and optimized structure is fabricated. The frequency response is measured on vector analyzer and measured results show close approximation with simulation results. In this article modeling of the proposed filter is also reported. The electric model of the filter is analyzed by circuit theory and MATLAB. This model is validated by comparing the results with the CST simulation and VNA measured results. This filter is compact in size of dimension 30˟1.87 mm2 may be useful for modern wireless application of communication.
This document summarizes a presentation about vertical cavity surface emitting lasers (VCSELs). It begins with an introduction to VCSELs and their history. It then discusses VCSEL structure, including distributed Bragg reflectors (DBRs) for optical and current confinement, and rate equations that describe VCSEL characteristics. Continuous wave performance is examined through current-light output curves. Applications include optical fiber data transmission, displays, and sensors. Later sections provide examples of single-mode oxide-confined VCSELs for printers and sensors, electrically pumped GaSb-based VCSELs, and all-optical flip-flop operation using polarization bistable VCSELs.
This document summarizes key concepts about optical amplifiers and networks. It discusses how optical amplifiers work by stimulating emission to amplify light, and describes common amplifier types like semiconductor optical amplifiers, doped fiber amplifiers, and Raman amplifiers. It also provides details on erbium-doped fiber amplifiers, including their operation, architecture, and use in telecommunication networks using SONET/SDH protocols. SONET/SDH networks are often configured in ring topologies to provide protection against link and node failures.
Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigur...IJECEIAES
A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application.
Broadband and efficient full wave rectenna for wireless energy 2019Diana Diana
This document presents a novel approach to designing a broadband full wave rectenna for wireless energy transfer at 2.45 GHz. The rectenna consists of a center shorted dual edge feed microstrip patch antenna and a two diode full wave rectifier. Simulation and experimental results show that the proposed rectenna provides higher RF to DC conversion efficiency than a similar design using a half wave rectifier. A dual feed antenna is used to provide differential voltages at its two feed points, which the full wave rectifier utilizes with its two diodes to convert both half cycles of the incoming AC signal into DC power. The optimized rectenna design is tested and shown to agree with theoretical simulations.
A NEW MODIFIED SYSTEM FOR EQUAL POWER DIVISION WITH LCC FOR WIRELESS APPLCATIONSijistjournal
In this paper, a new modified system for equal power division is implemented with the help of rectangular micro strip patch antenna, Gysel power divider and leakage cancellation circuit. Today’s world power division plays an important role in wireless application areas such as base stations, antenna arrays, handheld devices etc., Here micro strip patch antenna is implemented with FR4 as a substrate material due to its benefits such as low loss and low fabrication cost while the ground material is aluminium due to its conductivity. For a good system, the return loss should be highly desirable and insertion loss should be low. Our proposed system is designed with a combination of micro strip patch antenna, leakage cancellation circuit and Gysel power divider produces equal power division with low loss such as insertion loss is measured as -39.291dB, return loss as -16.11dB and leakage cancellation as 6dB which was designed and simulated in Agilent Advanced Design System software (2009).
This document describes the design and simulation of a dual-fed circularly polarized microstrip patch antenna for WLAN applications at 2.4 GHz. A circular patch antenna with a diameter of 30 mm is designed on an FR4 substrate with a dielectric constant of 4.6 and thickness of 1.6 mm. Circular polarization is achieved by feeding the patch from two points with a 90 degree phase difference using a 3dB hybrid coupler. The antenna is simulated using ADS software. Simulation results show the antenna resonates at 2.404 GHz with a return loss of -28.003 dB and gain of 6.368 dB. The antenna provides circular polarization as required for WLAN applications.
An antenna is a specialized transducer that converts radio-frequency (RF) fields into alternating current (AC) or vice-versa. ... At frequencies below 3 GHz, many different types of antennas are used. The simplest is a length of wire, connected at one end to a transmitter or receiver
Notes on optical fiber communication unit7Jagadish M
This document summarizes key concepts in wavelength division multiplexing (WDM). It discusses how WDM allows multiple independent wavelengths to be transmitted simultaneously over the same optical fiber, dramatically increasing fiber capacity. It describes the passive and active components used to combine, distribute, isolate, and amplify different wavelengths. These include multiplexers, demultiplexers, optical isolators, thin film filters, and various types of optical amplifiers. WDM standards set by the ITU are also summarized, which specify wavelength grids and channel spacings.
This document summarizes the evolution of low-cost construction using surplus satellite TV LNBs (low noise block downconverters). It begins with an introduction to the author's history with analog satellite TV and fascination with stripping down LNBs. It then provides a detailed overview of the technology and design of early single-output Ku-band LNBs from the 1990s, followed by early dual-output and current single-output extended band LNB designs. The document concludes by listing 10 potential reuses for spare or unwanted LNBs, such as using their GaAsFETs and MMICs for microwave circuits, or converting them for use as antennas, amplifiers, or frequency converters.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Integrated sub-harmonically pumped up-converter antenna for spatial power com...fanfan he
This document describes the design and measurement of an integrated sub-harmonically pumped up-converter antenna array for spatial power combining. Key points:
1) A Ka-band up-converter using a substrate integrated waveguide bandpass filter is designed with a conversion loss of around 7 dB.
2) An integrated up-converter antenna element is designed by combining the up-converter with a substrate integrated waveguide fed antipodal linearly tapered slot antenna.
3) A 2x2 array of the integrated up-converter antennas is fabricated and measured to have a power combining efficiency above 90% and third order intercept point EIRP of 16 dBm, showing its potential as a low-cost transmitter.
This document describes the design and simulation of an ultra-wideband balanced bandpass filter. Key points:
1) The filter uses defected ground structures (DGS) to provide common mode rejection. It has three sections - a pair of UWB filtering units for the differential lines, U-shaped and H-shaped DGSs for lower band suppression, and dumbbell-shaped DGSs for upper band suppression.
2) An equivalent lumped element model is developed and parameters are extracted to represent the common mode response of each section.
3) Simulation results show the filter provides good differential mode propagation and common mode suppression from DC to 18GHz, meeting the requirements for modern communication systems
This document discusses patch antennas. It describes the basic structure of a patch antenna, which consists of a radiating metallic patch on a dielectric substrate with a ground plane on the other side. Patch antennas radiate a linearly polarized wave and have a very low profile. Their primary limitation is narrow bandwidth, which is typically less than 5% for single-substrate designs. Common patch antenna geometries include rectangular and circular shapes to generate different beam patterns.
This document summarizes a seminar presentation on distributed amplifiers. It begins with an introduction describing how distributed amplifiers were first introduced to overcome bandwidth limitations of vacuum tube amplifiers by using parasitic capacitances and inductors to form transmission lines. It then provides the basic design circuit of a distributed amplifier consisting of input and output transmission lines coupled by transistors. Next, it explains the operating principle where signals traveling on the gate and drain lines add in the forward direction. It also includes analysis of the gate and drain line transmission models and how to calculate the optimum number of stages to cascade for maximum power gain before the input signal decays exponentially.
1. A light emitting diode (LED) is a p-n junction diode that emits light when forward biased as electrons and holes recombine and release energy as photons.
2. The energy conversion in an LED occurs in two stages: carriers in the semiconductor absorb electrical energy raising them above equilibrium value, and most carriers give up this energy as spontaneous photon emission when they recombine.
3. The wavelength of light emitted by an LED depends on the bandgap of the semiconductor material, with lower bandgap materials emitting infrared light and higher bandgap materials emitting visible light.
The LNB (low noise block) is a key component of a satellite dish that collects and processes weak satellite signals. It contains electronic components that convert the signals to a lower frequency and amplify them for transmission to receivers via coaxial cable. LNBs are designed for specific frequency bands and polarizations. A universal LNB can receive both horizontal and vertical polarizations in the Ku band through voltage switching. Different LNB types support varying numbers of receivers and satellites through features like DiSEqC switching and multifeed designs.
This document describes the design of a planar quasi-Yagi antenna capable of achieving high gain, wide bandwidth, and high front-to-back ratio. The antenna consists of a driven dipole element, reflector ground plane, and 5 director elements printed on a substrate. Optimization of the distances between the elements results in bandwidths over 600 MHz with gains above 6 dBi and front-to-back ratios greater than 34 dB. Measurements show good agreement with simulations, demonstrating this antenna design is suitable for applications requiring highly directive radiation patterns.
The document discusses erbium-doped fiber lasers (EDFLs). EDFLs emit light at 1.55μm, which lies in the eye-safe region of the spectrum and is preferred for long-distance fiber optic communications. They consist of an optical fiber doped with erbium ions as the gain medium, pump lasers to excite the erbium ions, and dielectric mirrors or fiber Bragg gratings to form the optical resonator. EDFLs have revolutionized fiber optic communications and next generation versions may be integrated onto single chips.
Wideband circularly polarized cavity backed aperture antenna with a parasitic...Mohit Joshi
This document summarizes a wideband circularly polarized cavity-backed aperture antenna. The proposed antenna consists of a circular aperture antenna, a low-profile backed cavity, and a parasitic square patch. The cavity provides unidirectional radiation while the parasitic patch enhances the axial ratio bandwidth. Measured results show the antenna achieves over 70% impedance bandwidth and 43.3% 3dB axial ratio bandwidth with a peak gain of 8.6 dBi. The antenna operates at 6 GHz with compact size and combines wide bandwidths, high efficiency, and ease of design and integration.
Chapter7 - Small-signal RF Amplifier TheoriesFabian Kung
Provides an overview high-frequency amplifier behaviors under small-signal or linear condition. Focuses on checking the stability of the amplifier and computing the power gains.
The frequency response of RC high pass circuits is summarized. As frequency decreases below the cutoff frequency f1, the capacitor's reactance increases, reducing the output voltage. The cutoff frequency f1 is calculated as 1/(2πRC). Gain is 0 dB at f1 and drops at -20dB/decade below f1. Circuit analysis equations show output voltage decreases proportional to frequency below f1. The circuit thus passes high frequencies above f1 but blocks lower frequencies.
This document discusses mobile communication and propagation challenges, including short antenna heights and time-varying propagation paths. It then introduces OFDM as a modulation technique that uses channel coding and multiple narrowband subcarriers to solve multipath problems. OFDM allows parallel transmission of data across multiple frequencies to mitigate frequency-selective fading on mobile channels. The document also covers spread spectrum techniques like frequency hopping and direct sequence spread spectrum that make wireless signals resistant to interference and interception by spreading them across a wider frequency band.
This document describes properties of the radio path in GSM including fast fading caused by multipath propagation which results in problems like inter-symbol interference. It discusses solutions like frequency hopping, channel coding, and antenna diversity. It also describes logical channels in the air interface like traffic channels and control channels, and different burst types like synchronization bursts, normal bursts and access bursts used to transmit different logical channels.
This document summarizes key concepts about optical amplifiers and networks. It discusses how optical amplifiers work by stimulating emission to amplify light, and describes common amplifier types like semiconductor optical amplifiers, doped fiber amplifiers, and Raman amplifiers. It also provides details on erbium-doped fiber amplifiers, including their operation, architecture, and use in telecommunication networks using SONET/SDH protocols. SONET/SDH networks are often configured in ring topologies to provide protection against link and node failures.
Dual Band to Wideband Pentagon-shaped Patch Antenna with Frequency Reconfigur...IJECEIAES
A dual band to wideband reconfigurable pentagon-shaped antenna with EBG unit cell is proposed. A minimal number of two EBG unit cell is deployed to realize frequency reconfigurable mechanism. By varying the state of the EBG the antenna is capable to change its dual band operation to wideband alternately. There are three cases that have been analysed, first case is the EBG incorporated antenna with ideal and second is with the active EBG. Subsequently, the third cases is the fabricated ideal EBG incorporated antenna. The dual band operation is at 1.8 GHz and 5.2 GHz while the wide band from 1.6 GHz to 2.37 GHz (770 MHz). The proposed reconfigurable antenna is suitable to be implemented for LTE (1.6 GHz), Wi-Fi (5.2 GHz), WiMAX (2.3 GHz) and cognitive radio application.
Broadband and efficient full wave rectenna for wireless energy 2019Diana Diana
This document presents a novel approach to designing a broadband full wave rectenna for wireless energy transfer at 2.45 GHz. The rectenna consists of a center shorted dual edge feed microstrip patch antenna and a two diode full wave rectifier. Simulation and experimental results show that the proposed rectenna provides higher RF to DC conversion efficiency than a similar design using a half wave rectifier. A dual feed antenna is used to provide differential voltages at its two feed points, which the full wave rectifier utilizes with its two diodes to convert both half cycles of the incoming AC signal into DC power. The optimized rectenna design is tested and shown to agree with theoretical simulations.
A NEW MODIFIED SYSTEM FOR EQUAL POWER DIVISION WITH LCC FOR WIRELESS APPLCATIONSijistjournal
In this paper, a new modified system for equal power division is implemented with the help of rectangular micro strip patch antenna, Gysel power divider and leakage cancellation circuit. Today’s world power division plays an important role in wireless application areas such as base stations, antenna arrays, handheld devices etc., Here micro strip patch antenna is implemented with FR4 as a substrate material due to its benefits such as low loss and low fabrication cost while the ground material is aluminium due to its conductivity. For a good system, the return loss should be highly desirable and insertion loss should be low. Our proposed system is designed with a combination of micro strip patch antenna, leakage cancellation circuit and Gysel power divider produces equal power division with low loss such as insertion loss is measured as -39.291dB, return loss as -16.11dB and leakage cancellation as 6dB which was designed and simulated in Agilent Advanced Design System software (2009).
This document describes the design and simulation of a dual-fed circularly polarized microstrip patch antenna for WLAN applications at 2.4 GHz. A circular patch antenna with a diameter of 30 mm is designed on an FR4 substrate with a dielectric constant of 4.6 and thickness of 1.6 mm. Circular polarization is achieved by feeding the patch from two points with a 90 degree phase difference using a 3dB hybrid coupler. The antenna is simulated using ADS software. Simulation results show the antenna resonates at 2.404 GHz with a return loss of -28.003 dB and gain of 6.368 dB. The antenna provides circular polarization as required for WLAN applications.
An antenna is a specialized transducer that converts radio-frequency (RF) fields into alternating current (AC) or vice-versa. ... At frequencies below 3 GHz, many different types of antennas are used. The simplest is a length of wire, connected at one end to a transmitter or receiver
Notes on optical fiber communication unit7Jagadish M
This document summarizes key concepts in wavelength division multiplexing (WDM). It discusses how WDM allows multiple independent wavelengths to be transmitted simultaneously over the same optical fiber, dramatically increasing fiber capacity. It describes the passive and active components used to combine, distribute, isolate, and amplify different wavelengths. These include multiplexers, demultiplexers, optical isolators, thin film filters, and various types of optical amplifiers. WDM standards set by the ITU are also summarized, which specify wavelength grids and channel spacings.
This document summarizes the evolution of low-cost construction using surplus satellite TV LNBs (low noise block downconverters). It begins with an introduction to the author's history with analog satellite TV and fascination with stripping down LNBs. It then provides a detailed overview of the technology and design of early single-output Ku-band LNBs from the 1990s, followed by early dual-output and current single-output extended band LNB designs. The document concludes by listing 10 potential reuses for spare or unwanted LNBs, such as using their GaAsFETs and MMICs for microwave circuits, or converting them for use as antennas, amplifiers, or frequency converters.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Integrated sub-harmonically pumped up-converter antenna for spatial power com...fanfan he
This document describes the design and measurement of an integrated sub-harmonically pumped up-converter antenna array for spatial power combining. Key points:
1) A Ka-band up-converter using a substrate integrated waveguide bandpass filter is designed with a conversion loss of around 7 dB.
2) An integrated up-converter antenna element is designed by combining the up-converter with a substrate integrated waveguide fed antipodal linearly tapered slot antenna.
3) A 2x2 array of the integrated up-converter antennas is fabricated and measured to have a power combining efficiency above 90% and third order intercept point EIRP of 16 dBm, showing its potential as a low-cost transmitter.
This document describes the design and simulation of an ultra-wideband balanced bandpass filter. Key points:
1) The filter uses defected ground structures (DGS) to provide common mode rejection. It has three sections - a pair of UWB filtering units for the differential lines, U-shaped and H-shaped DGSs for lower band suppression, and dumbbell-shaped DGSs for upper band suppression.
2) An equivalent lumped element model is developed and parameters are extracted to represent the common mode response of each section.
3) Simulation results show the filter provides good differential mode propagation and common mode suppression from DC to 18GHz, meeting the requirements for modern communication systems
This document discusses patch antennas. It describes the basic structure of a patch antenna, which consists of a radiating metallic patch on a dielectric substrate with a ground plane on the other side. Patch antennas radiate a linearly polarized wave and have a very low profile. Their primary limitation is narrow bandwidth, which is typically less than 5% for single-substrate designs. Common patch antenna geometries include rectangular and circular shapes to generate different beam patterns.
This document summarizes a seminar presentation on distributed amplifiers. It begins with an introduction describing how distributed amplifiers were first introduced to overcome bandwidth limitations of vacuum tube amplifiers by using parasitic capacitances and inductors to form transmission lines. It then provides the basic design circuit of a distributed amplifier consisting of input and output transmission lines coupled by transistors. Next, it explains the operating principle where signals traveling on the gate and drain lines add in the forward direction. It also includes analysis of the gate and drain line transmission models and how to calculate the optimum number of stages to cascade for maximum power gain before the input signal decays exponentially.
1. A light emitting diode (LED) is a p-n junction diode that emits light when forward biased as electrons and holes recombine and release energy as photons.
2. The energy conversion in an LED occurs in two stages: carriers in the semiconductor absorb electrical energy raising them above equilibrium value, and most carriers give up this energy as spontaneous photon emission when they recombine.
3. The wavelength of light emitted by an LED depends on the bandgap of the semiconductor material, with lower bandgap materials emitting infrared light and higher bandgap materials emitting visible light.
The LNB (low noise block) is a key component of a satellite dish that collects and processes weak satellite signals. It contains electronic components that convert the signals to a lower frequency and amplify them for transmission to receivers via coaxial cable. LNBs are designed for specific frequency bands and polarizations. A universal LNB can receive both horizontal and vertical polarizations in the Ku band through voltage switching. Different LNB types support varying numbers of receivers and satellites through features like DiSEqC switching and multifeed designs.
This document describes the design of a planar quasi-Yagi antenna capable of achieving high gain, wide bandwidth, and high front-to-back ratio. The antenna consists of a driven dipole element, reflector ground plane, and 5 director elements printed on a substrate. Optimization of the distances between the elements results in bandwidths over 600 MHz with gains above 6 dBi and front-to-back ratios greater than 34 dB. Measurements show good agreement with simulations, demonstrating this antenna design is suitable for applications requiring highly directive radiation patterns.
The document discusses erbium-doped fiber lasers (EDFLs). EDFLs emit light at 1.55μm, which lies in the eye-safe region of the spectrum and is preferred for long-distance fiber optic communications. They consist of an optical fiber doped with erbium ions as the gain medium, pump lasers to excite the erbium ions, and dielectric mirrors or fiber Bragg gratings to form the optical resonator. EDFLs have revolutionized fiber optic communications and next generation versions may be integrated onto single chips.
Wideband circularly polarized cavity backed aperture antenna with a parasitic...Mohit Joshi
This document summarizes a wideband circularly polarized cavity-backed aperture antenna. The proposed antenna consists of a circular aperture antenna, a low-profile backed cavity, and a parasitic square patch. The cavity provides unidirectional radiation while the parasitic patch enhances the axial ratio bandwidth. Measured results show the antenna achieves over 70% impedance bandwidth and 43.3% 3dB axial ratio bandwidth with a peak gain of 8.6 dBi. The antenna operates at 6 GHz with compact size and combines wide bandwidths, high efficiency, and ease of design and integration.
Chapter7 - Small-signal RF Amplifier TheoriesFabian Kung
Provides an overview high-frequency amplifier behaviors under small-signal or linear condition. Focuses on checking the stability of the amplifier and computing the power gains.
The frequency response of RC high pass circuits is summarized. As frequency decreases below the cutoff frequency f1, the capacitor's reactance increases, reducing the output voltage. The cutoff frequency f1 is calculated as 1/(2πRC). Gain is 0 dB at f1 and drops at -20dB/decade below f1. Circuit analysis equations show output voltage decreases proportional to frequency below f1. The circuit thus passes high frequencies above f1 but blocks lower frequencies.
This document discusses mobile communication and propagation challenges, including short antenna heights and time-varying propagation paths. It then introduces OFDM as a modulation technique that uses channel coding and multiple narrowband subcarriers to solve multipath problems. OFDM allows parallel transmission of data across multiple frequencies to mitigate frequency-selective fading on mobile channels. The document also covers spread spectrum techniques like frequency hopping and direct sequence spread spectrum that make wireless signals resistant to interference and interception by spreading them across a wider frequency band.
This document describes properties of the radio path in GSM including fast fading caused by multipath propagation which results in problems like inter-symbol interference. It discusses solutions like frequency hopping, channel coding, and antenna diversity. It also describes logical channels in the air interface like traffic channels and control channels, and different burst types like synchronization bursts, normal bursts and access bursts used to transmit different logical channels.
There are many types of wireless channel impairments such as noise, path loss, shadowing, and fading and impairment Mitigation techniques should be adopted according to system requirements and channel environments.
This document proposes and evaluates a new radio access technology (RAT) selection algorithm called Network Controlled Cell Breathing (NCCB) for heterogeneous CDMA/TDMA networks handling multiple services. NCCB aims to increase capacity by controlling the effective cell radius of the CDMA network to reduce interference. Several RAT selection strategies are presented that combine NCCB with service-based policies. System-level simulations of voice and interactive traffic show NCCB can achieve significant throughput gains over traditional load balancing approaches by better managing interference patterns.
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.
Diversity Techniques in Wireless CommunicationSahar Foroughi
This document discusses diversity techniques for wireless communication, including cooperative diversity. It begins by introducing wireless systems and the impairments they face like fading. It then covers various diversity techniques like space, frequency, and time diversity that provide multiple transmission paths to reduce fading. Cooperative diversity is described as allowing single-antenna devices to achieve MIMO-like benefits by sharing antennas. The document outlines cooperative transmission protocols and challenges at different network layers in implementing cooperation. In conclusion, diversity techniques improve performance by providing multiple signal replicas to overcome fading, while cooperation enables reliability and throughput gains with challenges to address across protocol layers.
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.
CDMA is a digital cellular standard that allows multiple users to access the same radio frequency channel simultaneously through the use of unique code sequences. Users are separated by spreading their transmitted signals across the frequency band using pseudo-random codes. CDMA provides advantages over other multiple access techniques like FDMA and TDMA such as increased capacity, soft handoffs between cells, and covert operation due to its noise-like signals. The IS-95 standard introduced CDMA to cellular networks and specified the use of orthogonal codes to separate signals and a 1.25 MHz channel bandwidth to support multiple simultaneous voice calls.
CDMA is a digital cellular technology that allows multiple users to access a single radio channel simultaneously through the use of unique code assignments. The document discusses CDMA network architecture, which includes mobile stations, base stations, base station controllers, mobile switching centers, home and visitor location registers, and authentication centers. It also compares CDMA to earlier multiple access technologies like TDMA and FDMA, noting advantages of CDMA like increased capacity and soft handoffs between cells using the same frequency.
Physical channels carry information over the air interface between the mobile station and base transceiver station. Logical channels map user data and signaling information onto physical channels. There are two main types of logical channels - traffic channels which carry call data, and control channels which communicate service information. Control channels include broadcast channels which transmit cell-wide information, common channels used for paging and access procedures, and dedicated channels for signaling during calls or when not on a call. Logical channels are mapped onto physical channels to effectively transmit information wirelessly between network components in a GSM system.
This document discusses image compression techniques. It begins by defining image compression as reducing the data required to represent a digital image. It then discusses why image compression is needed for storage, transmission and other applications. The document outlines different types of redundancies that can be exploited in compression, including spatial, temporal and psychovisual redundancies. It categorizes compression techniques as lossless or lossy and describes several algorithms for each type, including Huffman coding, LZW coding, DPCM, DCT and others. Key aspects like prediction, quantization, fidelity criteria and compression models are also summarized.
GSM uses frequency division duplexing with carriers separated by 200 kHz. Each carrier is divided into 8 time slots using TDMA. Logical channels like traffic channels and signaling channels are mapped onto these physical time slots. Traffic channels carry user data at either full rate or half rate, while signaling channels include broadcast, common, and dedicated control channels used for functions like synchronization, paging, call setup, and handover.
TECHNIQUES TO COMBAT OSNR IN DWDM LINKSMapYourTech
This document discusses optical signal-to-noise ratio (OSNR) in dense wavelength division multiplexing (DWDM) systems. It explains that OSNR is an important parameter that determines transmission distance and quality. Lower OSNR means higher bit error rates at the receiver. The document lists several factors that affect OSNR requirements, such as location in the network, data rate, target bit error rate, and network type. It also summarizes various techniques to improve OSNR, including using optical amplifiers, advanced fiber designs, hybrid amplifier configurations, macro bending of fibers, and multi-level modulation formats.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The document describes the electrical properties and modeling of nerve cell membranes. Key points:
1) The lipid bilayer acts as a capacitor, separating charges across the membrane. Ion channels act as conductive pathways. Ion gradients establish "batteries" that drive ion flows.
2) Hodgkin and Huxley modeled the membrane as an electrical circuit with a battery (resting potential) in series with a conductance (ion channels). This basic model represents the properties of a small membrane patch.
3) The Nernst equation relates the equilibrium potential for a specific ion to its concentration gradient. The Goldman equation generalizes this for multiple permeant ions. At equilibrium, the membrane potential balances
This document provides a seminar report on Cellonics technology, which allows for modem speeds 1,000 times faster than current technologies. It discusses the principles of Cellonics, which are inspired by how biological cells communicate through nonlinear dynamical systems. Cellonics circuits mimic this behavior to encode and transmit digital data. Applications to telecommunications are explored, demonstrating carrier-rate decoding that transmits one symbol per radio frequency cycle, vastly increasing data rates. Proof-of-concept systems are presented, including wired and wireless narrowband communication systems transmitting at 5.7 Mbps and 26.7 Mbps respectively, showcasing the speed and robustness of Cellonics technology.
This document provides an overview of wireless communications and networks. It discusses key concepts in cellular networks including what a cell is, frequency reuse, channel assignment strategies, and the handoff process. Cells are defined as the coverage area of a base station. Regular hexagonal geometry is used for cell structure. Frequency reuse allows the same frequencies to be used in different cells through a clustering approach to improve capacity. Channel assignment can be fixed or dynamic. The handoff process allows calls to be transferred between base stations as users move through different cells. Later generations of cellular networks have reduced the handoff delay.
This document provides an overview of wireless communications and networks. It discusses key concepts in cellular networks including what a cell is, frequency reuse, channel assignment strategies, and the handoff process. Cells are defined as the coverage area of a base station. Regular hexagonal geometry is used for cell structure. Frequency reuse allows the same frequencies to be used in different cells through a clustering pattern to improve capacity. Channel assignment can be fixed or dynamic. The handoff process allows calls to be transferred between base stations as users move through different cells without interrupting calls. Later generations of cellular networks have reduced handoff delays.
This document discusses smart co-channel interference mitigation techniques in MIMO communication networks. It examines the problem of interference when there are many transmitter-receiver pairs operating in a small area using MIMO. Simply increasing transmit power is not optimal, and capacity per unit area is a better metric. The document analyzes the channel capacity for an uninformed transmitter with no channel state information and an informed transmitter with feedback. It finds that an informed transmitter using techniques like water-filling of transmit power across antenna modes can improve resistance to interference. Further improvements may come from combining methods such as power control, channel sensing, link adaptation, and transmit/receive beamforming to significantly increase network capacity density.
This paper analyses the concept of wireless power transmission for mobile charging via three major methodologies of radioactive wave; coupled magnetic resonance; and induction resonance both electromagnetic and NFC-enabled. It describes each methods in viewpoints of their contrast, strengths, shortcomings and impact on society. It concludes that a RF-DC method be explored for improvement.
An Intercell Interference Coordination Scheme in LTE Downlink Networks based ...ijwmn
The document proposes an intercell interference coordination scheme for LTE downlink networks based on user priority and fuzzy logic. It calculates user priority based on interference level, QoS, and delay. Users are then scheduled on subbands according to their priority. ENodeBs dynamically control transmit power using fuzzy logic and message exchanges to reduce interference between cells. Simulation results show the proposed scheme outperforms existing reuse factor one and soft frequency reuse schemes in terms of cell throughput, cell edge throughput, delay, and interference level.
This document discusses the concept of cellular communications and frequency reuse. It describes how early mobile phone systems used high-powered transmitters with large coverage areas and low capacity. Cellular systems divide the coverage area into smaller cells served by low-power transmitters to reuse frequencies and increase capacity. Cells are arranged in a hexagonal layout and frequencies are reused in clusters of cells separated by a reuse distance to avoid interference. The cluster size determines the system's capacity and interference levels.
1. The document discusses facilitated diffusion, which is the transport of substances across a membrane with the aid of carrier proteins. It involves substances moving uphill against a concentration gradient, with the carrier protein having a fixed affinity for the substance and ATP being used to flip the orientation or change the affinity of the binding site.
2. It then covers the resting membrane potential, how cells create charge separation across the membrane by establishing ion concentration gradients and allowing diffusion through leak channels, and how this results in a membrane potential. Key ions involved are sodium, potassium, and macromolecular anions.
3. It defines graded potentials as local changes in membrane potential caused by transient opening of non-voltage gated ion channels that
Osc mac duty cycle with multi helpers ct mode wi-lem technology in wireless s...ijwmn
Recently, Wireless Sensor Networks (WSNs) grow to be one of the dominant technology trends; new needs
are continuously emerging and demanding more complex constraints in a duty cycle, such as extend the life
time communication . The MAC layer plays a crucial role in these networks; it controls the communication
module and manages the medium sharing. In this work we use OSC-MAC tackles combining with the
performance of cooperative transmission (CT) in multi-hop WSN and the Wi-Lem technology
The cellular concept was developed to solve the problem of spectral congestion and increase user capacity without major technological changes. It involves replacing single, high power transmitters with many low power transmitters covering small areas. Neighboring cells are assigned different channel groups to minimize interference, and the same channels are reused at different locations. When designing cellular systems, providing good coverage and services in high density areas requires considering factors like geographical separation and shadowing effects that allow frequency reuse.
Adjacent Channel Interference In IEEE 802.11 NAsia Smith
This document analyzes the effects of adjacent channel interference (ACI) on the IEEE 802.11n wireless networking standard. It finds that ACI can cause both a variant of the exposed terminal problem, where carrier sensing prevents concurrent transmissions, as well as a variant of the hidden terminal problem, where ACI causes packet collisions. Experimental results show that the number of available orthogonal channels depends on factors like the spatial separation between radios, channel width, frequency band, and traffic patterns. In multi-radio systems with little separation between antennas, ACI significantly reduces the number of usable channels.
Multidisciplinary Journal Supported by TETFund. The journals would publish papers covering a wide range of subjects in journal science, management science, educational, agricultural, architectural, accounting and finance, business administration, entrepreneurship, business education, all journals
A folded floating-gate CMOS biosensor is realized for the detection of charged biochemical molecules. The biosensor comprises a field-effect transistor with a floating-gate, a control-gate, and a sensing area. Charged biochemical molecules placed on the sensing area induce a voltage on the floating-gate and a relative shift in the threshold characteristics. Compared to conventional devices, the floating-gate here is folded to span the entire device. This allows us to place the sensing area above the field-effect transistor (FET), thus reducing the total device area. The fabricated devices show good sensitivity to the polarity and concentration of charged poly amino acids. Possible applications of the device include electronic detection of spatial and temporal charge migration such as in biological processes.
This document provides an overview of wireless communication and cellular systems. It discusses key concepts such as frequency reuse, cell footprint, handover, interference, and system capacity. It explains how cellular networks divide a service area into smaller cells served by low-power base stations to improve capacity. Neighboring cells are assigned different frequency groups to reduce interference. The same frequencies can be reused in cells far enough apart. Handover allows calls to be transferred between cells as users move. The document also covers channel assignment strategies and methods for expanding system capacity through cell splitting or reducing the frequency reuse factor.
Interference management in lte downlink networksijwmn
Two major challenges for evolving LTE (Long Term Evolution) networks are to achieve enhanced system capacity and cell coverage compared with WCDMA (Wideband Code Division Multiple Access) system. Effective utilization of radio resources as well as dense spectrum reuse are at the core to attain these targets. However, dense frequency reuse may increase inter-cell interference, which in turn severely limits the capacity of users in the system. Inter-cell interference can restrict overall system performance in terms of throughput and spectral efficiency, especially for the users located at the cell edge area. Hence, careful management of inter-cell interferences becomes crucial to improve LTE system performance. In this paper, interference mitigation schemes for LTE downlink networks are investigated.
Chapter 09.ppt Physical elements of Transistorscbcbgdfgsdf
This document summarizes key concepts about bipolar transistors from Chapter Nine of the textbook "Physical Electronics Of Transistors". It discusses bipolar transistors as active devices that can control electrical energy flow. The chapter covers the physical basis of transistor operation including injection, diffusion and collection processes. It also describes transistor circuit symbols, regions of operation, input/output characteristics, and maximum voltage and current limits. Bipolar transistors consist of an NPN or PNP semiconductor structure and operate by controlling minority carrier flow between the emitter, base and collector terminals.
Sudheer Mechineni, Head of Application Frameworks, Standard Chartered Bank
Discover how Standard Chartered Bank harnessed the power of Neo4j to transform complex data access challenges into a dynamic, scalable graph database solution. This keynote will cover their journey from initial adoption to deploying a fully automated, enterprise-grade causal cluster, highlighting key strategies for modelling organisational changes and ensuring robust disaster recovery. Learn how these innovations have not only enhanced Standard Chartered Bank’s data infrastructure but also positioned them as pioneers in the banking sector’s adoption of graph technology.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/06/building-and-scaling-ai-applications-with-the-nx-ai-manager-a-presentation-from-network-optix/
Robin van Emden, Senior Director of Data Science at Network Optix, presents the “Building and Scaling AI Applications with the Nx AI Manager,” tutorial at the May 2024 Embedded Vision Summit.
In this presentation, van Emden covers the basics of scaling edge AI solutions using the Nx tool kit. He emphasizes the process of developing AI models and deploying them globally. He also showcases the conversion of AI models and the creation of effective edge AI pipelines, with a focus on pre-processing, model conversion, selecting the appropriate inference engine for the target hardware and post-processing.
van Emden shows how Nx can simplify the developer’s life and facilitate a rapid transition from concept to production-ready applications.He provides valuable insights into developing scalable and efficient edge AI solutions, with a strong focus on practical implementation.
In the rapidly evolving landscape of technologies, XML continues to play a vital role in structuring, storing, and transporting data across diverse systems. The recent advancements in artificial intelligence (AI) present new methodologies for enhancing XML development workflows, introducing efficiency, automation, and intelligent capabilities. This presentation will outline the scope and perspective of utilizing AI in XML development. The potential benefits and the possible pitfalls will be highlighted, providing a balanced view of the subject.
We will explore the capabilities of AI in understanding XML markup languages and autonomously creating structured XML content. Additionally, we will examine the capacity of AI to enrich plain text with appropriate XML markup. Practical examples and methodological guidelines will be provided to elucidate how AI can be effectively prompted to interpret and generate accurate XML markup.
Further emphasis will be placed on the role of AI in developing XSLT, or schemas such as XSD and Schematron. We will address the techniques and strategies adopted to create prompts for generating code, explaining code, or refactoring the code, and the results achieved.
The discussion will extend to how AI can be used to transform XML content. In particular, the focus will be on the use of AI XPath extension functions in XSLT, Schematron, Schematron Quick Fixes, or for XML content refactoring.
The presentation aims to deliver a comprehensive overview of AI usage in XML development, providing attendees with the necessary knowledge to make informed decisions. Whether you’re at the early stages of adopting AI or considering integrating it in advanced XML development, this presentation will cover all levels of expertise.
By highlighting the potential advantages and challenges of integrating AI with XML development tools and languages, the presentation seeks to inspire thoughtful conversation around the future of XML development. We’ll not only delve into the technical aspects of AI-powered XML development but also discuss practical implications and possible future directions.
Infrastructure Challenges in Scaling RAG with Custom AI modelsZilliz
Building Retrieval-Augmented Generation (RAG) systems with open-source and custom AI models is a complex task. This talk explores the challenges in productionizing RAG systems, including retrieval performance, response synthesis, and evaluation. We’ll discuss how to leverage open-source models like text embeddings, language models, and custom fine-tuned models to enhance RAG performance. Additionally, we’ll cover how BentoML can help orchestrate and scale these AI components efficiently, ensuring seamless deployment and management of RAG systems in the cloud.
Climate Impact of Software Testing at Nordic Testing DaysKari Kakkonen
My slides at Nordic Testing Days 6.6.2024
Climate impact / sustainability of software testing discussed on the talk. ICT and testing must carry their part of global responsibility to help with the climat warming. We can minimize the carbon footprint but we can also have a carbon handprint, a positive impact on the climate. Quality characteristics can be added with sustainability, and then measured continuously. Test environments can be used less, and in smaller scale and on demand. Test techniques can be used in optimizing or minimizing number of tests. Test automation can be used to speed up testing.
Why You Should Replace Windows 11 with Nitrux Linux 3.5.0 for enhanced perfor...SOFTTECHHUB
The choice of an operating system plays a pivotal role in shaping our computing experience. For decades, Microsoft's Windows has dominated the market, offering a familiar and widely adopted platform for personal and professional use. However, as technological advancements continue to push the boundaries of innovation, alternative operating systems have emerged, challenging the status quo and offering users a fresh perspective on computing.
One such alternative that has garnered significant attention and acclaim is Nitrux Linux 3.5.0, a sleek, powerful, and user-friendly Linux distribution that promises to redefine the way we interact with our devices. With its focus on performance, security, and customization, Nitrux Linux presents a compelling case for those seeking to break free from the constraints of proprietary software and embrace the freedom and flexibility of open-source computing.
GraphSummit Singapore | The Future of Agility: Supercharging Digital Transfor...Neo4j
Leonard Jayamohan, Partner & Generative AI Lead, Deloitte
This keynote will reveal how Deloitte leverages Neo4j’s graph power for groundbreaking digital twin solutions, achieving a staggering 100x performance boost. Discover the essential role knowledge graphs play in successful generative AI implementations. Plus, get an exclusive look at an innovative Neo4j + Generative AI solution Deloitte is developing in-house.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
TrustArc Webinar - 2024 Global Privacy SurveyTrustArc
How does your privacy program stack up against your peers? What challenges are privacy teams tackling and prioritizing in 2024?
In the fifth annual Global Privacy Benchmarks Survey, we asked over 1,800 global privacy professionals and business executives to share their perspectives on the current state of privacy inside and outside of their organizations. This year’s report focused on emerging areas of importance for privacy and compliance professionals, including considerations and implications of Artificial Intelligence (AI) technologies, building brand trust, and different approaches for achieving higher privacy competence scores.
See how organizational priorities and strategic approaches to data security and privacy are evolving around the globe.
This webinar will review:
- The top 10 privacy insights from the fifth annual Global Privacy Benchmarks Survey
- The top challenges for privacy leaders, practitioners, and organizations in 2024
- Key themes to consider in developing and maintaining your privacy program
UiPath Test Automation using UiPath Test Suite series, part 6DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 6. In this session, we will cover Test Automation with generative AI and Open AI.
UiPath Test Automation with generative AI and Open AI webinar offers an in-depth exploration of leveraging cutting-edge technologies for test automation within the UiPath platform. Attendees will delve into the integration of generative AI, a test automation solution, with Open AI advanced natural language processing capabilities.
Throughout the session, participants will discover how this synergy empowers testers to automate repetitive tasks, enhance testing accuracy, and expedite the software testing life cycle. Topics covered include the seamless integration process, practical use cases, and the benefits of harnessing AI-driven automation for UiPath testing initiatives. By attending this webinar, testers, and automation professionals can gain valuable insights into harnessing the power of AI to optimize their test automation workflows within the UiPath ecosystem, ultimately driving efficiency and quality in software development processes.
What will you get from this session?
1. Insights into integrating generative AI.
2. Understanding how this integration enhances test automation within the UiPath platform
3. Practical demonstrations
4. Exploration of real-world use cases illustrating the benefits of AI-driven test automation for UiPath
Topics covered:
What is generative AI
Test Automation with generative AI and Open AI.
UiPath integration with generative AI
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Cosa hanno in comune un mattoncino Lego e la backdoor XZ?Speck&Tech
ABSTRACT: A prima vista, un mattoncino Lego e la backdoor XZ potrebbero avere in comune il fatto di essere entrambi blocchi di costruzione, o dipendenze di progetti creativi e software. La realtà è che un mattoncino Lego e il caso della backdoor XZ hanno molto di più di tutto ciò in comune.
Partecipate alla presentazione per immergervi in una storia di interoperabilità, standard e formati aperti, per poi discutere del ruolo importante che i contributori hanno in una comunità open source sostenibile.
BIO: Sostenitrice del software libero e dei formati standard e aperti. È stata un membro attivo dei progetti Fedora e openSUSE e ha co-fondato l'Associazione LibreItalia dove è stata coinvolta in diversi eventi, migrazioni e formazione relativi a LibreOffice. In precedenza ha lavorato a migrazioni e corsi di formazione su LibreOffice per diverse amministrazioni pubbliche e privati. Da gennaio 2020 lavora in SUSE come Software Release Engineer per Uyuni e SUSE Manager e quando non segue la sua passione per i computer e per Geeko coltiva la sua curiosità per l'astronomia (da cui deriva il suo nickname deneb_alpha).
Maruthi Prithivirajan, Head of ASEAN & IN Solution Architecture, Neo4j
Get an inside look at the latest Neo4j innovations that enable relationship-driven intelligence at scale. Learn more about the newest cloud integrations and product enhancements that make Neo4j an essential choice for developers building apps with interconnected data and generative AI.
Dr. Sean Tan, Head of Data Science, Changi Airport Group
Discover how Changi Airport Group (CAG) leverages graph technologies and generative AI to revolutionize their search capabilities. This session delves into the unique search needs of CAG’s diverse passengers and customers, showcasing how graph data structures enhance the accuracy and relevance of AI-generated search results, mitigating the risk of “hallucinations” and improving the overall customer journey.
“An Outlook of the Ongoing and Future Relationship between Blockchain Technologies and Process-aware Information Systems.” Invited talk at the joint workshop on Blockchain for Information Systems (BC4IS) and Blockchain for Trusted Data Sharing (B4TDS), co-located with with the 36th International Conference on Advanced Information Systems Engineering (CAiSE), 3 June 2024, Limassol, Cyprus.
Best 20 SEO Techniques To Improve Website Visibility In SERPPixlogix Infotech
Boost your website's visibility with proven SEO techniques! Our latest blog dives into essential strategies to enhance your online presence, increase traffic, and rank higher on search engines. From keyword optimization to quality content creation, learn how to make your site stand out in the crowded digital landscape. Discover actionable tips and expert insights to elevate your SEO game.
Essentials of Automations: The Art of Triggers and Actions in FMESafe Software
In this second installment of our Essentials of Automations webinar series, we’ll explore the landscape of triggers and actions, guiding you through the nuances of authoring and adapting workspaces for seamless automations. Gain an understanding of the full spectrum of triggers and actions available in FME, empowering you to enhance your workspaces for efficient automation.
We’ll kick things off by showcasing the most commonly used event-based triggers, introducing you to various automation workflows like manual triggers, schedules, directory watchers, and more. Plus, see how these elements play out in real scenarios.
Whether you’re tweaking your current setup or building from the ground up, this session will arm you with the tools and insights needed to transform your FME usage into a powerhouse of productivity. Join us to discover effective strategies that simplify complex processes, enhancing your productivity and transforming your data management practices with FME. Let’s turn complexity into clarity and make your workspaces work wonders!
Essentials of Automations: The Art of Triggers and Actions in FME
10.1.1.115.8580
1. Cell Breathing in CDMA Networks
Angela Amphawan
Abstract EbA EbB
The widespread deployment of wireless cellular = (1)
technology affects the traditional concept of channel N tA N tB
allocation and drives the necessity for novel load where Ebi/Nti is the signal to noise ratio received at base
balancing techniques. Various load-balancing schemes station i for the mobile under consideration, Ebi is the
have been proposed to assign channels to the cells such received bit energy and Nti is the spectral density of total
that the available channels are efficiently used and thus interference at base station i.
channel reuse, maximized. This is particularly important
in networks where traffic distribution is non-uniform. R
Some of the well-known load-balancing schemes include
the Directed Retry (DR), Channel Borrowing (CB), Cell Cell
Channel Borrowing without Locking (CBWL), Load A B
X
Balancing without selective borrowing (LBSB), Cell Forward and
Breathing and a number of others. Each possesses both reverse link
virtues and drawbacks. The objective of the paper is to handoff boundary
provide an assessment of the capabilities of Cell Soft handoff region
Breathing in optimal CDMA network management. The
paper studies the capabilities of cell breathing, its flaws Figure 1. A balanced forward and reverse link
and suggests possible solutions to the predicament. handoff boundary case for two cells A and B
Forward link handoff boundary is defined as the
1. Introduction contour of the mobile locations where
E cA EcB
Cellular communication networks divide the = (2)
geographical area into smaller hexagonal regions, called Io Io
cells. Over the last few years, a great deal of work has where Eci is the received pilot chip energy of i-th pilot and
been done to study optimal CDMA cell design whereby Io is the spectral density of the total power seen by the
the number of cell sites required is minimized while mobile.
maintaining the quality of service provided. The focus of It can be seen from (1) and (2) that, if the interference
these studies was on the maximization of cell radius for a levels are the same at both base stations and the same
given maximum power transmitted while ensuring that amount of power is transmitted on the pilot channel from
the quality of service in a specified percentage of the cell each base station, then the forward and reverse handoff
area was met. Most studies were under the presumption of boundaries will coincide; the boundary will be half way
uniform traffic distribution in each cell. between the two cell sites for a uniform propagation
In this paper, we analyze the impact of non-uniform model.
traffic distribution in different cells on cellular network As the reverse link traffic load is increased, the thermal
performance. Specifically, we are interested in noise at the base station increases. It is clear from (1) that
understanding how cell breathing performs load balancing the reverse link handoff boundary will move closer to the
under non-uniform traffic distribution. base station whose rise over thermal noise is greater.
Cell breathing is a mechanism that attempts to keep the Then, to balance the reverse and forward link handoff
forward and reverse link handoff boundaries balanced by boundaries, the pilot signal of the cell with greater base
changing the forward link coverage according to the station interference must be reduced. The mechanism
changes in the reverse link interference level. used to reduce pilot power on a cell based on the increase
Reverse link handoff boundary is defined as the in the reverse link interference level is referred to as cell
contour of mobile locations between neighboring cells breathing.
where the received signal to noise ratio at the two base A brief overview of the soft handoff process is given in
stations is the same. Referring to Figure 1, the reverse link Section 2. Positive impact of breathing on the forward
handoff boundary between cell sites A and B is the link is discussed in Section 3 while Section 4 discusses its
locations such that
2. negative impact. In Section 5, possible solutions are On the forward link, it is generally believed that once a
suggested. The paper is concluded in Section 6. given cell becomes heavily loaded, then the breathing
2. Overview of the Soft Hand over Process algorithm will reduce the cell’s coverage thereby
shedding some of the traffic to the surrounding cells
As discussed in Section 1, in IS95 CDMA systems the relieving the overloaded cell. Shedding of traffic from the
mobile measures the pilot Ec/Io from neighboring cell heavily loaded cell occurs because, as discussed in
sites. If a pilot is found whose Ec/Io is above a threshold Section 2, the soft handoff region on the side of the cell
called T_ADD, the mobile reports that pilot to the base with less loading shrinks. As a result, some of the
station. The pilot is to be included in the set of pilots in mobiles in the lightly loaded cell which were in soft
soft handoff referred to as the active set. On the other handoff with the heavily loaded cell will now go out of
hand, if the Eci/Io of a pilot in the active set is below a soft handoff with the heavily loaded cell. This releases
threshold called T_DROP for more than a certain time, some of the radio links from the heavily loaded cell that
the mobile will report that pilot to the base station. The serviced the users in soft handoff from the neighboring
pilot may then be removed from the active set. Therefore, cells. The released radio links can be used to support new
the pilot Ec/Io values as measured by the mobile users in the heavily loaded cell. The question is how
primarily determines the handoff region. Figure 1 shows much capacity increase may be expected in the heavily
the handoff boundary of two adjacent cell sites marked as loaded cell and what the impact will be to the overall cell
A and B. Since Io = IoA + IoB, where Ioi is the power quality.
spectral density of the total signal received from cell site i In a situation where one specific cell is heavily loaded
at the mobile and No is the thermal noise power spectral and all its surrounding cells are lightly loaded, if
density, then we get Io ≈ IoA near the edge of the soft breathing algorithm is activated then the handoff
handoff region closer to cell site A. In other words, the boundary of the heavily loaded cell will move further
edge of the soft handoff region near one cell site is inside that cell. In other words, the soft handoff boundary
primarily determined by the total signal power from that will move closer to the heavily loaded cell, Figure 2.
cell site. Suppose that cell A in figure 2 is heavily loaded and cell
Since the left side of the soft handoff region in Figure B lightly loaded. Then, in order to move the handoff
1 is determined by EcB/Io, i.e. the signal to interference boundary by an equal amount that the interference has
ratio seen on pilot B, then the left side of the handoff risen in a cell, the breathing algorithm will introduce an
region does not move when the pilot power of cell A is attenuation equal to α on the forward link of cell A in
reduced. The right edge of the soft handoff region response to a rise over thermal noise in cell A’s reverse
(Figure 1) however is determined by EcA/Io; therefore, as link. The pilot by EcA/Io seen from pilot of cell A will be
the pilot power of cell A is reduced, the right edge of the changed to
soft handoff region moves closer to cell site A as shown αEcA
in Figure 2. Therefore, if cell breathing is active, then as (3)
cell loading is increased in cell A and surrounding cell I oA + I oB + I oC
sites remain lightly loaded, the soft handoff region inside which is smaller than it used to be prior to breathing. The
the neighboring lightly loaded cell sites will reduce. Of α factor is due to breathing on cell A. Now the edge of
course, if the loading in all cell sites increase uniformly the soft handoff region closer to cell B will move away
then the breathing algorithm will reduce the soft handoff from cell B. Assuming that 35% of the cell area is in soft
region by roughly equal amount in all cells. In the next handoff and approximating the cell area by a circle, we
two sections, we investigate the impact of cell breathing have X=0.8R in Figure 1. We note that for large path loss
on network performance. exponents of 4, inside cell B the denominator of (3) will
Cell R Cell be dominated by IoB. Therefore, the handoff boundary
A B moves to the left in Figure 2 approximately 1 dB for each
dB of attenuation introduced by breathing on cell A.
As the handoff boundary is moved closer to cell A, the
X Forward and
reverse handoff
one benefit that may be obtained is that users that are
boundaries inside cell B and are in soft handoff with cell A may fall
after breathing out of soft handoff with cell A, relieving some capacity
from cell A to be used for users that are inside cell A.
Figure 2. Handoff boundary has moved closer to However, the attenuation α is applied to the total power
cell A due to loading on cell A going out of cell A, the overhead as well as the traffic
channels; therefore, we need to assess the impact of this
3. Positive Impact of Breathing on Forward attenuation on the traffic channels in cell A. The SNR
Link Performance seen by a mobile prior to attenuation introduced by
breathing is given by:
3. L gI or β j setting them equal we find that g’=1.1g. In other words,
SNR = ∑ (4) there is a 10% increase in forward gain in about 54% of
j =1 (1 − β ) I or + I oC + N o the cell area. Note that this 54% of the mobiles
where g is the fraction of total forward link power given correspond to the outer area of the cell. If we let Ioc/Ior
to a mobile referred to as the forward gain, L is the total =0.5, which corresponds to about 40% of the cell area,
number of multipath components captured by the mobile then substitution into (4) and (5) gives g’=1.14g.
from cell A, Ior is the total power received by the mobile Therefore, as mentioned above, the forward gains will
from cell A, βj is the fraction of the total power received increase for all mobiles as breathing introduces
by the mobile from cell A that is received on the j-th attenuation.
multipath component (which sum to 1 over all multipath In the two-path model described above, the increase in
j), IoC is the out of cell interference. Note that the first the forward gain for the traffic channels is initially less
component in the denominator of (4) is due to in-cell than the breathing attenuation, but as the forward gains
interference, from the multipath. Once the breathing are increased initially, the total power going out of the
attenuation is applied, the SNR seen by the mobile at the cell increases. Then, we can apply equation (5) iteratively
same location is given by to find out how much the forward gains will be increased
L λg ′I or β j in response to the increase of in cell interference.
SNR = ∑ (5) Therefore, eventually the traffic channel forward gains
j =1 (1 − β ) I or + I oC + N o will increase by the same amount as the breathing
The difference between (4) and (5) is in the attenuation attenuation, until the total traffic channel power going out
α and g’. In order to achieve the same SNR for the mobile of the cell becomes close to what it was prior to breathing
after breathing as before breathing, we need to increase attenuation. The output power after breathing will be less
g’, the fraction of power allocated to the mobile. In other due to lower power on overhead channels. Note that we
words, we need to determine g’ such that (4) and (5) are are assuming that the overhead channels (pilot, paging
equal in order to maintain the same FER. Therefore, the and synchronization) are not power controlled and their
forward gain of the traffic channel will increase to power is therefore reduced due to the breathing
achieve the same SNR as before. Note that in the actual attenuation. The reduction of total transmit power due to
system the reduction in the SNR due to breathing reduced power on the overhead channels will eventually
attenuation will cause the FER o f the users to increase. be used by new users and therefore the total transmit
The power control will then automatically increase the power will remain unchanged before and after breathing
forward gain of all users whose FER has increased in under heavy loading conditions. Of course, the mobile
order to lower their FER values to the desired values. whose forward gains were near their upper limit, their
If there is a single path seen by the mobile, it is then allocated power will decrease due to hitting the upper
clear from equations (4) and (5) that g’ must increase by limit of the forward gain.
Recall that based on the discussion in Section (2), the
an amount equal to α in order to maintain the SNR.
edge of the handoff region on the cell site i is determined
Suppose α=1dB. Then the soft handoff region will move
by the ratio Eci/Io. Based on the above discussion, the
by about 5% for the path loss exponent of 4 which means
power being transmitted from the heavily loaded cell site
now about 25% of the area of cells surrounding cell A
will remain almost constant after breathing. Then, the
will be in soft handoff with cell A instead of 35% of the
edge of the soft handoff region inside cell site A will not
area prior to breathing. In other words, 10% of mobiles in
move much because it is determined by Eci /Io which has
communication with cell A may be shed to other cells by
not changed. The edge of the soft handoff region inside
putting them out of soft handoff with cell A. Note that
cell B which is determined by EcA/Io, however is reduced
here we are assuming that all surrounding cells are lightly
because the pilot power transmitted from cell A is
loaded resulting in a net 10% shedding of traffic to the
reduced due to breathing. The reduction of soft handoff
surrounding cells. Throughout, we have assumed circular
area in cell B results in the reduction in the number of soft
cells and that cell A is surrounded by 6 other cells. Figure
handoff links that cell A must support for users inside cell
1 and 2 only show 2 cells for simplicity.
B. Therefore, the main sources of capacity increase in the
In a single path case, it is clear from equations (4) and
scenario where a heavily loaded cell is surrounded by a
(5) that there needs to be a dB for dB increase of forward
tier of lightly loaded cells is the shedding of traffic to
gain for each dB of breathing attenuation in order to
other cells and lower power on the overhead channels on
maintain the traffic channel SNR.
the heavily loaded cell. There will also be some
Next, consider the case where there are two multipath
additional capacity due to the mobiles, which were at their
components with the weaker paths’ power equal to half
upper limit of forward traffic gain; these mobiles’ power
the power of the stronger path, i.e. β1=0.67 and β2=0.33. cannot be increased which leave some room for new
Also, assume Ioc/Ior=0.25; separate simulations have traffic. But this additional capacity is at the cost of higher
shown that in about 54% of the cell area Ioc/Ior>0.25. In FER for some mobiles.
this case, by substituting into equations (4) and (5) and
4. Based on the above discussion, the forward link increases, thus deteriorating the cellular network
capacity of a heavily loaded cell, which is surrounded, by performance.
lightly loaded cells may be increased through cell
breathing. Cell breathing increases the capacity of the 5. Solutions
heavily loaded cell using two mechanisms. First, cell
breathing reduces power on the overhead channels equal Based on the above discussion breathing may provide
to the amount of breathing attenuation. For instance, if a small amount of capacity gain in very limited traffic
25% of the power had been allocated to the overhead scenarios. However, there may be an impact to call
channels and 1dB attenuation was applied to cell, then the quality if excessive breathing is allowed. The amount of
amount of power on overhead channels would reduce to breathing attenuation must be limited to a small amount
20% of total available power before breathing. This so as not to adversely impact the soft handoff region and
results in approximately 6% increase in forward link overall call quality.
capacity due to reduced overhead. The second The extent of cell breathing can be limited through the
mechanism that increases forward link capacity is by use of call admission control (CAC). The CAC
shedding mobiles to other lightly loaded cells. As mechanism is used to decide when a new call can be
discussed above, one dB attenuation will result in accepted. Schemes that are based on the measured noise
reduction of soft handoff region of the surrounding cells rise can be used to set the minimum cell size. Any new
from 35% to 25%. Therefore, under uniformly distributed calls will be blocked once the interference reaches a
traffic conditions there may be up to 10% increase in certain level.
capacity. Therefore, one dB of breathing may provide at From this, we can see that it is important to consider
most 15% capacity increase in a heavily loaded cell that is both network coverage and call blocking when planning a
surrounded by lightly loaded cell. CDMA network. Detailed network planning requires a
specialized CDMA planning tool. These tools use traffic
4. Negative Impact of Breathing on Forward information and propagation predictions to determine the
Link Performance coverage of the CDMA network.
Most 3G network planning tools utilize the ‘power
This capacity increase may, however, be at a cost of control loop’ method. Analytical techniques can also be
reduction in call reliability of calls because the soft used, but these are slow when the traffic load is high. It is
handoff region has been reduced. The reduced soft important for the tool to consider call blocking as well as
handoff may result in an increase in drop call rate. The network coverage. The tools can also be used to predict
reduced soft handoff region by breathing is particularly the soft-hand over regions.
problematic in networks whose soft handoff region has
already been reduced and optimized. 6. Conclusion
Lightly loaded cells The impact of cell breathing on the coverage of
CDMA cells was studied. It was shown that the main
Heavily loaded cell impact of cell breathing is reduced soft handoff region.
There is almost one dB reduction in soft handoff region
for each dB of breathing attenuation. Therefore, if cell
breathing is used to distribute traffic in certain
deployment/traffic scenarios, the impact of reduced soft
Lightly loaded cells
handoff region on call quality needs to be assessed. It
Figure 3a. No coverage holes develop when was shown that under very specific deployment
lightly loaded cells surround a heavily loaded conditions where one cell is heavily loaded and is
cell surrounded by lightly loaded cells, cell breathing might
provide a small increase in capacity. This capacity gain
may, however, be at some call quality cost. In order to
minimize impact to call quality, the amount of breathing
attenuation must be limited and controlled carefully.
Coverage holes
Figure 3b. Coverage holes develop when all cells References
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Also, if situation arises where all cells are heavily loaded, cellular systems: A systems perspective,
all cells will be simultaneously attenuated by the “Microwave Jl, 38 (7): 62-76, July 1995
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(Figures 3a and 3b). The probability of call dropping Load Balancing Algorithm for the Hot Cell
5. Problem in Cellular Mobile Networks”, 1997
IEEE
3. A. Jalali, “On Cell Breathing in CDMA
Networks”, IEEE 1998
4. Zhang Youngbing, “A New Adaptive Channel
Assignment Algorithm in Cellular Mobile
Systems”, 1999 IEEE