This document analyzes the capacity of MIMO wireless channels when accounting for impairments from physical transceiver hardware limitations. It is shown that when including the effects of transceiver impairments like non-linearities, phase noise, and quantization noise, the capacity of MIMO channels reaches a finite limit as SNR increases, rather than increasing without bound. This results in a zero multiplexing gain, unlike the ideal case without impairments. However, the relative capacity increase from MIMO over single-antenna channels remains at least as large when including impairments. Various figures are presented showing the capacity and multiplexing gain for different channel models and transceiver configurations. The document concludes by stating the analysis provides insights into understanding
Beamforming with per antenna power constraint and transmit antenna selection ...sipij
This document presents techniques for beamforming and antenna selection in cooperative distributed antenna systems using convex optimization. It formulates beamforming as a convex optimization problem to minimize total weighted transmit power while satisfying per-antenna power constraints and SINR thresholds. Antenna selection is also formulated as a convex problem to maximize channel capacity by selecting an optimal subset of antennas from available remote antenna units. Simulation results show that integrating beamforming into distributed antenna systems enhances performance and achieves a lower transmit power compared to non-beamforming techniques. The per-antenna power constraint also yields better performance than a sum power constraint.
This document examines using a Minimum-Mean-Square-Error (MMSE) adaptive algorithm reception technique for 6th derivative Ultra-wideband (UWB) Gaussian pulse shape signals compared to a conventional UWB Rake receiver. The MMSE adaptive algorithm is more efficient due to its ability to adapt to changes in the IEEE 802.15.3a UWB multipath channel model. Performance is evaluated for Direct-Sequence and Time-Hopping transmission schemes over the channel in the presence of narrowband interference and multiple access interference from other UWB users. Simulation results show the MMSE adaptive algorithm receiver has better performance than the UWB Rake receiver due to its adaptability.
An approach to control inter cellular interference using load matrix in multi...eSAT Journals
Abstract
This paper deals with reduction of inter cellular interference in Multi-carrier communication systems. In the past, Load Matrix(LM) is proposed to allocate power to different users in a network based upon Signal to noise plus interference ratio (SNIR) so as to reduce inter cellular interference and is observed for single carrier systems. In Multi carrier systems the SNIR is affected distinctly in each carrier thus a single SNIR for power allocation is not optimal. In this paper, to obtain the optimization of power allocation in Multi-Carrier system, Load Matrix coding with bifurcated SNIR (LM-BFSNIR) is proposed. Using this approach it is observed that inter cellular interference is reduced better when compared to a single carrier system evaluated over a 3GPP-LTE standard.
Keywords−Power allocation, Inter cellular interference, Multi-Carrier mobile Communication system.
New Adaptive Cooperative-MIMO for LTE Technologyijtsrd
Multiple Input Multiple Output (MIMO) systems have been widely used in an area of wireless cellular communication system, providing the both increased capacity and reliability. However, the use of multiple antennas in mobile terminals may not be very practical due to limited space and other implementation issues. In this paper, cooperative MIMO has been used in a way to optimise the implementation and working of conventional MIMO systems in terms of BER and Spectral Efficiency while maintaining a minimal number of antennas on each handset. Cooperative MIMO with V-BLAST transmission over Rayleigh flat fading channels and amplify and forward protocol with one relay node for modulation techniques like BPSK, QPSK, QAM using various decoding techniques has been analysed. Decoding algorithms like ZF, MMSE and ML have been analysed with respect to their BER performances. Since, there is throughput loss in cooperative MIMO due to extra resources required for relaying, adaptive modulation has been used with C-MIMO to meet the demands for high data rates in Long Term Evolution Network. Sukhreet Kaur | Dr. Amita Soni"New Adaptive Cooperative-MIMO for LTE Technology" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12919.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/12919/new-adaptive-cooperative-mimo-for-lte-technology/sukhreet-kaur
This document proposes a received signal strength (RSS) based vertical handoff scheme for k-tier heterogeneous wireless networks. It estimates RSS for different network tiers using empirical and statistical propagation models suited for the Indian urban and suburban environments. Based on the estimated RSS across different tiers, a vertical handoff algorithm is proposed that allows user equipment to switch between networks to maintain seamless connectivity based on RSS thresholds. The performance of the proposed RSS estimation and vertical handoff scheme is validated through simulations conducted using statistical data collected from field measurements.
BEHAVIOUR OF OFDM SYSTEM AND REDUCTION OF ITS PAPR BY USING SELECTIVE MAPPING...IAEME Publication
The OFDM technique divides the total bandwidth into many narrow sub-channels and sends data in parallel. It has various advantages, such as high spectral efficiency, immunity to impulse interference and, frequency selective fading without having powerful channel equalizer. But one of the major drawbacks of the OFDM system is high PAPR. OFDM signal consists of lot of independent modulated subcarriers, which created the problem of PAPR. It is impossible to send this high peak amplitude signals to the transmitter without reducing peaks. So we have to reduce high peak amplitude of the signals before transmitting. Communication is one in all the numerous features of existence. A new DSI-SLM method for PAPR reduction in OFDM system state that the phase sequence and dummy sequences added to the signal improves the PAPR reduction in OFDM signals whereas less hardware resources and less time are required to achieve the desired result.
Spectrum sharing paradigm (SSP) has recently emerged as an attractive solution to provide capital expenditure (CapEx) and operating expenditure (OpEx) savings and to enhance spectrum utilization (SU). However, practical issues concerning the implementation of such paradigm are rarely addressed (e.g., mutual interference, fairness, and mmWave base station density). Therefore, in this paper, we proposed ultra-reliable and proportionally fair hybrid spectrum sharing access strategy that aims to address the aforementioned aspects as a function of coverage probability (CP), average rate distributions (ARD), and the number of mmWave base stations (mBSs). In this strategy, the spectrum is sliced into three parts (exclusive, semi-pooled, and fully pooled). A typical user that belongs to certain operator has the right to occupy a part of the spectrum available in the high and low frequencies (28 and 73 GHz) based on an adaptive multi-state mmWave cell selection scheme (AMMC-S) which associates the user with the tagged mBS that offers a highest SINR to maintain more reliable connection and enrich the user experience. Numerical results show that significant improvement in terms of ARD, CP, fairness among operators, and maintain an acceptable level of mBSs density.
Error Rate Analysis of MIMO System Using V Blast Detection Technique in Fadin...IJERA Editor
Wireless communication system with multi- antenna arrays has been a field of intensive analysis on the last years. The appliance of multiple sending antennas and Receiving Antennas either side will considerably enhance the data rate and rate. The review of the performance limitations of MIMO system becomes vital since it will provide lot ideas in understanding and planning the important life MIMO systems. Vertical Bell Laboratories layered space Time (V-BLAST). The thought behind Multiple Input and Multiple Output system is that the signals on the transmitter antennas at one finish and also the receiver antennas at the opposite finish are correlative in such how that the performance (Bit Error Rate or BER) or the info rate (bits/sec) of the wireless communication system for every MIMO subscriber are improved. During this paper we tend to are proposing a technique that evaluates the performance of V-BLAST MIMO system in several thought of Rayleigh attenuation surroundings to urge higher performance of the system. In V- BLAST MIMO system a number of linear detection techniques will be used for interference cancellation. At this point we are using MMSE-IC for the same. Our expected system provide higher error rate performance with the used of matched filter at receiver aspect .The projected system compared within the presence of AWGN. Now matched filter applied on V- BLAST MIMO with MMSE-IC system in fading diversity surroundings.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
With the rise of data-intensive mobile applications, network operators must find ways to increase network capacity to meet demand. MIMO (Multiple-Input Multiple-Output) techniques, which use multiple antennas at the transmission and reception ends, have the potential to significantly boost network throughput through spatial multiplexing. However, optimizing networks for MIMO's full benefits presents challenges, as MIMO works best under rich scattering conditions and requires accurate measurement of multipath environments. Real-world RF measurements tailored for MIMO networks can help operators overcome these challenges and maximize throughput gains from MIMO without additional spectrum or infrastructure.
This paper proposes a technique to reduce peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) signals using polar codes in a WiMAX architecture. A polar encoder is introduced which generates multiple candidate OFDM symbols from different polar codewords that share the same information bits but have different random bits. The symbol with the lowest PAPR is then selected for transmission. Simulation results show the proposed method can achieve over 5 dB PAPR reduction without increasing bit error rate, improving power amplifier efficiency.
Iaetsd adaptive modulation in mimo ofdm system for4 gIaetsd Iaetsd
This paper proposes applying hybrid adaptation techniques in MIMO OFDM systems to improve spectral efficiency and reduce transmit power. It first analyzes the bit error rate of M-QAM modulation in OFDM systems with different numbers of subcarriers. Channel estimation is performed using MMSE, which estimates the channel with less error than LS. Feedback from channel estimation is then used with hybrid adaptation techniques. Simulation results show MMSE has lower MSE and symbol errors than LS estimation.
Effect of Channel Variations on the Spectral Efficiency of Multiuser Diversit...IDES Editor
This document analyzes how the spectral efficiency of a multiuser diversity MIMO system is affected when the channel type deviates from Rayleigh fading to Nakagami-m fading. It simulates a system with different MIMO configurations and compares the average user data rates under absolute and proportional SNR scheduling schemes at 0dB, 10dB, and 20dB. The results show that user data rates decrease the most at 0dB SNR as the channel type changes from Rayleigh to Nakagami-m fading, with higher m values leading to greater losses.
Satellite Telemetry Data Transmission Immunity from the ASI and Jamming Using...IOSRJECE
In the satellite telemetry command, controlling the power of the uplink signal, radiated away from the Earth to the spacecraft and downlink signal, radiated toward the Earth form the spacecraft is very important. The Uplink is transmitted at high power because of the unlimited power, while downlink should be controlled in power because of limited spacecraft power resources. This results in a lower Power Spectral Density (PSD) for the downlink and higher PSD for the uplink, which in many cases the uplink power due to be strong enough to reach the satellites at GEO would often also violate the PSD limits in the other orbits satellite telemetry signals like LEO. In addition due to long distance between the Earth and satellite, the received signals at the both terrestrial and transponder receivers are extremely week and strongly influenced by intentional interference (like jamming) or inadvertent interferences (such as the ASI). Spreading spectrum can solve the PSD problems for both directions but consumes a wide bandwidth. Fortunately, signals can be distinguished by using different spreading codes, allowing for CDMA. The Pseudo Noise (PN) spreading codes allow using many satellites or users (located in one satellite) the same frequency with overlapping signals simultaneously and also range measurement as useful ability to track the spacecraft in the space by the expanding value of the PN codes (Doppler Shift).[1] This paper specially considers to satellite telemetry data transmission immunity from the interference using Direct Sequence Spread Spectrum (DSSS) based on CDMA namely DS-CDMA (Direct Sequence-CDMA) by the unique properties correlation functions of the Gold and M-Sequence codes. Also the codes are examined in the fading channels, Reyleigh and AWGN, in terms of the BER vs. Eb/No to compare the practical results with theoretical values.
Performance Comparison of Multi-Carrier CDMA Using QPSK and BPSK ModulationIOSR Journals
Abstract: MC-CDMA (Multi Carrier Code Division Multiple Access) plays an important role in modern wireless communications. Modern communication required an efficient spectrum usage and capacity and throughput.MC-CDMA provided the solution of these problems. MIMO refers to links with multiple antennas at the transmitter and receiver side. CDMA systems combined with multiple antennas is a promising technique, beyond 3G and 4G wireless communications. MIMO provides spatial diversity, which mitigates the fading. The usage of multiple antennas can significantly improve the performance of wireless communication system. This work also derives simulation through MATLAB of average bit error rate verses bit energy to noise ratio of multicarrier code division multiple access over Rayleigh channel using QPSK and BPSK modulation additive white Gaussian noise. Keywords: AWGN,BER,MC-CDMA, QPSK Modulation, Rayleigh Channel.
An Efficient Performance of Mimo - Ofdm Based Cognitieve Radio System for Arr...IOSR Journals
Abstract: The wireless channel is central within this context, thus estimating the channel is the key to make CR operational, taking in consideration that the transmission-reception technology is available. In this thesis, we design a MIMO system using OFDM modulation technology to transmit and receive two signals over the mobile wireless channel. First formulate the pilot design as a new optimization problem. We use MIMO concept to enhance system capacity and robustness of the wireless transmission. In Multi-Input Multi-Output (MIMO) based cognitive radio (CR) systems, with the increasing demand for data rate and reliability in Wireless communicationsand devices, several issues become very important like bandwidth efficiency, quality of service and radio coverage. In this new scheme, adaptive arrays are group-selected in the spatial domain. Simulation shows that the proposed system can get significant performance improvements over the conventional array based OFDM systems over frequency-selective multipath fading channels with cognitive radio (CR) system. Keywords: Cognitive radios, MIMO, OFDM, and Joint transmit and receive group selected arrays.
Resource Allocation in MIMO – OFDM Communication System under Signal Strength...Kumar Goud
Abstract: - Multiple Inputs and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to attain high capability on the propagation setting. The aim of this paper is that the adaptive resource allocation in MIMO-OFDM system uses the water filling formula. Water filling answer is enforced for allocating the ability so as to extend the data rate. The overall system capability is maximised subject to the constraints on total power, signal to noise quantitative relation, and proportionality. Channel is assumed as a flat attenuation channel and therefore the comparison is created for various 2×2, 2×3, 3×2 and 4×4 MIMO-OFDM systems and water filling formula with allotted power. Supported the capability contribution from the relaying terminal, a brand new parameter referred to as cooperation constant is introduced as an operate of the relaying sub channel. This parameter is employed to switch the target parameter of the subcarrier allocation procedure. Fairness-oriented [Fading Channel] and throughput-oriented [Near finish Channel] algorithms square measure elite from the literature to check the planned technique. Each algorithms square measure changed to use the mean of cooperation constant within the objective parameter of the subcarrier allocation procedure and shown to own a much better total turnout with none sacrifice.
Keywords - MIMO-OFDM; Water filling Algorithm; Subcarrier Resource Allocation
MIMO channels: optimizing throughput and reducing outage by increasing multip...TELKOMNIKA JOURNAL
The two main aims of deploying multiple input multiple out (MIMO) are to achieve spatial diversity (improves channel reliability) and spatial multiplexing (increase data throughput). Achieving both in a given system is impossible for now, and a trade-off has to be reached as they may be conflicting objectives. The basic concept of multiplexing: divide (multiplex) transmit a data stream several branches and transmit via several (independent) channels. In this paper, we focused mainly on achieving spatial multiplexing by modeling the channel using the diagonal Bell Labs space time scheme (D-BLAST) and the vertical Bell Labs space time architecture (V-BLAST) Matlab simulations results were a lso given to further compare the advantages of spatial multiplexing.
1) The document presents the results of a stability analysis of a reinforced earth wall for the approach road of a rail over bridge along a national highway.
2) The maximum height of the embankment is 7m, and stability is a concern due to weak subgrade soil. Stability analysis using Slope/W software indicates a factor of safety below recommended values without reinforcement.
3) The addition of geosynthetic reinforcement in the form of geogrids placed at various depths and tensions within the embankment fill improves the factor of safety. The optimum reinforcement configuration is found to be 3 geogrid layers.
This document compares the performance of IPv4 and IPv6 over MPLS networks. It summarizes the results of simulations run using OPNET 14.5 that evaluated packet delay, packet loss, and throughput for IPv4 and IPv6 over MPLS. The simulations found that IPv6 over MPLS exhibited higher packet loss, higher throughput, and higher delay compared to IPv4 over MPLS which had lower throughput and delay with less dropped packets. Therefore, IPv6 may be suitable for applications requiring high bandwidth but not for real-time applications due to its higher delays and packet loss.
This document provides an overview of digital image steganography and steganalysis. It discusses various image steganography techniques including least significant bit modification in the spatial domain, and algorithms like JSteg and F5 that operate in the transform domain. It also covers hybrid techniques like patchwork and spread spectrum. The document compares the techniques based on parameters like invisibility, bit rate, and robustness. Finally, it discusses steganalysis methods for detecting hidden information in images, including techniques based on higher-order image statistics.
This document summarizes a survey on balancing network load using geographic hash tables. It discusses how geographic hash tables are used to store and retrieve data from nodes in a wireless network. Two approaches to balancing the network load are proposed: 1) An analytical approach that adds new nodes to servers when load exceeds thresholds. 2) A heuristic approach that moves data between nodes to prevent any single node from receiving too many requests. The approaches aim to extend network life by distributing load more evenly without changing underlying georouting protocols.
This document provides a review of optimization techniques for the wire electrical discharge machining (WEDM) process. It begins with an introduction to WEDM, describing the working principle and important process parameters like pulse width, time between pulses, servo reference voltage, and wire tension. The document then reviews literature on optimization methods that have been used to maximize material removal rate while minimizing electrode wear rate. Specifically, it discusses two studies that used Taguchi's design of experiments approach and desirability functions to optimize cutting conditions for different materials like minimizing wear rate and maximizing material removal rate in WEDM.
This document provides a comprehensive review of existing works in offline handwritten character recognition. It discusses the three major stages of any character recognition system: preprocessing, feature extraction, and classification. For preprocessing, it describes techniques like binarization, filtering, and morphological operations that are used to improve image quality. For feature extraction, it discusses various methods used to represent characters, including global transformations, statistical representations, and geometrical/topological features. Wavelet transforms are highlighted as a commonly used feature extraction technique. Finally, it provides an overview of literature on methods used in each stage of offline handwritten character recognition systems.
This document summarizes research into improving transient stability in power transmission systems using a Static VAR Compensator (SVC) with a hybrid PI-Fuzzy Logic controller. It begins with an introduction to Flexible AC Transmission Systems (FACTS) and the role of SVC devices in voltage control and reactive power compensation. It then describes modeling an SVC and the operating principles of conventional PI control. The limitations of PI control for nonlinear systems are discussed. The document proposes a hybrid PI-Fuzzy Logic controller to combine the advantages of both. Simulation results using MATLAB on a 2-machine 3-bus test system show the hybrid controller improves performance during disturbances over PI or Fuzzy Logic control alone.
This document presents a new segmentation technique for brain MRI images and compares it to existing techniques. The proposed technique is a two-stage brain extraction algorithm (2D-BEA) that first removes noise and enhances brain boundaries, then uses morphological operations to extract the brain region. It is shown to accurately extract the brain from MRI images. The technique is then compared to other segmentation methods like thresholding, edge detection, fuzzy c-means clustering, and k-means clustering. The results demonstrate that the 2D-BEA technique outperforms these other methods in effectively segmenting the brain region from MRI images.
Intelligent Fault Identification System for Transmission Lines Using Artifici...IOSR Journals
Transmission and distribution lines are vital links between generating units and consumers. They are
exposed to atmosphere, hence chances of occurrence of fault in transmission line is very high, which has to be
immediately taken care of in order to minimize damage caused by it. This paper focuses on detecting the faults
on electric power transmission lines using artificial neural networks. A feed forward neural network is
employed, which is trained with back propagation algorithm. Analysis on neural networks with varying number
of hidden layers and neurons per hidden layer has been provided to validate the choice of the neural networks
in each step. The developed neural network is capable of detecting single line to ground and double line to
ground for all the three phases. Simulation is done using MATLAB Simulink to demonstrate that artificial
neural network based method are efficient in detecting faults on transmission lines and achieve satisfactory
performances. A 300km, 25kv transmission line is used to validate the proposed fault detection system.
Hardware implementation of neural network is done on TMS320C6713.
Fault detection and diagnosis of high speed switching devices in power invertereSAT Journals
Abstract
Power electronic based inverters are the major components in industry. A fault diagnostics framework composed of a pattern recognition system, having machine learning technology as its integral part is utilized for failure detection of different switches and tracing multiple types of faults in an inverter. Hardware point of view power electronics inverter can be considered to be the weakest link. Hence, this work is carried on detecting faults and classifies which switches in the inverter cause the fault. Diagnosis can help to avoid unplanned breakdown, to make possible to run an emergency operation in case of a fault. On the basis of theoretical foundations of electronic power inverter a simulation model has been developed to simulate the healthy condition and all single-switch open circuit faults. The generated signal is processed using Discrete Wavelet Transform (DWT) and Fuzzy Inference Logic (FIL). A smart and accurate classification of faults is obtained using simulation results, which are tested on a wide operation domain and various load conditions.
Keywords: Fault Diagnosis, DWT, Fuzzy Logic, Artificial Intelligence (AI).
1) The document reviews land acquisition policies and processes used in various countries around the world. It examines studies that analyzed land acquisition practices in countries like India, China, Nigeria, Malaysia, Mozambique, Ghana, Zambia, Tanzania, Bangladesh, and Vietnam.
2) The studies found that compensation provided to land owners for acquisition varied significantly between countries and sometimes within countries. Valuation methods also differed, though market value was commonly used.
3) No single best practice for land acquisition and compensation was identified. The document concludes that developing a transparent framework informed by principles, processes, and mechanisms could help improve compensation systems.
The document discusses the use of shunt active filters to mitigate current harmonics in power systems. It analyzes the performance of a shunt active filter controlled by a PI controller and fuzzy logic controller (FLC) under normal and increased load conditions with balanced and unbalanced source voltages. The main points are:
A) Shunt active filters inject compensating current to make the source current sinusoidal and maintain unity power factor.
B) Both PI and FLC controllers perform well under balanced voltages but FLC provides better compensation under unbalanced voltages.
C) The FLC with a triangular membership function offers superior results compared to the PI controller in mitigating current harmonics.
This document summarizes a research paper analyzing the sustainability opportunities and challenges of the biofuels industry in India. The paper aims to answer three questions: 1) What are some significant sustainability opportunities and challenges of the biofuels industry? 2) What is the current state of biofuel operations in India? 3) What initial steps can be taken toward sustainable biofuel development? The response analyzes strategic sustainable development approaches and tools like the Natural Step Framework. Key points discussed include economic, environmental and social sustainability assessments of biomass and biofuels, including issues of profitability, efficiency, equity, energy balance, greenhouse gas emissions and life cycle assessments. Challenges in implementing ethanol blending programs in India like taxation and availability of
This document summarizes a study on the body composition of children participating in regular football, cricket, and gymnastics training. The study aimed to compare the anthropometric and body composition status of children in these three sports. Body composition measurements including body fat percentage, fat mass, and lean mass were taken for children in each sport. Statistical analysis found that footballers had significantly lower body fat percentage and fat mass than cricketers but did not differ significantly in lean mass. Footballers also had significantly lower body fat percentage and fat mass than cricketers as well as significantly higher lean mass. Gymnasts had significantly lower body fat percentage and fat mass than cricketers but did not differ significantly in lean mass. The study concluded that footballers generally had a better body
This document provides details on calculating various losses that occur in high voltage underground power cables, including dielectric losses, conductor losses, and sheath losses. It presents formulas to calculate voltage-dependent and current-dependent dielectric losses, as well as ohmic conductor losses and sheath eddy current and circulating current losses. The document also provides methods to calculate cable parameters like inductance, impedance, and mutual impedances between conductors and screen. It describes using these calculations and ETAP modeling to analyze losses in an existing 33kV cable network and determine that installing VAR compensators could reduce total daily power losses by approximately 2471 kW.
The document discusses improving power system performance using Flexible AC Transmission System (FACTS) devices. It describes three types of FACTS devices: Static Var Compensator (SVC), Thyristor Controlled Series Compensator (TCSC), and Unified Power Flow Controller (UPFC). The SVC and TCSC are able to control voltage and improve the voltage profile. Simulations showed adding FACTS devices decreased power losses and improved the voltage level. The UPFC can simultaneously control parameters like line impedance, voltage, and phase angle to regulate power flow.
This document presents a study on the optimal design of a bi-layer perforated electromagnetic shield using an improved particle swarm optimization (IPSO) algorithm. The study formulates the problem of minimizing the effective mass of the shield while meeting a target shielding effectiveness. It describes using a bi-layer of copper and permalloy with air holes to reduce mass. The IPSO algorithm is applied to determine the optimum thickness of each layer to minimize the effective mass subject to achieving an acceptable shielding effectiveness level based on standards. Simulation results show the proposed IPSO method finds solutions that provide shielding effectiveness comparable to standard values.
This document discusses the design, analysis, and feasibility testing of a center-mounted suspension system. It begins with an introduction to conventional suspension systems and their limitations. The proposed center-mounted system aims to improve vehicle balance in all terrains by directly attaching the suspension to the vehicle's central chassis. The document then reviews different suspension system types and analyzes the proposed system's working principles and mathematical calculations. Finally, stress analysis using ANSYS software demonstrates the advantages of the center-mounted design in absorbing shocks during turns and on bumpy roads. In conclusion, the proposed system maintains vehicle balance better than conventional designs through its unique center-attached configuration.
This document proposes a bandwidth degradation technique to reduce call dropping probability in mobile
networks. It aims to dynamically adjust bandwidth allocation to multiple users according to network conditions
to increase utilization. The technique allows for degrading the quality of existing calls to admit new calls
while maintaining quality of service. Key performance metrics analyzed include degradation ratio, degraded
bandwidth, throughput, and propagation delay. The approach is intended to be implemented using MATLAB
to simulate various mobility patterns for verification.
This document studied the nasal parameters of two ethnic groups in Nigeria - the Ibibio and Yakurr peoples. It measured the nasal length, width and indices of 400 subjects (200 from each group, split evenly between males and females). The results found significant ethnic and gender differences in all nasal parameters. Specifically, Ibibio males had platyrrhine noses while Ibibio females had mesorrhine noses. Yakurr males had mesorrhine noses while Yakurr females had platyrrhine noses. Nasal indices thus varied significantly between the groups and could be useful for ethnic and gender differentiation.
1. The document proposes an energy efficiency optimization power allocation (EEOPA) algorithm for multiuser multiple-input multiple-output (MU-MIMO) systems to improve energy efficiency.
2. In existing TDD MU-MIMO systems, high bit error rates result from imperfect channel state information. The proposed EEOPA algorithm aims to address this by optimizing power allocation.
3. The algorithm involves using quadrature amplitude modulation (QAM) and adapting the modulation scheme based on channel quality measurements to improve energy efficiency while maintaining low bit error rates. Simulation results show the algorithm can calculate SNR and BER to validate the energy efficiency gains.
A Potent MIMO–OFDM System Designed for Optimum BER and its Performance Anal...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
MIMO-OFDM (Multi Input Multi Output- Orthogonal Frequency Division Multiplexing) system is very popular technique for mobile communication. We found that Ergodic channel capacity has some limitation in MIMO-OFDM system. So Ergodic channel capacity optimization is necessary to improve the performance of MIMO-OFDM System.
Adaptive Resource Allocation in MIMO-OFDM Communication Systemijsrd.com
Multiple Input and Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) system have the potential to achieve very high capacity depending on the propagation environment. The objective of this paper is the adaptive resource allocation in MIMOOFDM system using the waterfilling algorithm. Water filling solution is implemented for allocating the power in order to increase the channel capacity. The total system capacity is maximised subject to the constraints on total power, signal to noise ratio, and proportional fairness. Channel is assumed as a flat fading channel and the comparison is made for different 2x2, 2x3, 3x2 and 4x4 MIMO-OFDM systems using waterfilling algorithm with allocated power. Also in order to prove that the MIMOOFDM with waterfilling algorithm provides the best performance a comparison with various SISO - OFDM is done.
IRJET- Performance Analysis of MIMO-OFDM System using Different Antenna Confi...IRJET Journal
This document analyzes the performance of a MIMO-OFDM wireless communication system using different antenna configurations through simulation in MATLAB. It finds that the system performs better when diversity is increased at both the transmitter and receiver sides. Specifically, it shows that bit error rate decreases and signal-to-noise ratio increases as the number of receiving antennas is increased when using BPSK modulation over an AWGN channel. The performance of MIMO-OFDM is evaluated for different detection methods and antenna configurations, and zero-forcing with successive interference cancellation is found to improve bit error rate compared to other techniques.
Enhancing Performance for Orthogonal Frequency Division Multiplexing in Wirel...IRJET Journal
The document discusses enhancing the performance of Orthogonal Frequency Division Multiplexing (OFDM) in wireless systems. It proposes using a technique called Selective Level Mapping (SLM) to reduce the peak-to-average power ratio (PAPR) of OFDM signals. PAPR reduction is important for OFDM systems to improve power amplifier efficiency. The document describes a "Class-III SLM scheme" that can generate multiple alternative OFDM signal sequences using only one inverse fast Fourier transform, helping to reduce complexity. It proposes a selection method for rotation values that can achieve optimal PAPR reduction while balancing the load across components. Simulation results show the proposed method achieves better PAPR reduction performance than conventional methods
An investigation-on-efficient-spreading-codes-for-transmitter-based-technique...Cemal Ardil
This document summarizes research on efficient spreading codes for transmitter-based techniques to mitigate interference in time division duplex code division multiple access (TDD/CDMA) downlink systems. It investigates bitwise and blockwise multiuser transmission schemes that transfer complexity to the transmitter. Different spreading codes are evaluated based on correlation properties to determine suitability for techniques like precoding, pre-rake, and rake diversity. Performance is measured by bit error rate with varying numbers of users to identify the most efficient codes for interference mitigation.
This document summarizes recent advances in wireless communication through the implementation of OFDM-MIMO systems. It discusses how OFDM can transmit multiple signals simultaneously using orthogonal subcarriers to improve data rates. MIMO uses multiple antennas at the transmitter and receiver to provide diversity gain and increase capacity. The combination of OFDM and MIMO (OFDM-MIMO) results in increased data rates and efficiency by overcoming problems like frequency selective fading. It then describes how OFDM-MIMO systems can transmit a single signal using transmit diversity and relay selection with decode-and-forward or amplify-and-forward protocols to further improve performance. Simulations show the OFDM-MIMO system achieves a lower bit error rate than
Channel Estimation Techniques in MIMO-OFDM LTE SystemsCauses and Effects of C...IJERA Editor
There is an increasing demand for high data transmission rates with the evolution of the very large scale integration (VLSI) technology. The multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) systems are used to fulfill these requirements because of their unique properties such as high spectral efficiency, high data rate and resistance towards multipath propagation. MIMO-OFDM systems are finding their applications in the modern wireless communication systems like IEEE 802.11n, 4G and LTE. They also offer reliable communication with the increased coverage area. The bottleneck to the MIMO-OFDM systems is the estimation of the channel state information (CSI). This can be estimated with the help of any one of the Training Based, Semiblind and Blind Channel estimation algorithms. This paper presents various channel estimation algorithms, optimization techniques and their effective utilization in MIMO-OFDM for modern wireless LTE systems.
Optimal Channel and Relay Assignment in Ofdmbased Multi-Relay Multi-Pair Two-...ijcnes
Efficient utilization of radio resources in wireless networks is crucial and has been investigated extensively. This letter considers a wireless relay network where multiple user pairs conduct bidirectional communications via multiple relays based on orthogonal frequency-division multiplexing (OFDM) transmission. The joint optimization of channel and relay assignment, including subcarrier pairing, subcarrier allocation as well as relay selection, for total throughput maximization is formulated as a combinatorial optimization problem. Using a graph theoretical approach, we solve the problem optimally in polynomial time by transforming it into a maximum weighted bipartite matching (MWBM) problem. Simulation studies are carried out to evaluate the network total throughput versus transmit power per node and the number of relay nodes
Performance enhancement of maximum ratio transmission in 5G system with multi...IJECEIAES
This document summarizes a research paper that proposes improving the performance of 5G systems using maximum ratio transmission (MRT) with multi-user multiple-input multiple-output (MU-MIMO) by incorporating weighted overlap-add (WOLA) precoding. It compares the proposed WOLA-MRT system to a standard MRT system with orthogonal frequency-division multiplexing (OFDM). Simulation results show the proposed system achieves approximately 60% higher throughput and a 2% lower bit error rate than the standard system, demonstrating significant performance enhancements for 5G massive MIMO networks.
IMPLEMENTATION OF LINEAR DETECTION TECHNIQUES TO OVERCOME CHANNEL EFFECTS IN ...IJCI JOURNAL
Spatial diversity technique enables improvement in quality and reliability of wireless link. Antenna
diversity along with understanding effects of channel on transmitted signal and methods to overcome the
channel impairment plays an important role in wireless communication where sharing of channel occurs
between users. In this paper single input single output system (SISO) is compared with multiple input
multiple output system (MIMO) in terms of bit error rate performance. Bit error rate performance is also
evaluated for MIMO with least squares (LS) and Minimum mean square error (MMSE) linear detection.
Further analysis and simulation is done to understand the effect of channel imperfections on BER.
Multicarrier modulation can be implemented by using Orthogonal Frequency Division Multiplexing (OFDM) to achieve utmost bandwidth exploitation and soaring alleviation attributes profile besides multipath fading. To support delay sensitive and band bandwidth demanding multimedia applications and internet services, MIMO in addition with other techniques can be used to achieve high capacity and reliability. To obtain high spatial rate by transmitting data on several antennas by using MIMO with OFDM results in reducing error recovery features and the equalization complexities arise by sending data on varying frequency levels. Three parameters frequency OFDM, Spatial (MIMO) and time (STC) can be used to achieve diversity in MIMO-OFDM. This technique is dynamic and well-known for services of wireless broadband access. MIMO if used with OFDM is highly beneficial for each scheme and provides high throughput. There are several space time block codes to exploit MIMO OFDM; one of the techniques is called Alamouti Codes. The paper investigates adaptive Alamouti Codes and their application in IEEE 802.11n.
This document analyzes multipath fading profiles in multiple access system grids using orthogonal frequency division multiple access (OFDMA) systems. It discusses how OFDMA systems exploit multiuser diversity and frequency selectivity to achieve high spectral efficiencies but require feedback and are sensitive to delays. It proposes a non-iterative method for resource allocation that has lower complexity than previous methods and simulates higher data rates. It also analyzes popular feedback schemes and the impact of feedback delays on system throughput.
A Review of Relay selection based Cooperative Wireless Network for Capacity E...IRJET Journal
This document discusses relay selection in cooperative wireless networks to enhance network capacity. It reviews cooperative communication techniques like amplify-and-forward and decode-and-forward that achieve spatial diversity without requiring multiple antennas on a device. The selection of relay nodes has a significant impact on the total network capacity. It aims to study cooperative relay node assignment that allows multiple source-destination pairs to compete for the same pool of relay nodes, with each pair able to be assigned multiple relays.
An investigation of Max-Min Fairness Power Control in Cell-Free Massive MIMO ...IRJET Journal
1) The document investigates the impact of max-min fairness power control on the performance of cell-free massive MIMO (CF-mMIMO) networks and small-cell mMIMO (SC-mMIMO) networks.
2) It derives closed-form expressions for the downlink and uplink throughput of CF-mMIMO networks using max-min fairness power control algorithms.
3) The numerical results show that the throughput of CF-mMIMO networks outperforms SC-mMIMO networks, and additional antennas at access points can improve throughput in CF-mMIMO networks compared to SC-mMIMO networks.
The document discusses how MIMO techniques can increase the capacity of LTE networks by transmitting multiple data streams simultaneously. It describes the key MIMO transmission modes used in LTE, including closed-loop and open-loop modes. Optimizing networks for MIMO is challenging and requires accurate measurement of multipath conditions to maximize throughput gains. Real-world RF measurements designed specifically for MIMO networks can help operators overcome optimization challenges and achieve the full benefits of MIMO in LTE.
Pilot Decontamination over Time Frequency and Space Domains in Multi-Cell Ma...IJECEIAES
In this article, we show that Pilot contamination problem can be seen as a source separation problem using time, frequency, and space domains. Our method capitalizes on a nonunitary joint diagonalization of spatial quadratic time-frequency (STFD) signal representation to identify the desired and interfering users. We first compute the noise subspace from the STFD matrices selected appropriately. Secondly, we use the noise subspace obtained to estimate the Elevation (El) and the Azimuth (Az) angles for which the MUSIC cost function is maximized. Numerical simulations are provided to illustrate the effectiveness and the behavior of the proposed approach.
Spectrum Is A Limied And Valuable Resource EssayErin Rivera
This document discusses improving the error performance of spatially multiplexed multiple-input multiple-output (MIMO) systems over Weibull-gamma fading channels. It proposes using ordered successive interference cancellation with minimum mean square error detection (MMSE-OSIC) and its variation (MMSE-OSIC2) to achieve better error performance than maximum likelihood detection at lower complexity. Simulation results are presented to evaluate the error performance of MIMO systems using different detection techniques under Weibull-gamma composite fading conditions.
This document provides a technical review of secure banking using RSA and AES encryption methodologies. It discusses how RSA and AES are commonly used encryption standards for secure data transmission between ATMs and bank servers. The document first provides background on ATM security measures and risks of attacks. It then reviews related work analyzing encryption techniques. The document proposes using a one-time password in addition to a PIN for ATM authentication. It concludes that implementing encryption standards like RSA and AES can make transactions more secure and build trust in online banking.
This document analyzes the performance of various modulation schemes for achieving energy efficient communication over fading channels in wireless sensor networks. It finds that for long transmission distances, low-order modulations like BPSK are optimal due to their lower SNR requirements. However, as transmission distance decreases, higher-order modulations like 16-QAM and 64-QAM become more optimal since they can transmit more bits per symbol, outweighing their higher SNR needs. Simulations show lifetime extensions up to 550% are possible in short-range networks by using higher-order modulations instead of just BPSK. The optimal modulation depends on transmission distance and balancing the energy used by electronic components versus power amplifiers.
This document provides a review of mobility management techniques in vehicular ad hoc networks (VANETs). It discusses three modes of communication in VANETs: vehicle-to-infrastructure (V2I), vehicle-to-vehicle (V2V), and hybrid vehicle (HV) communication. For each communication mode, different mobility management schemes are required due to their unique characteristics. The document also discusses mobility management challenges in VANETs and outlines some open research issues in improving mobility management for seamless communication in these dynamic networks.
This document provides a review of different techniques for segmenting brain MRI images to detect tumors. It compares the K-means and Fuzzy C-means clustering algorithms. K-means is an exclusive clustering algorithm that groups data points into distinct clusters, while Fuzzy C-means is an overlapping clustering algorithm that allows data points to belong to multiple clusters. The document finds that Fuzzy C-means requires more time for brain tumor detection compared to other methods like hierarchical clustering or K-means. It also reviews related work applying these clustering algorithms to segment brain MRI images.
1) The document simulates and compares the performance of AODV and DSDV routing protocols in a mobile ad hoc network under three conditions: when users are fixed, when users move towards the base station, and when users move away from the base station.
2) The results show that both protocols have higher packet delivery and lower packet loss when users are either fixed or moving towards the base station, since signal strength is better in those scenarios. Performance degrades when users move away from the base station due to weaker signals.
3) AODV generally has better performance than DSDV, with higher throughput and packet delivery rates observed across the different user mobility conditions.
This document describes the design and implementation of 4-bit QPSK and 256-bit QAM modulation techniques using MATLAB. It compares the two techniques based on SNR, BER, and efficiency. The key steps of implementing each technique in MATLAB are outlined, including generating random bits, modulation, adding noise, and measuring BER. Simulation results show scatter plots and eye diagrams of the modulated signals. A table compares the results, showing that 256-bit QAM provides better performance than 4-bit QPSK. The document concludes that QAM modulation is more effective for digital transmission systems.
The document proposes a hybrid technique using Anisotropic Scale Invariant Feature Transform (A-SIFT) and Robust Ensemble Support Vector Machine (RESVM) to accurately identify faces in images. A-SIFT improves upon traditional SIFT by applying anisotropic scaling to extract richer directional keypoints. Keypoints are processed with RESVM and hypothesis testing to increase accuracy above 95% by repeatedly reprocessing images until the threshold is met. The technique was tested on similar and different facial images and achieved better results than SIFT in retrieval time and reduced keypoints.
This document studies the effects of dielectric superstrate thickness on microstrip patch antenna parameters. Three types of probes-fed patch antennas (rectangular, circular, and square) were designed to operate at 2.4 GHz using Arlondiclad 880 substrate. The antennas were tested with and without an Arlondiclad 880 superstrate of varying thicknesses. It was found that adding a superstrate slightly degraded performance by lowering the resonant frequency and increasing return loss and VSWR, while decreasing bandwidth and gain. Specifically, increasing the superstrate thickness or dielectric constant resulted in greater changes to the antenna parameters.
This document describes a wireless environment monitoring system that utilizes soil energy as a sustainable power source for wireless sensors. The system uses a microbial fuel cell to generate electricity from the microbial activity in soil. Two microbial fuel cells were created using different soil types and various additives to produce different current and voltage outputs. An electronic circuit was designed on a printed circuit board with components like a microcontroller and ZigBee transceiver. Sensors for temperature and humidity were connected to the circuit to monitor the environment wirelessly. The system provides a low-cost way to power remote sensors without needing battery replacement and avoids the high costs of wiring a power source.
1) The document proposes a model for a frequency tunable inverted-F antenna that uses ferrite material.
2) The resonant frequency of the antenna can be significantly shifted from 2.41GHz to 3.15GHz, a 31% shift, by increasing the static magnetic field placed on the ferrite material.
3) Altering the permeability of the ferrite allows tuning of the antenna's resonant frequency without changing the physical dimensions, providing flexibility to operate over a wide frequency range.
This document summarizes a research paper that presents a speech enhancement method using stationary wavelet transform. The method first classifies speech into voiced, unvoiced, and silence regions based on short-time energy. It then applies different thresholding techniques to the wavelet coefficients of each region - modified hard thresholding for voiced speech, semi-soft thresholding for unvoiced speech, and setting coefficients to zero for silence. Experimental results using speech from the TIMIT database corrupted with white Gaussian noise at various SNR levels show improved performance over other popular denoising methods.
This document reviews the design of an energy-optimized wireless sensor node that encrypts data for transmission. It discusses how sensing schemes that group nodes into clusters and transmit aggregated data can reduce energy consumption compared to individual node transmissions. The proposed node design calculates the minimum transmission power needed based on received signal strength and uses a periodic sleep/wake cycle to optimize energy when not sensing or transmitting. It aims to encrypt data at both the node and network level to further optimize energy usage for wireless communication.
This document discusses group consumption modes. It analyzes factors that impact group consumption, including external environmental factors like technological developments enabling new forms of online and offline interactions, as well as internal motivational factors at both the group and individual level. The document then proposes that group consumption modes can be divided into four types based on two dimensions: vertical (group relationship intensity) and horizontal (consumption action period). These four types are instrument-oriented, information-oriented, enjoyment-oriented, and relationship-oriented consumption modes. Finally, the document notes that consumption modes are dynamic and can evolve over time.
The document summarizes a study of different microstrip patch antenna configurations with slotted ground planes. Three antenna designs were proposed and their performance evaluated through simulation: a conventional square patch, an elliptical patch, and a star-shaped patch. All antennas were mounted on an FR4 substrate. The effects of adding different slot patterns to the ground plane on resonance frequency, bandwidth, gain and efficiency were analyzed parametrically. Key findings were that reshaping the patch and adding slots increased bandwidth and shifted resonance frequency. The elliptical and star patches in particular performed better than the conventional design. Three antenna configurations were selected for fabrication and measurement based on the simulations: a conventional patch with a slot under the patch, an elliptical patch with slots
1) The document describes a study conducted to improve call drop rates in a GSM network through RF optimization.
2) Drive testing was performed before and after optimization using TEMS software to record network parameters like RxLevel, RxQuality, and events.
3) Analysis found call drops were occurring due to issues like handover failures between sectors, interference from adjacent channels, and overshooting due to antenna tilt.
4) Corrective actions taken included defining neighbors between sectors, adjusting frequencies to reduce interference, and lowering the mechanical tilt of an antenna.
5) Post-optimization drive testing showed improvements in RxLevel, RxQuality, and a reduction in dropped calls.
This document describes the design of an intelligent autonomous wheeled robot that uses RF transmission for communication. The robot has two modes - automatic mode where it can make its own decisions, and user control mode where a user can control it remotely. It is designed using a microcontroller and can perform tasks like object recognition using computer vision and color detection in MATLAB, as well as wall painting using pneumatic systems. The robot's movement is controlled by DC motors and it uses sensors like ultrasonic sensors and gas sensors to navigate autonomously. RF transmission allows communication between the robot and a remote control unit. The overall aim is to develop a low-cost robotic system for industrial applications like material handling.
This document reviews cryptography techniques to secure the Ad-hoc On-Demand Distance Vector (AODV) routing protocol in mobile ad-hoc networks. It discusses various types of attacks on AODV like impersonation, denial of service, eavesdropping, black hole attacks, wormhole attacks, and Sybil attacks. It then proposes using the RC6 cryptography algorithm to secure AODV by encrypting data packets and detecting and removing malicious nodes launching black hole attacks. Simulation results show that after applying RC6, the packet delivery ratio and throughput of AODV increase while delay decreases, improving the security and performance of the network under attack.
The document describes a proposed modification to the conventional Booth multiplier that aims to increase its speed by applying concepts from Vedic mathematics. Specifically, it utilizes the Urdhva Tiryakbhyam formula to generate all partial products concurrently rather than sequentially. The proposed 8x8 bit multiplier was coded in VHDL, simulated, and found to have a path delay 44.35% lower than a conventional Booth multiplier, demonstrating its potential for higher speed.
This document discusses image deblurring techniques. It begins by introducing image restoration and focusing on image deblurring. It then discusses challenges with image deblurring being an ill-posed problem. It reviews existing approaches to screen image deconvolution including estimating point spread functions and iteratively estimating blur kernels and sharp images. The document also discusses handling spatially variant blur and summarizes the relationship between the proposed method and previous work for different blur types. It proposes using color filters in the aperture to exploit parallax cues for segmentation and blur estimation. Finally, it proposes moving the image sensor circularly during exposure to prevent high frequency attenuation from motion blur.
This document describes modeling an adaptive controller for an aircraft roll control system using PID, fuzzy-PID, and genetic algorithm. It begins by introducing the aircraft roll control system and motivation for developing an adaptive controller to minimize errors from noisy analog sensor signals. It then provides the mathematical model of aircraft roll dynamics and describes modeling the real-time flight control system in MATLAB/Simulink. The document evaluates PID, fuzzy-PID, and PID-GA (genetic algorithm) controllers for aircraft roll control and finds that the PID-GA controller delivers the best performance.
The Rise of Supernetwork Data Intensive ComputingLarry Smarr
Invited Remote Lecture to SC21
The International Conference for High Performance Computing, Networking, Storage, and Analysis
St. Louis, Missouri
November 18, 2021
Are you interested in learning about creating an attractive website? Here it is! Take part in the challenge that will broaden your knowledge about creating cool websites! Don't miss this opportunity, only in "Redesign Challenge"!
Data Protection in a Connected World: Sovereignty and Cyber Securityanupriti
Delve into the critical intersection of data sovereignty and cyber security in this presentation. Explore unconventional cyber threat vectors and strategies to safeguard data integrity and sovereignty in an increasingly interconnected world. Gain insights into emerging threats and proactive defense measures essential for modern digital ecosystems.
For the full video of this presentation, please visit: https://www.edge-ai-vision.com/2024/07/intels-approach-to-operationalizing-ai-in-the-manufacturing-sector-a-presentation-from-intel/
Tara Thimmanaik, AI Systems and Solutions Architect at Intel, presents the “Intel’s Approach to Operationalizing AI in the Manufacturing Sector,” tutorial at the May 2024 Embedded Vision Summit.
AI at the edge is powering a revolution in industrial IoT, from real-time processing and analytics that drive greater efficiency and learning to predictive maintenance. Intel is focused on developing tools and assets to help domain experts operationalize AI-based solutions in their fields of expertise.
In this talk, Thimmanaik explains how Intel’s software platforms simplify labor-intensive data upload, labeling, training, model optimization and retraining tasks. She shows how domain experts can quickly build vision models for a wide range of processes—detecting defective parts on a production line, reducing downtime on the factory floor, automating inventory management and other digitization and automation projects. And she introduces Intel-provided edge computing assets that empower faster localized insights and decisions, improving labor productivity through easy-to-use AI tools that democratize AI.
Transcript: Details of description part II: Describing images in practice - T...BookNet Canada
This presentation explores the practical application of image description techniques. Familiar guidelines will be demonstrated in practice, and descriptions will be developed “live”! If you have learned a lot about the theory of image description techniques but want to feel more confident putting them into practice, this is the presentation for you. There will be useful, actionable information for everyone, whether you are working with authors, colleagues, alone, or leveraging AI as a collaborator.
Link to presentation recording and slides: https://bnctechforum.ca/sessions/details-of-description-part-ii-describing-images-in-practice/
Presented by BookNet Canada on June 25, 2024, with support from the Department of Canadian Heritage.
Hire a private investigator to get cell phone recordsHackersList
Learn what private investigators can legally do to obtain cell phone records and track phones, plus ethical considerations and alternatives for addressing privacy concerns.
AC Atlassian Coimbatore Session Slides( 22/06/2024)apoorva2579
This is the combined Sessions of ACE Atlassian Coimbatore event happened on 22nd June 2024
The session order is as follows:
1.AI and future of help desk by Rajesh Shanmugam
2. Harnessing the power of GenAI for your business by Siddharth
3. Fallacies of GenAI by Raju Kandaswamy
Performance Budgets for the Real World by Tammy EvertsScyllaDB
Performance budgets have been around for more than ten years. Over those years, we’ve learned a lot about what works, what doesn’t, and what we need to improve. In this session, Tammy revisits old assumptions about performance budgets and offers some new best practices. Topics include:
• Understanding performance budgets vs. performance goals
• Aligning budgets with user experience
• Pros and cons of Core Web Vitals
• How to stay on top of your budgets to fight regressions
Coordinate Systems in FME 101 - Webinar SlidesSafe Software
If you’ve ever had to analyze a map or GPS data, chances are you’ve encountered and even worked with coordinate systems. As historical data continually updates through GPS, understanding coordinate systems is increasingly crucial. However, not everyone knows why they exist or how to effectively use them for data-driven insights.
During this webinar, you’ll learn exactly what coordinate systems are and how you can use FME to maintain and transform your data’s coordinate systems in an easy-to-digest way, accurately representing the geographical space that it exists within. During this webinar, you will have the chance to:
- Enhance Your Understanding: Gain a clear overview of what coordinate systems are and their value
- Learn Practical Applications: Why we need datams and projections, plus units between coordinate systems
- Maximize with FME: Understand how FME handles coordinate systems, including a brief summary of the 3 main reprojectors
- Custom Coordinate Systems: Learn how to work with FME and coordinate systems beyond what is natively supported
- Look Ahead: Gain insights into where FME is headed with coordinate systems in the future
Don’t miss the opportunity to improve the value you receive from your coordinate system data, ultimately allowing you to streamline your data analysis and maximize your time. See you there!
An invited talk given by Mark Billinghurst on Research Directions for Cross Reality Interfaces. This was given on July 2nd 2024 as part of the 2024 Summer School on Cross Reality in Hagenberg, Austria (July 1st - 7th)
Video traffic on the Internet is constantly growing; networked multimedia applications consume a predominant share of the available Internet bandwidth. A major technical breakthrough and enabler in multimedia systems research and of industrial networked multimedia services certainly was the HTTP Adaptive Streaming (HAS) technique. This resulted in the standardization of MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH) which, together with HTTP Live Streaming (HLS), is widely used for multimedia delivery in today’s networks. Existing challenges in multimedia systems research deal with the trade-off between (i) the ever-increasing content complexity, (ii) various requirements with respect to time (most importantly, latency), and (iii) quality of experience (QoE). Optimizing towards one aspect usually negatively impacts at least one of the other two aspects if not both. This situation sets the stage for our research work in the ATHENA Christian Doppler (CD) Laboratory (Adaptive Streaming over HTTP and Emerging Networked Multimedia Services; https://athena.itec.aau.at/), jointly funded by public sources and industry. In this talk, we will present selected novel approaches and research results of the first year of the ATHENA CD Lab’s operation. We will highlight HAS-related research on (i) multimedia content provisioning (machine learning for video encoding); (ii) multimedia content delivery (support of edge processing and virtualized network functions for video networking); (iii) multimedia content consumption and end-to-end aspects (player-triggered segment retransmissions to improve video playout quality); and (iv) novel QoE investigations (adaptive point cloud streaming). We will also put the work into the context of international multimedia systems research.
Navigating Post-Quantum Blockchain: Resilient Cryptography in Quantum Threatsanupriti
In the rapidly evolving landscape of blockchain technology, the advent of quantum computing poses unprecedented challenges to traditional cryptographic methods. As quantum computing capabilities advance, the vulnerabilities of current cryptographic standards become increasingly apparent.
This presentation, "Navigating Post-Quantum Blockchain: Resilient Cryptography in Quantum Threats," explores the intersection of blockchain technology and quantum computing. It delves into the urgent need for resilient cryptographic solutions that can withstand the computational power of quantum adversaries.
Key topics covered include:
An overview of quantum computing and its implications for blockchain security.
Current cryptographic standards and their vulnerabilities in the face of quantum threats.
Emerging post-quantum cryptographic algorithms and their applicability to blockchain systems.
Case studies and real-world implications of quantum-resistant blockchain implementations.
Strategies for integrating post-quantum cryptography into existing blockchain frameworks.
Join us as we navigate the complexities of securing blockchain networks in a quantum-enabled future. Gain insights into the latest advancements and best practices for safeguarding data integrity and privacy in the era of quantum threats.
UiPath Community Day Kraków: Devs4Devs ConferenceUiPathCommunity
We are honored to launch and host this event for our UiPath Polish Community, with the help of our partners - Proservartner!
We certainly hope we have managed to spike your interest in the subjects to be presented and the incredible networking opportunities at hand, too!
Check out our proposed agenda below 👇👇
08:30 ☕ Welcome coffee (30')
09:00 Opening note/ Intro to UiPath Community (10')
Cristina Vidu, Global Manager, Marketing Community @UiPath
Dawid Kot, Digital Transformation Lead @Proservartner
09:10 Cloud migration - Proservartner & DOVISTA case study (30')
Marcin Drozdowski, Automation CoE Manager @DOVISTA
Pawel Kamiński, RPA developer @DOVISTA
Mikolaj Zielinski, UiPath MVP, Senior Solutions Engineer @Proservartner
09:40 From bottlenecks to breakthroughs: Citizen Development in action (25')
Pawel Poplawski, Director, Improvement and Automation @McCormick & Company
Michał Cieślak, Senior Manager, Automation Programs @McCormick & Company
10:05 Next-level bots: API integration in UiPath Studio (30')
Mikolaj Zielinski, UiPath MVP, Senior Solutions Engineer @Proservartner
10:35 ☕ Coffee Break (15')
10:50 Document Understanding with my RPA Companion (45')
Ewa Gruszka, Enterprise Sales Specialist, AI & ML @UiPath
11:35 Power up your Robots: GenAI and GPT in REFramework (45')
Krzysztof Karaszewski, Global RPA Product Manager
12:20 🍕 Lunch Break (1hr)
13:20 From Concept to Quality: UiPath Test Suite for AI-powered Knowledge Bots (30')
Kamil Miśko, UiPath MVP, Senior RPA Developer @Zurich Insurance
13:50 Communications Mining - focus on AI capabilities (30')
Thomasz Wierzbicki, Business Analyst @Office Samurai
14:20 Polish MVP panel: Insights on MVP award achievements and career profiling
INDIAN AIR FORCE FIGHTER PLANES LIST.pdfjackson110191
These fighter aircraft have uses outside of traditional combat situations. They are essential in defending India's territorial integrity, averting dangers, and delivering aid to those in need during natural calamities. Additionally, the IAF improves its interoperability and fortifies international military alliances by working together and conducting joint exercises with other air forces.
1. IOSR Journal of Electronics and Communication Engineering (IOSR-JECE)
e-ISSN: 2278-2834,p- ISSN: 2278-8735.Volume 11, Issue 1, Ver.II (Jan. - Feb .2016), PP 05-10
www.iosrjournals.org
DOI: 10.9790/2834-11120510 www.iosrjournals.org 5 | Page
Generalized Channelmodel for Mimo Transceivers Multiplexing
Gain
1
B.Bhargavi Ramya, 2
SK Khajavali
1
M.Tech, Student, 2
Asst. Professor
1,2
Rise Krishna Sai Prakasam Group of Institutions
Abstract:The capability of perfect MIMO channels has a high SNR grade that equals the minimum of the add
active to of transmit and receive masts. This is due to the fact that, unlike base stations, transmits are low-cost
swells that can be simply deployed and, hence, enhances the network agility. The vast majority of works in the
context of relaying grids make the assumption of ideal transceiver hardware. The vast majority of mechanical
contributions in the area of relaying assume ideal transceiver hardware. These deficiencies are conventionally
overlooked in information theoretic studies, but this letter shows that they have a non-negligible and essential
impact on the spectral efficiency in modern deployments with high SNR. Technological advances can condense
transceiver impairments, but then again there is currently an opposite trend towards small low-cost low-power
transceivers where the inherent dirty RF effects are inevitable and the transmission is instead adapted to them.
We prove analytically that such physical MIMO channels have a finite upper capacity limit, for any channel
distribution and SNR.
Keywords: SNR, RF, MIMO, relaying, Transciever
I. Introduction
Wireless communication enjoys considerable attention in the research community. Recent advances are
mainly market driven by the demand for applications with increased data rates. Especially, wireless local area
networks (WLANs), which aim at replacing wired computer network infrastructure with wireless
communication technology, seem to raise a strong demand for further research and development.
Different approaches to boost WLAN data rates have been considered in the past, as reflected in the
amendments of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, First, data rates up
to 11 Mbit/s are supported by IEEE 802.11b compliant equipment. The modulation is direct sequence spread
spectrum-based, which renders wireless channel equalization a complex task in the receiver. Unlike the
conventional point-to-point channels, in a wireless network, the overall throughput of the system is interference
limited.
2. Generalized Channelmodel For Mimo Transceivers Multiplexing Gain
DOI: 10.9790/2834-11120510 www.iosrjournals.org 6 | Page
That is, boosting up the transmitted power of a user cannot efficiently increase the spectrum efficiency
of the network, since strong signals transmitted by one user acts as strong interference on other users. Therefore,
it is of interest to develop approaches to increase the spectrum efficiency without increasing the transmitted
power. With the introduction of orthogonal frequency-division multiplexing (OFDM) [1] techniques in the
popular IEEE 802.11a and IEEE 802.11g standards, data rates up to 54 Mbits/s in a bandwidth of 20 MHz can
be realized with low complexity channel equalization. Channel bonding, i.e., expanding the bandwidth from 20
MHz to 40 MHz, doubles the data throughput in some systems.
OFDM has been employed in other standards as well due to its suitability for transmission over
wireless links that exhibit frequency selectivity. These include standards for metropolitan area networks such as
the IEEE 802.16 (WiMAX) standard. Even for broadcast systems, OFDM is becoming increasingly important.
This manifests itself through the introduction of digital radio mondiale and digital audio broadcast in the short-
wave bands and high-frequency bands, respectively. For video broadcasting, OFDM with advanced data
compression techniques is also set to replace legacy analog transmission schemes.
The capacity of ideal MIMO channels has a high SNR slope that equals the minimum of the number of
transmit and receive antennas. This letter analyzes if this result holds when there are distortions from physical
transceiver impairments. We prove analytically that such physical MIMO channels have a finite upper capacity
limit, for any channel distribution and SNR. The high-SNR slope thus collapses to zero. This appears
discouraging, but we prove the encouraging result that the relative capacity gain of employing MIMO is at least
as large as with ideal transceivers.
This work analyzes the generalized MIMO channel with transceiver impairments. We show that the
capacity has a finite high-SNR limit for any channel distribution. The multiplexing gain is thus zero, which is
fundamentally different from the ideal case in (detailed above). Similar single antenna results are give. The
practical MIMO gain— the relative capacity increase over single-antenna channels—is however shown to be at
least as large as with ideal transceivers.
II. Methodology
This section outlines the notation used in this thesis. An exhaustive list of all operators and variables is
given in Appendix A. A matrix is denoted by a bold uppercase letter. The entry of matrix A in the rth row and cth
column is denoted by ar , c. The cth column of matrix A is denoted by ac. Lowercase bold letters denote vectors.
Therth entry of vector a is denoted by ar.
To describe MIMO-OFDM systems in vector notation, three dimensions are required. This can be
introduced making use of brackets[·]. Therefore, A[m] denotes the mth matrix of a collection of M matrices. The
c, rth element of the mth matrix is denoted by ar, c[m]. This extra dimension describes usually the time or
frequency index. ar, c[·] denotes aM×1column vector containing all entries ar, c[m] wherem=0,1,...,M−1. See
Figure 2.1 for an illustration of the notation.
Brackets may also be used to access individual entries of a vector; thus, the rth entry of a vector a is
denoted as a[r]=ar. Occasionally, the index exceeds the defined length of a vector. We assume all vectors to be
virtually expanded with zeros, thus returning() in these cases. The symbols w and k denote indices in the
frequency domain and time domain, respectively. Constants, operators, and identifiers of variables are always
written in upright font, for example, Ahs denotes the Hermitian transposition of a matrix A with label s.
In this section, a frame-based MIMO-OFDM system model is introduced. The structure of this MIMO
Model is organized in order to be compatible with the IEEE 802.11 system description. Spatialmultiplexing is
employed, where multiple, independent streams are transmitted in parallel in the same frequency band at the
same time. The data is transmitted in frames. This allows multiple users to access the same physical resources
easily by means of time division multiple access (TDMA). The MIMO system under consideration employs MT
antennas at the transmit terminal andMRantennas at the receive terminal as outlined in Figure 2.2 and Figure
2.1, respectively. For a spatial multiplexing system to function efficiently, we impose that the number of receive
antennasMRalways exceeds or equals the number of transmit antennas MT.
III. Channel Capacity
The Shannon capacity of a time-invariant channel is defined as the maximum mutual information
between the channel input and output. This is the maximum data rate that can be transmitted over the channel
with arbitrarily small error probability. When the CSI is perfectly known at both the transmitter and the receiver,
the transmitter can adapt its transmission strategy relative to the instantaneous channel state. If the channel is
time variant, the ergodic capacity is the maximum mutual information averaged over all channel states. The
ergodic capacity is typically achieved using an adaptive transmission policy where the power and data rate vary
relative to the channel state variations. In a multiple user scenario, MU MIMO allows the reuse of time and
frequency resources. Due to the scattering in different scenarios, the users’ wavefronts may have large angle
spreads and random signatures. Therefore, even users that are well separated in angle may have potentially
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overlapping subspaces spanned by left singular vectors of their channel matrices. Separability of their subspaces
is much more difficult to achieve.
In a single-user MIMO system the link is point-to-point with a defined capacity. In a multi-user MIMO
system, the link is a multiple access channel on the uplink and broadcast channel on the downlink. The
achievable rates are characterized in this case in terms of a sum rate region. SU MIMO suffers only a small
penalty in information rate without CSI at the transmitter. MU MIMO has a much larger penalty on the
downlink. In a SU MIMO system, precoding at the transmitter and decoding at the receiver can be done with
full cooperation between the collocated antennas. In a MU MIMO system, the antennas can cooperate at the
base station for precoding on the downlink and for decoding on the uplink. However, the users cannot cooperate
in decoding on the downlink or during the precoding on the uplink. In a MU MIMO system, cooperation
between the users may be possible in terms of power rates assigned to the users. In a SU MIMO system, the
information rate is identical on the uplink and downlink for the same transmit power if the channel is known at
the transmitter and the receiver.
IV. Tx-Rx Impairments
MIMO wireless communication systems have attracted considerable attention over the past decades
due to their ability to enhance the channel capacity and transmission reliability. Telatar and Foschini have
respectively and that there is a linear growth in channel capacity by increasing the number of transmit and
receive antennas, without requiring additional transmit power or bandwidth. Although numerous publications
have appeared in this field, the vast majority assumes ideal RF hardware.
Fig 1.0.: Block diagram of the generalized MIMO channel considered in this letter. Unlike the classical
channel model, the transmitter distortion generated by physical transceiver implementations is included
in the model.
Physical radio-frequency (RF) transceivers suffer from amplifier non-linearities, IQ-imbalance, phase
noise, quantization noise, carrier-frequency and sampling-rate jitter/offsets, etc. These impairments are
conventionally overlooked in information theoretic studies, but this letter shows that they have a non-negligible
and fundamental impact on the spectral efficiency in modern deployments with high SNR. This letter analyzes
the generalized MIMO channel with transceiver impairments from [7]. We show that the capacity has a finite
high-SNR limit for any channel distribution. The multiplexing gain is thus zero, which is fundamentally
different from the ideal case in [1] (detailed above). Similar single antenna results are given in [5]. The practical
MIMO gain— the relative capacity increase over single-antenna channels—is however shown to be at least as
large as with ideal transceivers.
However, this assumption is quite unrealistic in practice. More specifically, RF impairments, such as
I/Q imbalance HPA nonlinearities and oscillator PN are known to have a deleterious impact on the performance
of practical MIMO systems. Even though one can resort to calibration schemes at the transmitter, or
compensation algorithms at the receiver to partially mitigate these impairments [9], there still remains certain
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amount of distortion unaccounted for. The reasons for such residual transceiver impairments are, for example,
inaccurate models which are used to characterize the impairments’ behavior, imperfect parameters estimation
errors due to thermal noise, and unsophisticated compensation algorithms with limited capabilities.
In this context, very few publications have studied the impact of residual transceiver impairments. For
example provided experimental results to model the statistical behavior of residual hardware impairments.
Moreover, they also investigated the impact of transmitter impairments on several existing MIMO detection
algorithms (e.g., zero-forcing detection, maximum-likelihood detection, and max-log a posteriori probability
detection).
In real-world systems, signals are affected by non-idealities and imperfections. In the case of the test
bed, the RF-chain in the transmit and receive-path is especially vulnerable to impairments. In this chapter, the
main impairments in the transmit-path of the test bed are identified and measured. The EVM is used to
determine the overall performance of the transmit chain. Then, the system model introduced is changed such
that impairments in the transmit-path are also considered. The impact of impairments in the transmit-path on
different MIMO detection algorithms is illustrated by simulations and measurements carried out on the offline-
test bed. And last but not least, performance measurements of the real-time test bed are shown.
V. Outputs
Technological advances can reduce transceiver impairments,but there is currently an opposite trend
towards small low-costlow-power transceivers where the inherent dirty RF effects areinevitable and the
transmission is instead adapted to them.
Fig.2.0 Average capacity of a 4x4 MIMO channel over different deterministic channel realizations, different
levels of transceiver impairments, and α = 1.
Fig.2.1 Capacity of a MIMO channel with Nr = 4 and impairments with K= 0.05. We consider different Nt ,
channel distributions, and α-values
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Fig.2.2 Finite-SNR multiplexing gain for an uncorrelated Rayleigh fading channel with Nr = 4 and Nt ≥ 4.
Fig.2.3Average finite-SNR multiplexing gain of deterministic channels (generated with independent CN (0, 1)-
entries) with Nr = 4 and Nt 4.
VI. Conclusion
Due to the lack of a fundamental metric of the performance, previous research on multiple antennas
channels, especially the design of the coding schemes, is split into two different branches, focusing either on
extracting the maximal diversity gain or the maximum spatial multiplexing gain. The purpose of this dissertation
is to provide a unified view of the problem, by drawing a picture that connects these two types of gains. The
main contribution of this dissertation is summarized as follows. We propose the new point-of-view that given a
multiple antenna system both the diversity gain and the multiplexing gain can be simultaneously achieved, but
there is a fundamental tradeoff between how much of each type of gain any coding scheme can achieve.
We give a concrete definition of the diversity gain and the spatial multiplexing gain for the multiple
antenna channels, and a complete concept of the asymptotic analysis at high SNR. For the coherent channel
model, we give a simple closed form solution of the optimal tradeoff curve, as well as a geometric interpretation
that helps to understand the typical way to make detection errors in such a channel. The ability of ideal MIMO
channels has a high-SNR slope that equals the minimum of the number of transceiver antennas.
This work evaluates if this result holds when there are distortions from physical transceiver limitations.
We prove analytically that such physical MIMO channels have a finite upper capacity limit, for any channel
distribution and SNR. The high-SNR slope thus collapses to zero. This appears discouraging, but we prove the
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encouraging result that the relative capacity gain of employing MIMO is at least as large as with ideal
transceivers. The entire results will be shown in MATLAB platform effectively.
The approach provides valuable insights to the resource in MIMO systems and understanding of the
traditional techniques such as the union bound. We propose to use the tradeoff performance as a comprehensive
performance metric. We use this metric to analysis several well-known schemes, to understand their limit and
propose improvement.
We computed the high SNR channel capacity of the non-coherent channel, generalized the notion of
degrees of freedom. We used a geometric approach that is useful in general problems. We compute the optimal
tradeoff curve for the non-coherent channel. We evaluate the performance of a pilot-based scheme, and show
that it is optimal both in terms of achieving the maximum number of d.o.f, and achieving the entire optimal
tradeoff curve. This result provides theoretical support to apply the results for the coherent channel in the non-
coherent case. We also give an intuitive discussion to understand the training schemes and the unitary space-
time codes.
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