− This paper proposes an adaptive nonlinear channel equalizer by using combination of finite impulse response (FIR) filter and functional link artificial neural (FLANN) network (CFFLANN) capable of equalizing complex multilevel signals. The equalizer is designed to remove linear and nonlinear distortion produced by nonlinear channel. FLANN section removes the nonlinear distortions and FIR secti...

This paper brings some noticeable improvements to a blind decison feedback equalizer recently introduced and mainly characterized by its self-adapted structure. In its starting-up mode, this equalizer is linear and recursive and controlled by a whitening criterion for the recursive part and the Godard criterion for the transversal one. However, in the case of high order QAM signals, the whole p...

In this paper we investigate the impact of different equalization techniques for digital communication systems that employ MPSK and MQAM modulation technique to transmit information such as color image over Rayleigh fading AWGN channel. Performance is analyzed in terms of bit error rate by MATLAB simulation. For the simulation of Rayleigh fading channel the different property values such as pat...

In this paper a new Soft Input Soft Output (SISO) equalizer of linear complexity is developed. The algorithm can be used in the so-called Turbo Equalization scheme as a low cost solution in place of the Maximum A-Posteriori (MAP) equalization algorithm which has a prohibitive complexity for most real world applications. The proposed equalizer consists of two parts, namely, a Soft Interference C...

In this paper we have present performance analysis of different equalization techniques such as minimum mean– squared error (MMSE), Least mean square (LMS), Recursive Least Square (RLS) linear equalizers and MMSE-Decision Feedback equalizer (DFE), LMS-DFE, RLS-DFE non-linear equalizers in different channel conditions, in order to achieve optimal equalizer. In our simulation model we have consid...

Adaptive equalizers are used in digital communication system receivers to mitigate the effects of non-ideal channel characteristics and to obtain reliable data transmission. In this paper, we adopt least squares support vector machines (LS-SVM) for adaptive communication channel equalization. The LS-SVM involves equality instead of inequality constraints and works with a least squares cost func...

A systematic method to design power optimized FIR precoder for a special class of ISI free noise robust precoderequalizer structure is presented in this paper. The proposed equalizer has the lowest implementation complexity in theory, because the equalizer consists of a simple sampler only. It is also because of this simple equalizer, the proposed precoder-equalizer pair is robust to channel no...

A soft output low complexity maximum likelihood sequence estimation (MLSE) equalizer is proposed to equalize M-QAM signals in systems with extremely long memory. The computational complexity of the proposed equalizer is quadratic in the data block length and approximately independent of the channel memory length, due to high parallelism of its underlying Hopfield neural network structure. The s...

In this paper, a repeater system is studied which is basically used for the relay in the cellular communication. The LDPC (Low Density Parity Check) code is introduced into DFE (decision feedback equalizer) in the receiver for the BER (bit error rate) performance. For the better quality of service (QoS) and the higher convenience, the wireless repeater was considered for the relay system. In th...

We consider a time varying wireless fading channel, equalized by an LMS linear equalizer in decision directed mode (DD-LMS-LE). We study how well this equalizer tracks the optimal Wiener equalizer. Initially we study a fixed channel. For a fixed channel, we obtain the existence of DD attractors near the Wiener filter at high SNRs using an ODE (Ordinary Differential Equation) approximating the D...