The Experts below are selected from a list of 148323 Experts worldwide ranked by ideXlab platform
Lajos Hanzo - One of the best experts on this subject based on the ideXlab platform.
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multiple antenna aided ofdm employing genetic algorithm assisted minimum Bit Error Rate multiuser detection
IEEE Transactions on Vehicular Technology, 2005Co-Authors: Mohamad Yusoff Alias, Sheng Chen, Lajos HanzoAbstract:The family of minimum Bit Error Rate (MBER) multiuser detectors (MUD) is capable of outperforming the classic minimum mean-squared Error (MMSE) MUD in terms of the achievable Bit-Error Rate (BER) owing to directly minimizing the BER cost function. In this paper, we will invoke genetic algorithms (GAs) for finding the optimum weight vectors of the MBER MUD in the context of multiple-antenna-aided multiuser orthogonal frequency division multiplexing (OFDM) . We will also show that the MBER MUD is capable of supporting more users than the number of receiver antennas available, while outperforming the MMSE MUD.
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Adaptive minimum Bit-Error Rate beamforming
IEEE Transactions on Wireless Communications, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos HanzoAbstract:An adaptive beamforming technique is proposed based on directly minimizing the Bit-Error Rate (BER). It is demonstRated that this minimum BER (MBER) approach utilizes the antenna array elements more intelligently than the standard minimum mean square Error (MMSE) approach. Consequently, MBER beamforming is capable of providing significant performance gains in terms of a reduced BER over MMSE beamforming. A block-data adaptive implementation of the MBER beamforming solution is developed based on the Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is considered, and a stochastic gradient algorithm, referred to as the least Bit Error Rate, is derived. The proposed adaptive MBER beamforming technique provides an extension to the existing work for adaptive MBER equalization and multiuser detection.
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Adaptive minimum Bit Error Rate beamforming assisted receiver for QPSK wireless communication
Digital Signal Processing, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos Hanzo, Andreas WolfgangAbstract:This paper considers interference limited communication systems where the desired user and interfering users are symbol-synchronized. A novel adaptive beamforming technique is proposed for quadrature phase shift keying (QPSK) receiver based directly on minimizing the Bit Error Rate. It is demonstRated that the proposed minimum Bit Error Rate (MBER) approach utilizes the system resource (antenna array elements) more intelligently, than the standard minimum mean square Error (MMSE) approach. Consequently, an MBER beamforming assisted receiver is capable of providing significant performance gains in terms of a reduced Bit Error Rate over an MMSE beamforming one. A block-data based adaptive implementation of the theoretical MBER beamforming solution is developed based on the classical Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is also considered, and a stochastic gradient algorithm, called the least Bit Error Rate, is derived for the beamforming assisted QPSK receiver.
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ICC - Adaptive minimum Bit Error Rate beamforming assisted QPSK receiver
2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577), 2004Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos Hanzo, Andreas WolfgangAbstract:A novel adaptive beamforming technique is proposed for wireless communication with quadrature phase shift keying signalling based on the minimum Bit Error Rate (MBER) criterion. It is shown that the MBER approach provides significant performance gain in terms of smaller Bit Error Rate over the standard minimum mean square Error approach. Using the classical Parzen window estimate of probability density function, both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed.
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adaptive minimum Bit Error Rate beamforming assisted receiver for wireless communications
International Conference on Acoustics Speech and Signal Processing, 2003Co-Authors: Sheng Chen, Lajos Hanzo, Nurul Nadia AhmadAbstract:A novel adaptive beamforming technique is proposed for wireless communication application based on the minimum Bit Error Rate (MBER) criterion. It is shown that the MBER approach provides significant performance gain in terms of smaller Bit Error Rate (BER) over the standard minimum mean square Error (MMSE) approach. Using the classical Parzen window estimate of probability density function (p.d.f.), both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed.
Sheng Chen - One of the best experts on this subject based on the ideXlab platform.
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multiple antenna aided ofdm employing genetic algorithm assisted minimum Bit Error Rate multiuser detection
IEEE Transactions on Vehicular Technology, 2005Co-Authors: Mohamad Yusoff Alias, Sheng Chen, Lajos HanzoAbstract:The family of minimum Bit Error Rate (MBER) multiuser detectors (MUD) is capable of outperforming the classic minimum mean-squared Error (MMSE) MUD in terms of the achievable Bit-Error Rate (BER) owing to directly minimizing the BER cost function. In this paper, we will invoke genetic algorithms (GAs) for finding the optimum weight vectors of the MBER MUD in the context of multiple-antenna-aided multiuser orthogonal frequency division multiplexing (OFDM) . We will also show that the MBER MUD is capable of supporting more users than the number of receiver antennas available, while outperforming the MMSE MUD.
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Adaptive minimum Bit Error Rate beamforming assisted receiver for QPSK wireless communication
Digital Signal Processing, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos Hanzo, Andreas WolfgangAbstract:This paper considers interference limited communication systems where the desired user and interfering users are symbol-synchronized. A novel adaptive beamforming technique is proposed for quadrature phase shift keying (QPSK) receiver based directly on minimizing the Bit Error Rate. It is demonstRated that the proposed minimum Bit Error Rate (MBER) approach utilizes the system resource (antenna array elements) more intelligently, than the standard minimum mean square Error (MMSE) approach. Consequently, an MBER beamforming assisted receiver is capable of providing significant performance gains in terms of a reduced Bit Error Rate over an MMSE beamforming one. A block-data based adaptive implementation of the theoretical MBER beamforming solution is developed based on the classical Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is also considered, and a stochastic gradient algorithm, called the least Bit Error Rate, is derived for the beamforming assisted QPSK receiver.
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Adaptive minimum Bit-Error Rate beamforming
IEEE Transactions on Wireless Communications, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos HanzoAbstract:An adaptive beamforming technique is proposed based on directly minimizing the Bit-Error Rate (BER). It is demonstRated that this minimum BER (MBER) approach utilizes the antenna array elements more intelligently than the standard minimum mean square Error (MMSE) approach. Consequently, MBER beamforming is capable of providing significant performance gains in terms of a reduced BER over MMSE beamforming. A block-data adaptive implementation of the MBER beamforming solution is developed based on the Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is considered, and a stochastic gradient algorithm, referred to as the least Bit Error Rate, is derived. The proposed adaptive MBER beamforming technique provides an extension to the existing work for adaptive MBER equalization and multiuser detection.
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Adaptive minimum Bit-Error-Rate filtering
IEE Proceedings - Vision Image and Signal Processing, 2004Co-Authors: Sheng ChenAbstract:Adaptive filtering has traditionally been developed based on the minimum mean square Error (MMSE) principle and has found ever-increasing applications in communications. The paper develops adaptive filtering based on an alternative minimum Bit Error Rate (MBER) criterion for communication applications. It is shown that the MBER filtering exploits the non-Gaussian distribution of filter output effectively and, consequently, can provide significant performance gain in terms of smaller Bit Error Rate (BER) over the MMSE approach. Adopting the classical Parzen window or kernel density estimation for a probability density function (pdf), a block-data gradient adaptive MBER algorithm is derived. A stochastic gradient adaptive MBER algorithm is further developed for sample-by-sample adaptive implementation of the MBER filtering. Extension of the MBER approach to adaptive nonlinear filtering is also discussed.
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Least Bit Error Rate Adaptive Multiuser Detection
Soft Computing in Communications, 2004Co-Authors: Sheng ChenAbstract:Linear detector required at direct-sequence code division multiple access (DS-CDMA)communication systems is classically designed based on the minimum mean squares Error (MMSE) criterion, which can efficiently be implemented using the standard adaptive algorithms, such as the least mean square (LMS) algorithm. As the probability distribution of the linear detector's soft output is generally non-Gaussian,the MMSE solution can be far away from the optimal minimum Bit Error Rate (MBER) solution. Adopting a non-Gaussian approach naturally leads to the MBER linear detector. Based on the approach of Parzen window or kernel density estimation for approximating the probability density function (p.d.f.), a stochastic gradient adaptive MBER algorithm, called the least Bit Error Rate (LBER), is developed for training a linear multiuser detector. A simplified or approximate LBER (ALBER) algorithm is particularly promising, as it has a computational complexity similar to that of the classical LMS algorithm. Furthermore, this ALBER algorithm can be extended to the nonlinear multiuser detection.
Alex Grant - One of the best experts on this subject based on the ideXlab platform.
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Bit Error Rate estimation for turbo decoding
IEEE Transactions on Communications, 2009Co-Authors: Nick Letzepis, Alex GrantAbstract:In this paper we propose a method for on-line estimation of Bit Error Rate during turbo decoding. We model the log-likelihood ratios as a mixture of two Gaussian random variables and derive estimators for the mean and variance of these distributions based on a maximum-likelihood approach. The parameter estimates are then employed to calculate the cross-over area of the Gaussian tails to estimate BER at each decoder iteration. The performance of the BER estimator is analysed and compared.
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Bit Error Rate estimation for turbo decoding
IEEE International Symposium on Information Theory 2003. Proceedings., 2003Co-Authors: Nick Letzepis, Alex GrantAbstract:We propose a method for on-line estimation of the Bit Error Rate (BER) during turbo decoding. The Gaussian assumption has been widely used in analysing the convergence behavior of turbo codes.
Nurul Nadia Ahmad - One of the best experts on this subject based on the ideXlab platform.
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Adaptive minimum Bit-Error Rate beamforming
IEEE Transactions on Wireless Communications, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos HanzoAbstract:An adaptive beamforming technique is proposed based on directly minimizing the Bit-Error Rate (BER). It is demonstRated that this minimum BER (MBER) approach utilizes the antenna array elements more intelligently than the standard minimum mean square Error (MMSE) approach. Consequently, MBER beamforming is capable of providing significant performance gains in terms of a reduced BER over MMSE beamforming. A block-data adaptive implementation of the MBER beamforming solution is developed based on the Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is considered, and a stochastic gradient algorithm, referred to as the least Bit Error Rate, is derived. The proposed adaptive MBER beamforming technique provides an extension to the existing work for adaptive MBER equalization and multiuser detection.
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Adaptive minimum Bit Error Rate beamforming assisted receiver for QPSK wireless communication
Digital Signal Processing, 2005Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos Hanzo, Andreas WolfgangAbstract:This paper considers interference limited communication systems where the desired user and interfering users are symbol-synchronized. A novel adaptive beamforming technique is proposed for quadrature phase shift keying (QPSK) receiver based directly on minimizing the Bit Error Rate. It is demonstRated that the proposed minimum Bit Error Rate (MBER) approach utilizes the system resource (antenna array elements) more intelligently, than the standard minimum mean square Error (MMSE) approach. Consequently, an MBER beamforming assisted receiver is capable of providing significant performance gains in terms of a reduced Bit Error Rate over an MMSE beamforming one. A block-data based adaptive implementation of the theoretical MBER beamforming solution is developed based on the classical Parzen window estimate of probability density function. Furthermore, a sample-by-sample adaptive implementation is also considered, and a stochastic gradient algorithm, called the least Bit Error Rate, is derived for the beamforming assisted QPSK receiver.
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ICC - Adaptive minimum Bit Error Rate beamforming assisted QPSK receiver
2004 IEEE International Conference on Communications (IEEE Cat. No.04CH37577), 2004Co-Authors: Sheng Chen, Nurul Nadia Ahmad, Lajos Hanzo, Andreas WolfgangAbstract:A novel adaptive beamforming technique is proposed for wireless communication with quadrature phase shift keying signalling based on the minimum Bit Error Rate (MBER) criterion. It is shown that the MBER approach provides significant performance gain in terms of smaller Bit Error Rate over the standard minimum mean square Error approach. Using the classical Parzen window estimate of probability density function, both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed.
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adaptive minimum Bit Error Rate beamforming assisted receiver for wireless communications
International Conference on Acoustics Speech and Signal Processing, 2003Co-Authors: Sheng Chen, Lajos Hanzo, Nurul Nadia AhmadAbstract:A novel adaptive beamforming technique is proposed for wireless communication application based on the minimum Bit Error Rate (MBER) criterion. It is shown that the MBER approach provides significant performance gain in terms of smaller Bit Error Rate (BER) over the standard minimum mean square Error (MMSE) approach. Using the classical Parzen window estimate of probability density function (p.d.f.), both the block-data and sample-by-sample adaptive implementations of the MBER solution are developed.
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Genetic algorithm assisted minimum Bit Error Rate beamforming
2004 IEEE 59th Vehicular Technology Conference. VTC 2004-Spring (IEEE Cat. No.04CH37514), 1Co-Authors: Andreas Wolfgang, Sheng Chen, Nurul Nadia Ahmad, Lajos HanzoAbstract:A novel genetic algorithm (GA) assisted minimum Bit Error Rate (MBER) beamforming technique is introduced. The performance of the proposed GAs is characterised by the probability density function (PDF) and the mean value of the achievable Bit Error Rate (BER) at the beamformer's output. The results are also compared to the theoretical bounds. It is shown that GAs are suitable for MBER beamforming and that a trade-off between the complexity of the GA and its robustness against system parameter variations can be found.
Nick Letzepis - One of the best experts on this subject based on the ideXlab platform.
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Bit Error Rate estimation for turbo decoding
IEEE Transactions on Communications, 2009Co-Authors: Nick Letzepis, Alex GrantAbstract:In this paper we propose a method for on-line estimation of Bit Error Rate during turbo decoding. We model the log-likelihood ratios as a mixture of two Gaussian random variables and derive estimators for the mean and variance of these distributions based on a maximum-likelihood approach. The parameter estimates are then employed to calculate the cross-over area of the Gaussian tails to estimate BER at each decoder iteration. The performance of the BER estimator is analysed and compared.
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Bit Error Rate estimation for turbo decoding
IEEE International Symposium on Information Theory 2003. Proceedings., 2003Co-Authors: Nick Letzepis, Alex GrantAbstract:We propose a method for on-line estimation of the Bit Error Rate (BER) during turbo decoding. The Gaussian assumption has been widely used in analysing the convergence behavior of turbo codes.
