This document discusses using implicit training via the MUSIC algorithm to approximate the capacity of an MMSE equalizer in fading channels without full channel state information. It shows that for a slow fading channel, the MUSIC algorithm can approach the explicit MMSE training capacity of 5 bits/Hz within 1 dB. For a faster fading channel, implicit training via MUSIC can realize up to a 2 dB improvement in capacity compared to explicit training, achieving over 4 bits/Hz capacity. The document outlines the MMSE equalizer, MUSIC algorithm, and a proposed method to use MUSIC to implicitly train an MMSE equalizer without explicit training symbols.
A COMPARATIVE PERFORMANCE STUDY OF OFDM SYSTEM WITH THE IMPLEMENTATION OF COM...ijcsa
This paper presents a comparative performance analysis of wireless orthogonal frequency division multiplexing (OFDM) system with the implementation of comb type pilot-based channel estimation algorithm over frequency selective multi-path fading channels. The Minimum Mean Square Error (MMSE) method is used for the estimation of channel at pilot frequencies. For the estimation of channel at data frequencies different interpolation techniques such as low-pass, linear, and second order interpolation are employed. The OFDM system simulation has been carried out with Matlab and the performance is analyzed in terms of bit error rate (BER) for various signal mapping (BPSK, QPSK, 4QAM, 16QAM, and 64QAM) and channel (Rayleigh and Rician) conditions. The impact of selecting number of channel taps on the BER performance is also investigated.
A novel delay dictionary design for compressive sensing-based time varying ch...TELKOMNIKA JOURNAL
Compressive sensing (CS) is a new attractive technique adopted for Linear Time Varying channel estimation. orthogonal frequency division multiplexing (OFDM) was proposed to be used in 4G and 5G which supports high data rate requirements. Different pilot aided channel estimation techniques were proposed to better track the channel conditions, which consumes bandwidth, thus, considerable data rate reduced. In order to estimate the channel with minimum number of pilots, compressive sensing CS was proposed to efficiently estimate the channel variations. In this paper, a novel delay dictionary-based CS was designed and simulated to estimate the linear time varying (LTV) channel. The proposed dictionary shows the suitability of estimating the channel impulse response (CIR) with low to moderate Doppler frequency shifts with acceptable bit error rate (BER) performance.
This document studies MIMO channel capacity using channel models from the IST METRA European project. It finds that MIMO systems can increase channel capacity linearly with the minimum number of antennas by exploiting multipath and spatial diversity. The document analyzes capacity for correlated and uncorrelated channel models. It shows that spatial correlation decreases capacity gains and the rate of capacity increase with higher SNR. Keeping the number of receivers constant provides higher capacity than varying the number of transmitters.
Swarm Intelligence Technique ACO and Traveling Salesman ProblemIRJET Journal
The document discusses the ant colony optimization (ACO) algorithm, a swarm intelligence technique inspired by ant behavior, and its application to the traveling salesman problem (TSP). ACO mimics how ants deposit and follow pheromone trails to probabilistically determine paths, and it has been shown to find good solutions to TSP. The paper also reviews the ACO algorithm and describes how it can be applied to find the shortest tour between cities in TSP.
Singular Value Decomposition: Principles and Applications in Multiple Input M...IJCNCJournal
The authors discuss the importance of using the singular value decomposition (SVD) in computing the capacity of multiple input multiple output (MIMO) and in estimation the channel gain from the transmitter to the receiver. Examples that show how the SVD simplifies computing the MIMO channel capacity are discussed. Numerical results that show what factors determine the performance of using SVD in channel
estimation are also discussed.
Optimal channel switching over gaussian channels under average power and cost...Deepshika Reddy
This document describes proposed methods for optimally switching between channels under average power and cost constraints. It first considers generic cost values and characterizes the optimal strategy. It then relates channel cost to noise power using logarithmic cost functions to obtain specific results. The proposed methods are: 1) analyze switching between two channels, 2) among three channels, or 3) a single channel. Key findings include showing optimal strategies utilize maximum power and cost, and involve at most three channels. Relations between optimal power levels for two-channel switching are also derived.
Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless ...graphhoc
The document discusses performance comparisons of different receiver structures for high data rate ultra wideband communication systems. It analyzes Rake, MMSE, and Rake-MMSE receivers using MATLAB simulations on IEEE 802.15.3a channel models. The Rake-MMSE receiver combines advantages of Rake fingers and equalization to combat inter-symbol interference. Simulation results show the Rake-MMSE receiver achieves a lower bit error rate than Rake or MMSE receivers alone. The number of Rake fingers improves performance at low-medium SNR, while more equalizer taps help at high SNR.
This document discusses using implicit training via the MUSIC algorithm to approximate the capacity of an MMSE equalizer in fading channels without full channel state information. It shows that for a slow fading channel, the MUSIC algorithm can approach the explicit MMSE training capacity of 5 bits/Hz within 1 dB. For a faster fading channel, implicit training via MUSIC can realize up to a 2 dB improvement in capacity compared to explicit training, achieving over 4 bits/Hz capacity. The document outlines the MMSE equalizer, MUSIC algorithm, and a proposed method to use MUSIC to implicitly train an MMSE equalizer without explicit training symbols.
A COMPARATIVE PERFORMANCE STUDY OF OFDM SYSTEM WITH THE IMPLEMENTATION OF COM...ijcsa
This paper presents a comparative performance analysis of wireless orthogonal frequency division multiplexing (OFDM) system with the implementation of comb type pilot-based channel estimation algorithm over frequency selective multi-path fading channels. The Minimum Mean Square Error (MMSE) method is used for the estimation of channel at pilot frequencies. For the estimation of channel at data frequencies different interpolation techniques such as low-pass, linear, and second order interpolation are employed. The OFDM system simulation has been carried out with Matlab and the performance is analyzed in terms of bit error rate (BER) for various signal mapping (BPSK, QPSK, 4QAM, 16QAM, and 64QAM) and channel (Rayleigh and Rician) conditions. The impact of selecting number of channel taps on the BER performance is also investigated.
A novel delay dictionary design for compressive sensing-based time varying ch...TELKOMNIKA JOURNAL
Compressive sensing (CS) is a new attractive technique adopted for Linear Time Varying channel estimation. orthogonal frequency division multiplexing (OFDM) was proposed to be used in 4G and 5G which supports high data rate requirements. Different pilot aided channel estimation techniques were proposed to better track the channel conditions, which consumes bandwidth, thus, considerable data rate reduced. In order to estimate the channel with minimum number of pilots, compressive sensing CS was proposed to efficiently estimate the channel variations. In this paper, a novel delay dictionary-based CS was designed and simulated to estimate the linear time varying (LTV) channel. The proposed dictionary shows the suitability of estimating the channel impulse response (CIR) with low to moderate Doppler frequency shifts with acceptable bit error rate (BER) performance.
This document studies MIMO channel capacity using channel models from the IST METRA European project. It finds that MIMO systems can increase channel capacity linearly with the minimum number of antennas by exploiting multipath and spatial diversity. The document analyzes capacity for correlated and uncorrelated channel models. It shows that spatial correlation decreases capacity gains and the rate of capacity increase with higher SNR. Keeping the number of receivers constant provides higher capacity than varying the number of transmitters.
Swarm Intelligence Technique ACO and Traveling Salesman ProblemIRJET Journal
The document discusses the ant colony optimization (ACO) algorithm, a swarm intelligence technique inspired by ant behavior, and its application to the traveling salesman problem (TSP). ACO mimics how ants deposit and follow pheromone trails to probabilistically determine paths, and it has been shown to find good solutions to TSP. The paper also reviews the ACO algorithm and describes how it can be applied to find the shortest tour between cities in TSP.
Singular Value Decomposition: Principles and Applications in Multiple Input M...IJCNCJournal
The authors discuss the importance of using the singular value decomposition (SVD) in computing the capacity of multiple input multiple output (MIMO) and in estimation the channel gain from the transmitter to the receiver. Examples that show how the SVD simplifies computing the MIMO channel capacity are discussed. Numerical results that show what factors determine the performance of using SVD in channel
estimation are also discussed.
Optimal channel switching over gaussian channels under average power and cost...Deepshika Reddy
This document describes proposed methods for optimally switching between channels under average power and cost constraints. It first considers generic cost values and characterizes the optimal strategy. It then relates channel cost to noise power using logarithmic cost functions to obtain specific results. The proposed methods are: 1) analyze switching between two channels, 2) among three channels, or 3) a single channel. Key findings include showing optimal strategies utilize maximum power and cost, and involve at most three channels. Relations between optimal power levels for two-channel switching are also derived.
Performance Analysis of Ultra Wideband Receivers for High Data Rate Wireless ...graphhoc
The document discusses performance comparisons of different receiver structures for high data rate ultra wideband communication systems. It analyzes Rake, MMSE, and Rake-MMSE receivers using MATLAB simulations on IEEE 802.15.3a channel models. The Rake-MMSE receiver combines advantages of Rake fingers and equalization to combat inter-symbol interference. Simulation results show the Rake-MMSE receiver achieves a lower bit error rate than Rake or MMSE receivers alone. The number of Rake fingers improves performance at low-medium SNR, while more equalizer taps help at high SNR.
This document proposes a discrete wavelet transform (DWT)-based channel estimation method for MIMO-OFDM systems. It describes the transmitter and receiver structures of a wavelet-based OFDM system with multiple antennas. At the transmitter, data is modulated using inverse DWT and transmitted over frequency-selective channels. At the receiver, received signals are processed using DWT to estimate the channel. Least squares and minimum mean squared error estimation techniques are discussed. Simulation results show the DWT-based system achieves better bit error rate performance than conventional FFT-based OFDM.
An improved dft based channel estimationsakru naik
This document proposes an improved DFT-based channel estimation method for MIMO-OFDM systems. The conventional DFT method causes energy leakage in non-sample-spaced multipath channels. The improved method extends the LS estimate using symmetry, calculates the changing rate of leakage energy, and selects useful paths based on this rate to reduce leakage energy. Simulation results show the improved method reduces leakage energy more efficiently and provides better channel estimation performance than LS and conventional DFT algorithms.
Design and Implementation of Efficient Analysis and Synthesis QMF Bank for Mu...TELKOMNIKA JOURNAL
The present section deals with a new type of technique for designing an efficient two channel Quadrature Mirror Filter Bank with constant phase in frequency. For achieving the Perfect Reconstruction Condition in Filter bank, an attempt has been made to design the low pass prototype filter with its impulse response and frequency response in three regions namely pass band, stop band and transition band region. With the error in terms of Reconstruction and the attenuation in the stop band as seen in the prototype filter response, one can evaluate the performance of the introduced filter with the help of filter coefficients generated in the design examples that affects the quality of filter bank design under the constraints of Near Perfect Reconstruction Conditions.
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.
In this paper, we analyzed a numerical evaluation of the performance of MIMO radio systems in the LTE network environment. Downlink physical layer of the OFDM-MIMO based radio interface is considered for system model and a theoretical analysis of the bit error rate of the two space-time codes (SFBC 2×1 and FSTD 4×2 codes are adopted by the LTE norm as a function of the signal to noise ratio. Analytical expressions are given for transmission over a Rayleigh channel without spatial correlation which is then compared with Monte-Carlo simulations. Further evaluated channel capacity and simulation results show throughput almost reaches to the capacity limit.
Blind channel estimation for mimo ofdm systemstrungquang0207
This document presents a blind channel estimation technique for MIMO-OFDM systems. It generalizes existing subspace-based methods for single-input single-output OFDM systems to operate with multiple transmit and receive antennas. The proposed method establishes conditions for channel identifiability. It obtains accurate channel estimates using a small number of OFDM symbols and is insensitive to overestimates of the true channel order. The method can work with no or insufficient cyclic prefix if virtual carriers are present, potentially increasing channel utilization. Simulation results show the mean-square error performance of the proposed method.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
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.
Localized Algorithm for Channel Assignment in Cognitive Radio NetworksIJERA Editor
Cognitive Radio has been emerged as a revolutionary solution to migrate the current shortage of spectrum
allocation in wireless networks. In this paper, an improved localized channel allocation algorithm based on
channel weight is proposed. A factor of channel stability is introduced based on link environment, which
efficiently assigns the best channels to the links. Based on the framework, a conflict resolution strategy is used to
make the scheme adaptable to different network conditions. Calculations indicate that this algorithm can reduce
the conflicts, increase the delivery rate and link assignment rate compared with the basic channel assignment
algorithm.
A COMPARISON BETWEEN SWARM INTELLIGENCE ALGORITHMS FOR ROUTING PROBLEMSecij
Travelling salesman problem (TSP) is a most popular combinatorial routing problem, belongs to the class of NP-hard problems. Many approacheshave been proposed for TSP.Among them, swarm intelligence (SI) algorithms can effectively achieve optimal tours with the minimum lengths and attempt to avoid trapping in local minima points. The transcendence of each SI is depended on the nature of the problem. In our studies, there has been yet no any article, which had compared the performance of SI algorithms for TSP perfectly. In this paper,four common SI algorithms are used to solve TSP, in order to compare the performance of SI algorithms for the TSP problem. These algorithms include genetic algorithm, particle swarm optimization, ant colony optimization, and artificial bee colony. For each SI, the various parameters and operators were tested, and the best values were selected for it. Experiments oversome benchmarks fromTSPLIBshow that
artificial bee colony algorithm is the best one among the fourSI-basedmethods to solverouting problems like TSP.
Performance Analysis of PAPR Reduction in MIMO-OFDMIJARBEST JOURNAL
Authors: Jayaraman.G1, VeeraKumar K2, Selvakani.S3
Abstract— In communication system, it is aimed to provide highest possible
transmission rate at the lowest possible power and with the least possible noise. MIMOOFDM
has been chosen for high data rate communications and widely deployed in many
wireless communication standards. The major drawback in OFDM signal transmission is
high PAPR. In previous, use clipping technique to tackle this problem. In this paper, use
EM-GAMP algorithm to reduce PAPR in considerable amount.
Adaptive Channel Equalization for Nonlinear Channels using Signed Regressor F...IDES Editor
Wireless communication systems are affected by
inter-symbol interference (ISI), co-channel interference in
the presence of additive white Gaussian noise. ISI is primarily
due to the distortion caused by frequency and time selectivity
of the fading channel and it causes performance degradation.
Equalization techniques are used to mitigate the effect of ISI
and noise for better demodulation. This paper presents a novel
technique for channel equalization. Here a Signed Regressor
adaptive algorithm based on FLANN (Functional Link Artificial
Neural Network) has been developed for nonlinear channel
equalization along with the analysis of MSE and BER. The
results are compared with the conventional adaptive LMS
algorithm based FLANN model. The Signed Regressor FLANN
shows better performance as compared to LMS based FLANN.
The equalizer presented shows considerable performance
compared to the other adaptive structure for both the linear
and non-linear models in terms of convergence rate, MSE
and BER over a wide range.
Multi-Level Ant Colony Algorithm for Optimal Placement of Capacitors on a dis...rannaluru
This document describes a multi-level ant colony algorithm for optimally placing capacitors in distribution systems. The algorithm uses two separate pheromone tables to make a two-stage decision on capacitor placement - first selecting optimal bus locations, then selecting capacitor ratings. Test results on a 30-bus system show the algorithm finds lower cost solutions than previous methods, requiring fewer capacitors.
Adjusting the flow in crucial areas can maximize the overall throughput of traffic along a stretch of road. This is of particular interest in regions of high traffic density, which may be caused by high volume peak time traffic, accidents or closure of one or more lanes of the road.
Implementation of channel estimation algorithms in ofdm for 64 subcarriersIAEME Publication
The document discusses channel estimation algorithms in OFDM systems with 64 subcarriers. It compares the performance of least squares (LS), linear minimum mean square error (LMMSE), and modified MMSE channel estimation algorithms for different modulation schemes including PSK and QAM. Simulation results show that the modified MMMSE algorithm, which considers a reduced channel correlation matrix, achieves a lower symbol error rate than LS and LMMSE, especially at high SNRs, with reduced computational complexity compared to LMMSE.
Orthogonal Frequency Division Multiplexing (OFDM) is of great interest for the development of
the fifth-generation technology. It is the cornerstone of Multiple-input multiple-output (MIMO) systems.
Even though inter carrier interference (ICI) and inter symbol interference (ISI) have been processed for
the fourth-generation standards, they still present a huge problem for the fifth-generation standards. This
paper explores the tradeoff between the length of the cyclic prefix and the performances of the OFDM
system. It also studies the effect of carrier frequency offset (CFO) on OFDM systems. A blind frequency
offset estimator that uses the correlations between the remodulated sequence in the receiver side and
the conventional received symbol is presented and a closed form solution is derived. The proposed
estimator is derived under short interval when the correlation is high, so it has low computational
complexity. Lin and Beek’s estimators are used for comparison. Simulations demonstrate the effectiveness
of the proposed estimator under Rayleigh fading channel.
EVALUATION OF MIMO SYSTEM CAPACITY OVER RAYLEIGH FADING CHANNELIJCSES Journal
High transmission data rate, spectral efficiency and reliability are essential for future wireless
communications systems. MIMO (multi-input multi-output) diversity technique is a band width efficient
system achieving high data transmission which eventually establishing a high capacity communication
system. Without needing to increase the transmitted power or the channel bandwidth, gain in capacity can
be considerably improved by varying the number of antennas on both sides. Correlated and uncorrelated
channels MIMO system was considered in this paper for different number of antennas and different SNR
over Rayleigh fading channel. At the transmitter both CSI(channel state information) technique and Water
filling power allocation principle was also considered in this paper.
This document summarizes a B.Tech project thesis defense on distributed learning and adaptation in cognitive radio. The project aimed to develop a decentralized learning system to map secondary users to idle primary network channels without collision. The methodology used a novel Distributed Learning and Adaptive algorithm (DALA) policy based on stochastic learning and an Upper Confidence Bound algorithm. Simulation results showed the DALA policy converged channel selection probabilities and secondary users were assigned different channels. Mini-batch stochastic learning improved performance over DALA by reducing regret. Thresholding channel probabilities provided faster convergence. Future work may include variable step sizes, dynamic channel availability, and new ranking schemes.
Projected Barzilai-Borwein Methods Applied to Distributed Compressive Spectru...Polytechnique Montreal
Cognitive radio allows unlicensed (cognitive) users to use licensed frequency bands by exploiting spectrum sensing techniques to detect whether or not the licensed (primary) users are present. In this paper, we present a compressed sensing applied to spectrum-occupancy detection in wide-band applications. The collected analog signals from each cognitive radio (CR) receiver at a fusion center are transformed to discrete-time signals by using analog-to-information converter (AIC) and then employed to calculate the autocorrelation. For signal reconstruction, we exploit a novel approach to solve the optimization problem consisting of minimizing both a quadratic (l2) error term and an l1-regularization term. In specific, we propose the Basic gradient projection (GP) and projected Barzilai-Borwein (PBB) algorithm to offer a better performance in terms of the mean squared error of the power spectrum density estimate and the detection probability of licensed signal occupancy.
These slides deal with the basic problem of channel equalization and exposes the issue related to it and shows how it can be balanced by the usage of effective and robust algorithms.
This document proposes a discrete wavelet transform (DWT)-based channel estimation method for MIMO-OFDM systems. It describes the transmitter and receiver structures of a wavelet-based OFDM system with multiple antennas. At the transmitter, data is modulated using inverse DWT and transmitted over frequency-selective channels. At the receiver, received signals are processed using DWT to estimate the channel. Least squares and minimum mean squared error estimation techniques are discussed. Simulation results show the DWT-based system achieves better bit error rate performance than conventional FFT-based OFDM.
An improved dft based channel estimationsakru naik
This document proposes an improved DFT-based channel estimation method for MIMO-OFDM systems. The conventional DFT method causes energy leakage in non-sample-spaced multipath channels. The improved method extends the LS estimate using symmetry, calculates the changing rate of leakage energy, and selects useful paths based on this rate to reduce leakage energy. Simulation results show the improved method reduces leakage energy more efficiently and provides better channel estimation performance than LS and conventional DFT algorithms.
Design and Implementation of Efficient Analysis and Synthesis QMF Bank for Mu...TELKOMNIKA JOURNAL
The present section deals with a new type of technique for designing an efficient two channel Quadrature Mirror Filter Bank with constant phase in frequency. For achieving the Perfect Reconstruction Condition in Filter bank, an attempt has been made to design the low pass prototype filter with its impulse response and frequency response in three regions namely pass band, stop band and transition band region. With the error in terms of Reconstruction and the attenuation in the stop band as seen in the prototype filter response, one can evaluate the performance of the introduced filter with the help of filter coefficients generated in the design examples that affects the quality of filter bank design under the constraints of Near Perfect Reconstruction Conditions.
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.
In this paper, we analyzed a numerical evaluation of the performance of MIMO radio systems in the LTE network environment. Downlink physical layer of the OFDM-MIMO based radio interface is considered for system model and a theoretical analysis of the bit error rate of the two space-time codes (SFBC 2×1 and FSTD 4×2 codes are adopted by the LTE norm as a function of the signal to noise ratio. Analytical expressions are given for transmission over a Rayleigh channel without spatial correlation which is then compared with Monte-Carlo simulations. Further evaluated channel capacity and simulation results show throughput almost reaches to the capacity limit.
Blind channel estimation for mimo ofdm systemstrungquang0207
This document presents a blind channel estimation technique for MIMO-OFDM systems. It generalizes existing subspace-based methods for single-input single-output OFDM systems to operate with multiple transmit and receive antennas. The proposed method establishes conditions for channel identifiability. It obtains accurate channel estimates using a small number of OFDM symbols and is insensitive to overestimates of the true channel order. The method can work with no or insufficient cyclic prefix if virtual carriers are present, potentially increasing channel utilization. Simulation results show the mean-square error performance of the proposed method.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
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.
Localized Algorithm for Channel Assignment in Cognitive Radio NetworksIJERA Editor
Cognitive Radio has been emerged as a revolutionary solution to migrate the current shortage of spectrum
allocation in wireless networks. In this paper, an improved localized channel allocation algorithm based on
channel weight is proposed. A factor of channel stability is introduced based on link environment, which
efficiently assigns the best channels to the links. Based on the framework, a conflict resolution strategy is used to
make the scheme adaptable to different network conditions. Calculations indicate that this algorithm can reduce
the conflicts, increase the delivery rate and link assignment rate compared with the basic channel assignment
algorithm.
A COMPARISON BETWEEN SWARM INTELLIGENCE ALGORITHMS FOR ROUTING PROBLEMSecij
Travelling salesman problem (TSP) is a most popular combinatorial routing problem, belongs to the class of NP-hard problems. Many approacheshave been proposed for TSP.Among them, swarm intelligence (SI) algorithms can effectively achieve optimal tours with the minimum lengths and attempt to avoid trapping in local minima points. The transcendence of each SI is depended on the nature of the problem. In our studies, there has been yet no any article, which had compared the performance of SI algorithms for TSP perfectly. In this paper,four common SI algorithms are used to solve TSP, in order to compare the performance of SI algorithms for the TSP problem. These algorithms include genetic algorithm, particle swarm optimization, ant colony optimization, and artificial bee colony. For each SI, the various parameters and operators were tested, and the best values were selected for it. Experiments oversome benchmarks fromTSPLIBshow that
artificial bee colony algorithm is the best one among the fourSI-basedmethods to solverouting problems like TSP.
Performance Analysis of PAPR Reduction in MIMO-OFDMIJARBEST JOURNAL
Authors: Jayaraman.G1, VeeraKumar K2, Selvakani.S3
Abstract— In communication system, it is aimed to provide highest possible
transmission rate at the lowest possible power and with the least possible noise. MIMOOFDM
has been chosen for high data rate communications and widely deployed in many
wireless communication standards. The major drawback in OFDM signal transmission is
high PAPR. In previous, use clipping technique to tackle this problem. In this paper, use
EM-GAMP algorithm to reduce PAPR in considerable amount.
Adaptive Channel Equalization for Nonlinear Channels using Signed Regressor F...IDES Editor
Wireless communication systems are affected by
inter-symbol interference (ISI), co-channel interference in
the presence of additive white Gaussian noise. ISI is primarily
due to the distortion caused by frequency and time selectivity
of the fading channel and it causes performance degradation.
Equalization techniques are used to mitigate the effect of ISI
and noise for better demodulation. This paper presents a novel
technique for channel equalization. Here a Signed Regressor
adaptive algorithm based on FLANN (Functional Link Artificial
Neural Network) has been developed for nonlinear channel
equalization along with the analysis of MSE and BER. The
results are compared with the conventional adaptive LMS
algorithm based FLANN model. The Signed Regressor FLANN
shows better performance as compared to LMS based FLANN.
The equalizer presented shows considerable performance
compared to the other adaptive structure for both the linear
and non-linear models in terms of convergence rate, MSE
and BER over a wide range.
Multi-Level Ant Colony Algorithm for Optimal Placement of Capacitors on a dis...rannaluru
This document describes a multi-level ant colony algorithm for optimally placing capacitors in distribution systems. The algorithm uses two separate pheromone tables to make a two-stage decision on capacitor placement - first selecting optimal bus locations, then selecting capacitor ratings. Test results on a 30-bus system show the algorithm finds lower cost solutions than previous methods, requiring fewer capacitors.
Adjusting the flow in crucial areas can maximize the overall throughput of traffic along a stretch of road. This is of particular interest in regions of high traffic density, which may be caused by high volume peak time traffic, accidents or closure of one or more lanes of the road.
Implementation of channel estimation algorithms in ofdm for 64 subcarriersIAEME Publication
The document discusses channel estimation algorithms in OFDM systems with 64 subcarriers. It compares the performance of least squares (LS), linear minimum mean square error (LMMSE), and modified MMSE channel estimation algorithms for different modulation schemes including PSK and QAM. Simulation results show that the modified MMMSE algorithm, which considers a reduced channel correlation matrix, achieves a lower symbol error rate than LS and LMMSE, especially at high SNRs, with reduced computational complexity compared to LMMSE.
Orthogonal Frequency Division Multiplexing (OFDM) is of great interest for the development of
the fifth-generation technology. It is the cornerstone of Multiple-input multiple-output (MIMO) systems.
Even though inter carrier interference (ICI) and inter symbol interference (ISI) have been processed for
the fourth-generation standards, they still present a huge problem for the fifth-generation standards. This
paper explores the tradeoff between the length of the cyclic prefix and the performances of the OFDM
system. It also studies the effect of carrier frequency offset (CFO) on OFDM systems. A blind frequency
offset estimator that uses the correlations between the remodulated sequence in the receiver side and
the conventional received symbol is presented and a closed form solution is derived. The proposed
estimator is derived under short interval when the correlation is high, so it has low computational
complexity. Lin and Beek’s estimators are used for comparison. Simulations demonstrate the effectiveness
of the proposed estimator under Rayleigh fading channel.
EVALUATION OF MIMO SYSTEM CAPACITY OVER RAYLEIGH FADING CHANNELIJCSES Journal
High transmission data rate, spectral efficiency and reliability are essential for future wireless
communications systems. MIMO (multi-input multi-output) diversity technique is a band width efficient
system achieving high data transmission which eventually establishing a high capacity communication
system. Without needing to increase the transmitted power or the channel bandwidth, gain in capacity can
be considerably improved by varying the number of antennas on both sides. Correlated and uncorrelated
channels MIMO system was considered in this paper for different number of antennas and different SNR
over Rayleigh fading channel. At the transmitter both CSI(channel state information) technique and Water
filling power allocation principle was also considered in this paper.
This document summarizes a B.Tech project thesis defense on distributed learning and adaptation in cognitive radio. The project aimed to develop a decentralized learning system to map secondary users to idle primary network channels without collision. The methodology used a novel Distributed Learning and Adaptive algorithm (DALA) policy based on stochastic learning and an Upper Confidence Bound algorithm. Simulation results showed the DALA policy converged channel selection probabilities and secondary users were assigned different channels. Mini-batch stochastic learning improved performance over DALA by reducing regret. Thresholding channel probabilities provided faster convergence. Future work may include variable step sizes, dynamic channel availability, and new ranking schemes.
Projected Barzilai-Borwein Methods Applied to Distributed Compressive Spectru...Polytechnique Montreal
Cognitive radio allows unlicensed (cognitive) users to use licensed frequency bands by exploiting spectrum sensing techniques to detect whether or not the licensed (primary) users are present. In this paper, we present a compressed sensing applied to spectrum-occupancy detection in wide-band applications. The collected analog signals from each cognitive radio (CR) receiver at a fusion center are transformed to discrete-time signals by using analog-to-information converter (AIC) and then employed to calculate the autocorrelation. For signal reconstruction, we exploit a novel approach to solve the optimization problem consisting of minimizing both a quadratic (l2) error term and an l1-regularization term. In specific, we propose the Basic gradient projection (GP) and projected Barzilai-Borwein (PBB) algorithm to offer a better performance in terms of the mean squared error of the power spectrum density estimate and the detection probability of licensed signal occupancy.
These slides deal with the basic problem of channel equalization and exposes the issue related to it and shows how it can be balanced by the usage of effective and robust algorithms.
The document proposes a new channel estimation algorithm called ICEA-DA for MIMO-OFDM systems. ICEA-DA uses least squares estimation with discrete Fourier transform and integrates it with a differential evolution technique. It is placed at the central part of the MIMO-OFDM system between the transmitter and receiver blocks. The proposed method is evaluated for a 2x4 MIMO system using QPSK modulation. Results show ICEA-DA provides better performance than existing techniques in terms of bit error rate, peak signal-to-noise ratio, channel capacity, and symbol error rate.
Hybrid Adaptive Channel Estimation Technique in Time and Frequency Domain for...Tamilarasan N
This document summarizes a research paper that proposes a hybrid adaptive channel estimation technique for MIMO-OFDM wireless communication systems. The technique integrates channel estimation in the time domain and frequency domain. It uses column-based time domain estimation initially and switches to row-based frequency domain estimation when channel quality is good and bit error rate is low. It switches back to time domain estimation when channel quality worsens. The goal is to adaptively estimate the channel under different conditions. Experimental results showed the proposed hybrid technique outperformed other methods.
IRJET- Compressed Sensing based Modified Orthogonal Matching Pursuit in DTTV ...IRJET Journal
This document discusses a modified orthogonal matching pursuit algorithm used for channel estimation in digital terrestrial television systems. It proposes using compressed sensing based channel estimation at the receiver to eliminate sparse information. Thresholding is used to remove noise from the channel estimation and improve signal quality. Simulation results show that bit error rate decreases when the received signal power from different transmitters is almost equal.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
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.
International Journal of Engineering and Science Invention (IJESI)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.
Intersymbol interference caused by multipath in band limited frequency selective time dispersive channels distorts the transmitted signal, causing bit error at receiver. ISI is the major obstacle to high speed data transmission over wireless channels. Channel estimation is a technique used to combat the intersymbol interference. The objective of this paper is to improve channel estimation accuracy in MIMO-OFDM system by using modified variable step size leaky Least Mean Square (MVSSLLMS) algorithm proposed for MIMO OFDM System. So we are going to analyze Bit Error Rate for different signal to noise ratio, also compare the proposed scheme with standard LMS channel estimation method.
Enhancement of New Channel Equalizer Using Adaptive Neuro Fuzzy Inference SystemIOSR Journals
The document proposes a new channel equalizer based on adaptive neuro-fuzzy inference system (ANFIS) to reduce intersymbol interference over communication channels. Simulation results show the proposed equalizer has better bit error rate performance than multilayer perceptron and least mean square equalizers, and comparable performance to radial basis function network and optimal Bayesian equalizers, but with lower structural complexity than RBFN. The ANFIS equalizer combines the learning ability of neural networks and the reasoning of fuzzy systems to adaptively equalize linear and nonlinear channels.
Enhancement of New Channel Equalizer Using Adaptive Neuro Fuzzy Inference SystemIOSR Journals
The rapidly increasing need for information communication requires higher speed data transmission over the existing channels. The data rate over these channels is limited mainly by Inter Symbol Interference (ISI). Channel equalizers are used to reduce the effect of ISI. In this paper, a new equalizer based on Adaptive Neuro-Fuzzy Inference System is presented. The performance of the proposed equalizer is evaluated for both linear as well as non-linear channels in terms of bit-error rate for different noise powers. Simulation results show that the proposed equalizer has better Bit Error Rate (BER) performance compared to multi-layer perceptron and least mean square equalizers. However, its BER performance is slightly poorer than that of radial basis function network and optimal Bayesian equalizer but is better in terms of structural complexity.
The document summarizes key concepts in equalization and diversity techniques used in mobile communication systems. It discusses linear equalizers like transversal filters and lattice filters. Nonlinear equalizers covered include decision feedback equalization (DFE) and maximum likelihood sequence estimation (MLSE). DFE uses a feedforward filter and feedback filter to cancel intersymbol interference. MLSE estimates sequences using a trellis channel model and the Viterbi algorithm. Diversity techniques like spatial, frequency and time diversity are also introduced to mitigate fading effects.
The document discusses applying compressed sampling (CS) techniques for spectrum sensing and channel estimation in cognitive radio (CR) networks. It first provides background on CS theory, noting that signals can be reconstructed from fewer samples than required by Nyquist's theorem if the signal is sparse. It then proposes a compressed spectrum sensing scheme to detect wideband spectrum using sub-Nyquist sampling. After sensing, it formalizes the notion of sparse multipath channels and discusses estimating such channels using orthogonal matching pursuit. The effectiveness of these CS-based approaches is demonstrated through comparisons with conventional sensing and estimation methods.
This document provides an overview of equalization and diversity techniques used in mobile communication systems. It discusses how equalization is used to compensate for intersymbol interference caused by multipath fading. Linear equalizers aim to minimize mean square error, while nonlinear equalizers also use decision feedback. Common equalizer structures include transversal filters adapted using algorithms like LMS or RLS. Diversity techniques like spatial or frequency diversity compensate for fading by combining signals from multiple antennas or frequency bands. Channel coding adds redundancy to improve link performance in the presence of errors.
This document provides contact information for VENSOFT Technologies and describes 25 MATLAB projects for the 2013-2014 academic year related to signal processing topics such as phase noise estimation in MIMO systems, distributed averaging algorithms, channel estimation, computation of the moment generating function for lognormal distributions, compressed sensing of EEG data, and compressed sensing for wireless monitoring of fetal ECG signals. The contact for projects is provided as VENSOFT Technologies, their website, and a phone number.
This document discusses performance of matching algorithms for signal approximation. It begins by introducing matching pursuit algorithms like Orthogonal Matching Pursuit (OMP) and Stagewise Orthogonal Matching Pursuit (StOMP) which are greedy algorithms that approximate sparse signals. It then describes the Non-Negative Least Squares algorithm which solves non-negative least squares problems. Finally, it discusses Extranious Equivalent Detection (EED), a modification of OED that incorporates non-negativity of representations by using a non-negative optimization technique instead of orthogonal projection.
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.
Performance evaluation of high mobility OFDM channel estimation techniques IJECEIAES
In wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) has been adopted due to its robustness to multipath fading and high data rate transmissions. At the other hand, the performance of OFDM systems severely degraded due to multi-path fading and Doppler frequency shifts in mobile systems, which causes inter-carrier-interference (ICI). Thus, Estimation of channel parameters is required at the receiver using a pre designed estimator where pilot tones are inserted in each OFDM symbol. In this paper, a random pilot data are generated and inserted in each OFDM symbol at equally spaced locations. The performance test of Least Square (LS) and Linear Minimum Mean Square (LMMSE) estimation methods are proposed with Discrete Fourier Transform (DFT) based on both LS and LMMSE, where different ITU channel models are considered in order to compare their performance for data transmission in high mobile systems with different Doppler frequencies exceeds 200 Hz and minimal number of pilots.
Similar to Blind PNLMS Adaptive Algorithm for SIMO FIR Channel Estimation (20)
Performance evaluation of high mobility OFDM channel estimation techniques
Blind PNLMS Adaptive Algorithm for SIMO FIR Channel Estimation
1. GROUP MEMBERS: ISHTIAQUE AL MAHMUD (022469) AHSANUR RAHMAN (022464) JABED HASAN (022473) PROJECT SUPERVISOR: Prof. Md. KAMRUL HASAN EEE, BUET Blind PNLMS Adaptive Algorithm for SIMO FIR Channel Estimation
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8. Performance curve for FSSLMS Performance Index, Number of channel, M=5 Length of impulse response, L =32 SNR=high µ=1