Constellation shaping introduced to maximize channel capacity is detrimental to the performance of many cost function-based blind equalization algorithms including the constant modulus algorithm (CMA). We propose a ne...
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Constellation shaping introduced to maximize channel capacity is detrimental to the performance of many cost function-based blind equalization algorithms including the constant modulus algorithm (CMA). We propose a new multi-modulusalgorithm closely related to CMA, but robust against changes in the statistical nature of the signal due to constellation shaping. While CMA behaves properly only for sub-Gaussian distributions, the algorithm we develop is applicable to a broad class of distributions including Gaussian and super-Gaussian.
A novel multitarget constantmodulus array structure is proposed for CDMA systems in this paper. The new algorithm for the structure is called pre- despreading and wavelet denoising constant modulu
A novel multitarget constantmodulus array structure is proposed for CDMA systems in this paper. The new algorithm for the structure is called pre- despreading and wavelet denoising constant modulu
Due to some drawbacks such as instability of the analog receiver in wideband conditions, all-digital parallel receiver (APRX) has become more and more attractive. Based on the structure of an APRX, which is presented ...
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ISBN:
(纸本)0780386477
Due to some drawbacks such as instability of the analog receiver in wideband conditions, all-digital parallel receiver (APRX) has become more and more attractive. Based on the structure of an APRX, which is presented in Telecommunications and Data Acquisition (TDA) progress report of Jet Propulsion Laboratory (JPL), a novel parallel algorithm for fractionally spaced equalization (PFSE) is proposed. Utilizing the constant modulus algorithm (CMA), PFSE takes best advantage of its data overlapping characteristic and achieves perfect combination with the APRX's structure. Simulation results show that the performance of PFSE obviously predominates that of the T-Spaced Equalizer, with hardly any loss of performance compared with the corresponding serial FSE.
For greatly overcoming disadvantages of low convergent rate and high mean square error of constant modulus algorithm(CMA) and defects of high computational complexity of polyspectra algorithms, sign kurtosis maximizat...
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ISBN:
(纸本)0780386531
For greatly overcoming disadvantages of low convergent rate and high mean square error of constant modulus algorithm(CMA) and defects of high computational complexity of polyspectra algorithms, sign kurtosis maximization adaptive algorithm (SKMAA) for updating blind equalizer weight vectors is developed based on kurtosis of stochastic signals, the stochastic ascend approach, and sign algorithm. In this algorithm, the sign of the equalizer output signal function is extracted and used as the updating factor of equalizer weight vectors to decrease the computational load of updating blind equalizer weight vectors. Accordingly, performance of the SKMAA in convergent speed and residual mean square error (MSE) is much better than that of CMA. The efficiency of SKMAA is proved via computer simulation of the underwater acoustic channel (UWAC) equalization.
This work proposes a framework to determine the optimal Wiener equalizer by using an artificial immune network model together with the constantmodulus (CM) cost function. This study was primarily motivated by recent ...
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This work proposes a framework to determine the optimal Wiener equalizer by using an artificial immune network model together with the constantmodulus (CM) cost function. This study was primarily motivated by recent theoretical results concerning the CM criterion and its relation to the Wiener approach. The proposed immune-based technique was tested under different channel models and filter orders, and benchmarked against a procedure using a genetic algorithm with niching. The results demonstrated that the proposed strategy has a clear superiority when compared with the more traditional technique. The proposed algorithm presents interesting features from the perspective of multimodal search, being capable of determining the optimal Wiener equalizer in most runs for all tested channels.
constant modulus algorithm (CMA) for blind multiuser detection is proposed in [3]. However, the first type of stationary points in [3] is not correct. A general expression for the solutions is given in this paper, whi...
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constant modulus algorithm (CMA) for blind multiuser detection is proposed in [3]. However, the first type of stationary points in [3] is not correct. A general expression for the solutions is given in this paper, which shows there are many undesired stationary points. Therefore, methods that guarantee CMA to converge to the desired point are needed. We present approximate conditions that set initialization in the lock region. Simulation shows that CMA with variable step size has quicker convergence speed than MOE-RLS, while obtaining better performance.
In this correspondence, we extend the results from Wang and Dowling to provide a low-cost and high performance blind adaptive interference suppression scheme for CDMA systems. Simulation results confirm that the propo...
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In this correspondence, we extend the results from Wang and Dowling to provide a low-cost and high performance blind adaptive interference suppression scheme for CDMA systems. Simulation results confirm that the proposed algorithm outperforms several existing algorithms, even under the most severe cases of near-far and multipath conditions.
The constantmodulus (CM) criterion coupled with a gradient search helps in the design of fractionally spaced equalizers. Effective implementation of CIM algorithm requires proper choice of the scale factor mu called ...
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ISBN:
(纸本)0780365143
The constantmodulus (CM) criterion coupled with a gradient search helps in the design of fractionally spaced equalizers. Effective implementation of CIM algorithm requires proper choice of the scale factor mu called the step size and initialization of equalizer coefficients. Experience reveals that these two determine the convergence rate and final misadjustment. Recently Brown et al proposed a computationally efficient algorithm, which is a signed error version of CMA. This paper proposes yet another variation of the same and reports faster convergence. The idea is to use a variable step size, which increases the convergence rare.
This paper proposed to use the Joint Approximate Diagonalisation of Eigen Matrices (JADE) algorithm for the cascade multistage constantmodulus (CM) array in order to recover correlated cochannel signals in the multip...
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ISBN:
(纸本)0780379543
This paper proposed to use the Joint Approximate Diagonalisation of Eigen Matrices (JADE) algorithm for the cascade multistage constantmodulus (CM) array in order to recover correlated cochannel signals in the multipath environment. The JADE algorithm was need as the initial-weight estimator. Furthermore, we propose a concept to compromise between the high computational complexity of the JADE algorithm and the degradation of the signal-captured performance of the cascade multistage CM array as well. The experimental results show that this scheme has the signal-captured performance close to MVDR array technique, which is the best, in comparison with our proposed scheme, and the original cascade multistage CM array.
Decision feedback equalisers offer a good compromise between complexity and performance for channels with strong intersymbol interference. However, their blind or decision-directed adaptation may converge to degenerat...
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Decision feedback equalisers offer a good compromise between complexity and performance for channels with strong intersymbol interference. However, their blind or decision-directed adaptation may converge to degenerative solutions for which signal at the equaliser's output is independent of its input. The known algorithms proposed to solve this problem, are evaluated in this paper. It is shown that their main defect is a lack of well-defined criteria allowing the detection of degenerative solutions, so this paper introduces a criterion proved to be sufficient for reliable detection of such solutions. Using the new criterion, an algorithm of blind decision feedback equalisation, based on constrained optimisation, is proposed. The new algorithm does not admit degenerative solutions therefore should be preferred among the analysed algorithms. Also, the problem of false phase lock, characteristic of some modulations, is addressed and a solution to it is proposed. The results of the study are presented using the experimental data and simulation. (C) 2002 Elsevier Science B.V. All rights reserved.
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