Variable Step Size Blind Equalization Based on Sign Gradient Algorithm
نویسندگان
چکیده
This work proposes a variable step size sign gradient algorithm to solve the problem of blind equalization under impulse noise environment. This algorithm suppresses the impulse noise interference effectively because of the sign operation on the instantaneous gradient based on constant modulus algorithm (CMA) cost function. Meanwhile, the excess mean square error can be further reduced by use of a variable step size algorithm based on the iterative times and the reliability of the output signal. Simulation results show that, the variable step size blind equalization based on sign gradient algorithm has the fastest convergence rate and the lowest steady state residue error compared with the fractional low order CMA, the nonlinear transform CMA and stop-and-go CMA.
منابع مشابه
Blind Equalization Based on Direction Gradient Algorithm under Impulse Noise Environment
A new constant modulus blind equalization based on direction gradient algorithm was proposed, which can obtain robust convergence performance under impulse noise environment. The impulse noise has no more than two order moments, so constant modulus algorithm (CMA) based on stochastic gradient descent algorithm is often ill-convergence or divergence. The direction gradient algorithm uses the rel...
متن کاملA Novel Variable Step Size Adjustment Method Based on Autocorrelation of Error Signal for the Constant Modulus Blind Equalization Algorithm
Blind equalization is a technique for adaptive equalization of a communication channel without the use of training sequence. Although the constant modulus algorithm (CMA) is one of the most popular adaptive blind equalization algorithms, because of using fixed step size it suffers from slow convergence rate. A novel enhanced variable step size CMA algorithm (VSS-CMA) based on autocorrelation of...
متن کاملImproved Blind Equalization Scheme Using Variable Step Size Constant Modulus Algorithm
The blind equalizer relies on the knowledge of signal’s constellation and its statistics to perform equalization. The major drawback is that the blind equalizer will typically take a longer time to converge as compared to a trained equalizer. Variable Step-Size LMS (VSLMS) algorithms have been introduced to optimize the speed and steady-state error. The relationships between the a priori and a ...
متن کاملSquare contour algorithm for blind equalization of QAM signals
A new distance-adjusted approach is proposed in which static square contours are defined around an estimated symbol in a QAM constellation, which create regions that correspond to fixed step sizes and weighting factors. As a result, the equalizer tap adjustment consists of a linearly weighted sum of adaptation criteria that is scaled by a variable step size. This approach is the basis of two ne...
متن کاملImproving the Rate of Convergence of Blind Adaptive Equalization for Fast Varying Digital Communication Systems
The recent digital transmission systems impose the application of channel equalizers with bandwidth efficiency, which mitigates the bottleneck of intersymbol interference for high-speed data transmission-over communication channels. This leads to the exploration of blind equalization techniques that do not require the use of a training sequence. Blind equalization techniques however suffer from...
متن کامل