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Faouzi Bader - One of the best experts on this subject based on the ideXlab platform.
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Blind Equalization using Constant Modulus Algorithm Adapted to OFDM/OQAM Modulation
2016Co-Authors: Vincent Savaux, Faouzi Bader, Malek NaouesAbstract:It has been proved that the Blind Equalization using constant modulus algorithm (CMA) is a possible solution for channel inversion in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM). However, the existing solution does not consider the residual interference that remains after Equalization, and which is inherent to this type of modulation. In this paper, we propose to reconsider the value of the dispersion parameter in the update algorithm by taking into account this interference in order to enhance the Blind Equalization performance. The improvement of the CMA in OFDM/OQAM by means of the proposed change of parameter is demonstrated through both theoretical and numerical results.
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CMA-Based Blind Equalization and Phase Recovery in OFDM/OQAM Systems
2016Co-Authors: Vincent Savaux, Faouzi Bader, Jacques PalicotAbstract:This paper deals with a constant modulus algorithm-(CMA) based Blind Equalization method for orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) scheme. The authors propose to combine the CMA with a low-pass filter in order to increase the convergence speed of the equalizer, and to avoid the detection of the received symbols with phase mismatch. Simulations results show that the convergence speed is largely increased, and the proposed method achieves bit error rate (BER) performance very close to that of the perfect channel estimation and Equalization. Index Terms—Blind Equalization, OFDM/OQAM, CMA, Impulse Noise Cancellation. I. INTRODUCTION The Blind Equalization is an interesting solution for the channel inversion (or deconvolution) since it guarantees the signal a maximum spectral efficiency. Indeed, these techniques do not use pilots, the Blind equalizer only takes advantage of a few signal features to perform the channel inversion. In [1], B. Farhang-Boroujeny has adapted the Blind Equalization using the constant modulus algorithm (CMA) proposed by D. N. Godard in [2] to the cosine modulated filter bank (CMFB) modulation. In [3] the authors proposed to use the second order moment of the received signal, while the CMA is used in [1]. In filter bank multicarrier (FBMC), and in particular in orthgonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM), only few papers deals with Blind Equalization. Due the convergence delay of the Blind methods and the uncertainty on the phase of the recovered symbols, the Blind channel Equalization remains a pending challenge not much studied by the scientific community, in particular in FBMC. In this paper we propose a constant modulus algorithm-based (CMA) Blind equalizer for OFDM/OQAM systems. As in [1], we consider a one-tap per carrier Equalization, since it is particularly adapted to the multicarrier systems. As mentioned in [4], this type of technique may lead to local solutions and implies that the symbols are detected with a phase shift of 0 or π. The proposed method consists of filtering the equalizer response in order to smooth the channel frequency response. The principle of the proposed technique is simple, since it is similar to a low-pass filter as used in channel estimation [5]. The addition of a differential phase coding allows to suppress any uncertainty on the phase of the recovered symbols.
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OFDM/OQAM Blind Equalization Using CNA Approach OFDM/OQAM Blind Equalization Using CNA Approach
IEEE Transactions on Signal Processing, 2016Co-Authors: Vincent Savaux, Jacques Palicot, Faouzi BaderAbstract:This paper deals with Blind Equalization based on the constant norm algorithm (CNA) in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM). The CNA is designed to fit the complex square constellations with high order. As a consequence, the received signal is reshaped in order to change the real OQAM symbols into complex ones. Although it increases the intrinsic interferences of the OFDM/OQAM signal, it is proved by analysis and through simulations that the CNA with proposed reshaped signal achieves better mean square error (MSE) performance than CMA applied to the received OFDM/OQAM signal. Furthermore, a sub-optimal initialization strategy is proposed, which ensures a high convergence speed. The behavior of the proposed Blind Equalization method is analyzed under synchronization mismatch as well as in time-varying propagation environment.
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Ultra-Fast Blind Equalization for OFDM: Principle and Steps Towards Implementation
2015Co-Authors: Vincent Savaux, Faouzi Bader, Malek Naoues, Jacques PalicotAbstract:Blind Equalization allows the transmitted signals to maximize their spectral efficiency, but it is limited by the convergence time of used algorithms. In this paper, the authors propose a new frequency Blind Equalization method for orthogonal frequency division multiplexing (OFDM), which drastically reduces the transient state delay of the algorithm’s convergence process. It consists of reusing a proper number of received OFDM symbols that have been stored in a memory. Simulations results reveal that a quasi-instantaneous Equalization process can be achieved. In addition, the implementation issues are discussed in this paper.
Vincent Savaux - One of the best experts on this subject based on the ideXlab platform.
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Blind Equalization using Constant Modulus Algorithm Adapted to OFDM/OQAM Modulation
2016Co-Authors: Vincent Savaux, Faouzi Bader, Malek NaouesAbstract:It has been proved that the Blind Equalization using constant modulus algorithm (CMA) is a possible solution for channel inversion in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM). However, the existing solution does not consider the residual interference that remains after Equalization, and which is inherent to this type of modulation. In this paper, we propose to reconsider the value of the dispersion parameter in the update algorithm by taking into account this interference in order to enhance the Blind Equalization performance. The improvement of the CMA in OFDM/OQAM by means of the proposed change of parameter is demonstrated through both theoretical and numerical results.
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CMA-Based Blind Equalization and Phase Recovery in OFDM/OQAM Systems
2016Co-Authors: Vincent Savaux, Faouzi Bader, Jacques PalicotAbstract:This paper deals with a constant modulus algorithm-(CMA) based Blind Equalization method for orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) scheme. The authors propose to combine the CMA with a low-pass filter in order to increase the convergence speed of the equalizer, and to avoid the detection of the received symbols with phase mismatch. Simulations results show that the convergence speed is largely increased, and the proposed method achieves bit error rate (BER) performance very close to that of the perfect channel estimation and Equalization. Index Terms—Blind Equalization, OFDM/OQAM, CMA, Impulse Noise Cancellation. I. INTRODUCTION The Blind Equalization is an interesting solution for the channel inversion (or deconvolution) since it guarantees the signal a maximum spectral efficiency. Indeed, these techniques do not use pilots, the Blind equalizer only takes advantage of a few signal features to perform the channel inversion. In [1], B. Farhang-Boroujeny has adapted the Blind Equalization using the constant modulus algorithm (CMA) proposed by D. N. Godard in [2] to the cosine modulated filter bank (CMFB) modulation. In [3] the authors proposed to use the second order moment of the received signal, while the CMA is used in [1]. In filter bank multicarrier (FBMC), and in particular in orthgonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM), only few papers deals with Blind Equalization. Due the convergence delay of the Blind methods and the uncertainty on the phase of the recovered symbols, the Blind channel Equalization remains a pending challenge not much studied by the scientific community, in particular in FBMC. In this paper we propose a constant modulus algorithm-based (CMA) Blind equalizer for OFDM/OQAM systems. As in [1], we consider a one-tap per carrier Equalization, since it is particularly adapted to the multicarrier systems. As mentioned in [4], this type of technique may lead to local solutions and implies that the symbols are detected with a phase shift of 0 or π. The proposed method consists of filtering the equalizer response in order to smooth the channel frequency response. The principle of the proposed technique is simple, since it is similar to a low-pass filter as used in channel estimation [5]. The addition of a differential phase coding allows to suppress any uncertainty on the phase of the recovered symbols.
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OFDM/OQAM Blind Equalization Using CNA Approach OFDM/OQAM Blind Equalization Using CNA Approach
IEEE Transactions on Signal Processing, 2016Co-Authors: Vincent Savaux, Jacques Palicot, Faouzi BaderAbstract:This paper deals with Blind Equalization based on the constant norm algorithm (CNA) in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM). The CNA is designed to fit the complex square constellations with high order. As a consequence, the received signal is reshaped in order to change the real OQAM symbols into complex ones. Although it increases the intrinsic interferences of the OFDM/OQAM signal, it is proved by analysis and through simulations that the CNA with proposed reshaped signal achieves better mean square error (MSE) performance than CMA applied to the received OFDM/OQAM signal. Furthermore, a sub-optimal initialization strategy is proposed, which ensures a high convergence speed. The behavior of the proposed Blind Equalization method is analyzed under synchronization mismatch as well as in time-varying propagation environment.
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Ultra-Fast Blind Equalization for OFDM: Principle and Steps Towards Implementation
2015Co-Authors: Vincent Savaux, Faouzi Bader, Malek Naoues, Jacques PalicotAbstract:Blind Equalization allows the transmitted signals to maximize their spectral efficiency, but it is limited by the convergence time of used algorithms. In this paper, the authors propose a new frequency Blind Equalization method for orthogonal frequency division multiplexing (OFDM), which drastically reduces the transient state delay of the algorithm’s convergence process. It consists of reusing a proper number of received OFDM symbols that have been stored in a memory. Simulations results reveal that a quasi-instantaneous Equalization process can be achieved. In addition, the implementation issues are discussed in this paper.
Guy A. Dumont - One of the best experts on this subject based on the ideXlab platform.
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the multimodulus Blind Equalization and its generalized algorithms
IEEE Journal on Selected Areas in Communications, 2002Co-Authors: Jian Yang, J.-j. Werner, Guy A. DumontAbstract:This paper presents a new Blind Equalization algorithm called multimodulus algorithm (MMA). This algorithm combines the benefits of the well-known reduced constellation algorithm (RCA) and constant modulus algorithm (CMA). In addition, MMA provides more flexibility than RCA and CMA, and is better suited to take advantage of the symbol statistics of certain types of signal constellations, such as nonsquare constellations, very dense constellations, and some wrong solutions.
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Blind Equalization for broadband access
IEEE Communications Magazine, 1999Co-Authors: J.-j. Werner, Jian Yang, D.d. Harman, Guy A. DumontAbstract:This article discusses the general principles of Blind Equalization and its use in emerging broadband access applications such as FTTC and xDSL. New results obtained for these applications are also presented.
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The multimodulus Blind Equalization algorithm
Proceedings of 13th International Conference on Digital Signal Processing, 1Co-Authors: Jian Yang, J.-j. Werner, Guy A. DumontAbstract:This paper presents a new Blind Equalization algorithm called the multimodulus algorithm (MMA). This algorithm is particularly well suited to applications using two-dimensional transmission schemes such as carrierless AM/PM (CAP) and quadrature amplitude modulation (QAM). The paper also discusses some of the advantages provided by MMA when compared to traditional Blind Equalization algorithms, such as the reduced constellation algorithm (RCA) and the constant modulus algorithm (CMA).
Jacques Palicot - One of the best experts on this subject based on the ideXlab platform.
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CMA-Based Blind Equalization and Phase Recovery in OFDM/OQAM Systems
2016Co-Authors: Vincent Savaux, Faouzi Bader, Jacques PalicotAbstract:This paper deals with a constant modulus algorithm-(CMA) based Blind Equalization method for orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) scheme. The authors propose to combine the CMA with a low-pass filter in order to increase the convergence speed of the equalizer, and to avoid the detection of the received symbols with phase mismatch. Simulations results show that the convergence speed is largely increased, and the proposed method achieves bit error rate (BER) performance very close to that of the perfect channel estimation and Equalization. Index Terms—Blind Equalization, OFDM/OQAM, CMA, Impulse Noise Cancellation. I. INTRODUCTION The Blind Equalization is an interesting solution for the channel inversion (or deconvolution) since it guarantees the signal a maximum spectral efficiency. Indeed, these techniques do not use pilots, the Blind equalizer only takes advantage of a few signal features to perform the channel inversion. In [1], B. Farhang-Boroujeny has adapted the Blind Equalization using the constant modulus algorithm (CMA) proposed by D. N. Godard in [2] to the cosine modulated filter bank (CMFB) modulation. In [3] the authors proposed to use the second order moment of the received signal, while the CMA is used in [1]. In filter bank multicarrier (FBMC), and in particular in orthgonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM), only few papers deals with Blind Equalization. Due the convergence delay of the Blind methods and the uncertainty on the phase of the recovered symbols, the Blind channel Equalization remains a pending challenge not much studied by the scientific community, in particular in FBMC. In this paper we propose a constant modulus algorithm-based (CMA) Blind equalizer for OFDM/OQAM systems. As in [1], we consider a one-tap per carrier Equalization, since it is particularly adapted to the multicarrier systems. As mentioned in [4], this type of technique may lead to local solutions and implies that the symbols are detected with a phase shift of 0 or π. The proposed method consists of filtering the equalizer response in order to smooth the channel frequency response. The principle of the proposed technique is simple, since it is similar to a low-pass filter as used in channel estimation [5]. The addition of a differential phase coding allows to suppress any uncertainty on the phase of the recovered symbols.
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OFDM/OQAM Blind Equalization Using CNA Approach OFDM/OQAM Blind Equalization Using CNA Approach
IEEE Transactions on Signal Processing, 2016Co-Authors: Vincent Savaux, Jacques Palicot, Faouzi BaderAbstract:This paper deals with Blind Equalization based on the constant norm algorithm (CNA) in orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM). The CNA is designed to fit the complex square constellations with high order. As a consequence, the received signal is reshaped in order to change the real OQAM symbols into complex ones. Although it increases the intrinsic interferences of the OFDM/OQAM signal, it is proved by analysis and through simulations that the CNA with proposed reshaped signal achieves better mean square error (MSE) performance than CMA applied to the received OFDM/OQAM signal. Furthermore, a sub-optimal initialization strategy is proposed, which ensures a high convergence speed. The behavior of the proposed Blind Equalization method is analyzed under synchronization mismatch as well as in time-varying propagation environment.
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Ultra-Fast Blind Equalization for OFDM: Principle and Steps Towards Implementation
2015Co-Authors: Vincent Savaux, Faouzi Bader, Malek Naoues, Jacques PalicotAbstract:Blind Equalization allows the transmitted signals to maximize their spectral efficiency, but it is limited by the convergence time of used algorithms. In this paper, the authors propose a new frequency Blind Equalization method for orthogonal frequency division multiplexing (OFDM), which drastically reduces the transient state delay of the algorithm’s convergence process. It consists of reusing a proper number of received OFDM symbols that have been stored in a memory. Simulations results reveal that a quasi-instantaneous Equalization process can be achieved. In addition, the implementation issues are discussed in this paper.
Jian Yang - One of the best experts on this subject based on the ideXlab platform.
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the multimodulus Blind Equalization and its generalized algorithms
IEEE Journal on Selected Areas in Communications, 2002Co-Authors: Jian Yang, J.-j. Werner, Guy A. DumontAbstract:This paper presents a new Blind Equalization algorithm called multimodulus algorithm (MMA). This algorithm combines the benefits of the well-known reduced constellation algorithm (RCA) and constant modulus algorithm (CMA). In addition, MMA provides more flexibility than RCA and CMA, and is better suited to take advantage of the symbol statistics of certain types of signal constellations, such as nonsquare constellations, very dense constellations, and some wrong solutions.
-
Blind Equalization for broadband access
IEEE Communications Magazine, 1999Co-Authors: J.-j. Werner, Jian Yang, D.d. Harman, Guy A. DumontAbstract:This article discusses the general principles of Blind Equalization and its use in emerging broadband access applications such as FTTC and xDSL. New results obtained for these applications are also presented.
-
The multimodulus Blind Equalization algorithm
Proceedings of 13th International Conference on Digital Signal Processing, 1Co-Authors: Jian Yang, J.-j. Werner, Guy A. DumontAbstract:This paper presents a new Blind Equalization algorithm called the multimodulus algorithm (MMA). This algorithm is particularly well suited to applications using two-dimensional transmission schemes such as carrierless AM/PM (CAP) and quadrature amplitude modulation (QAM). The paper also discusses some of the advantages provided by MMA when compared to traditional Blind Equalization algorithms, such as the reduced constellation algorithm (RCA) and the constant modulus algorithm (CMA).