Wavelet Blind Equalization Algorithm Based Different Error Function And Simulation On DSP

In underwater acoustic communication system, the Inter-Symbol Interference (ISI), caused by multi-path effects and bandwidth limited channels, affect the performance of communication seriously. Blind equalization operating without the aid of a training sequence can equalize channels using statistic characteristic of received signal to reduce or eliminate ISI, so utilization quotiety of bandwidth is improved greatly and blind equalization become study topic. With the rapid development of wavelet transform theory, a new way is supplied for transform domain blind equalization algorithm study. Autocorrelation of input signal various components can be reduced effectively after orthogonal wavelet transform, and the convergence rate of equalization algorithm can be speeded up effectively. Error function is a part of updating, so if error function is different, equalizer weight vector is also different. Better characteristic error functions are need to design equalizer. Wavelet blind equalization algorithm based different error function and simulation on DSP is deep studied in this dissertation. The main contributions are as follows:1 Correlation Function based the Blind Equalization Algorithm and simulation on DSPCorrelation function is introduced to blind equalization algorithm in this paper, directly processing correlation function of the input signal, a new error function is defined, correlation function based the blind equalization algorithm is proposed. The algorithm is derived according to correlation function mean square error criteria defined by Asharif and Newton's instantaneous gradient descent algorithm, at the same time correlation ratio coefficient is introduced and used to adjust the equalizer weight vector. MATLAB simulation tests with underwater acoustic channel and DSP the simulation implecation to proposed algorithm.2 Orthogonal Wavelet Transform based Odd Symmetry Error function blind equalization algorithmAfter analyzing the factors affected the performance of blind equalization, we knowed that the equalizer input signal's autocorrelation is one of the important factors which affect the convergence rate. The autocorrelation of signal various components can be effictively reduced after orthogonal wavelet transform (WT) and being normalizated the energy in wavelet transform domian, and the convergence rate of equalization algorithm can be speeded up effectively. And odd symmetry characteristics of error function can reduced mean square error of equlizer. Hence, orthogonal wavelet transform based odd symmetry error function blind equalization algorithm (WT-OSE) is proposed after combining wavelet transform with odd symmetry error function, The efficiency of the proposed algorithm is proved by simulation in underwater acoustic channel, meanwhile DSP simulation implecation to proposed algorithm.3 Orthogonal Wavelet Packet Transform based Variable step-size Dual-Model blind equalization Algorithm and simulation on DSPComparing with orthogonal wavelet transform, the autocorrelation of input signal is futher reduced via the signal scale space and wavelet space are decomposed respectively by orthogonal wavelet packet transform (WPT). Hence, orthogonal wavelet packet transform based variable step-size dual-mode blind equalization algorithm (WPT-VDMA) is proposed, after combining WPT with decision directed (DD), The efficiency of the proposed algorithm is proved by MATLAB and DSP simulation in underwater acoustic channel.4 Orthogonal Wavelet Transform based Double-error function blind equalization Optimization algorithm and simulation on DSPWavelet transform and normalizating energy to input of equalizer is effective way that improves convergence rate of equalizer. And momentum algorithm can also improves convergence rate of equalizer. Error function is an important factor that affects residual error of equalizer, studies have shown that if error function is different the performance of equalizer. Momentum algorithm and wavelet transform are introduced into decision feedback constant modulus blind equalization algorithm(DFE), four combinations of hyperbolic tangent error function and constant modulus error function are used to adjust separately weight coefficient of forward equalizer and the feedback equalizer in the algorithm, orthogonal wavelet transform based double-error function momentum decision feedback constant modulus blind equalization algorithm (WT-DMCMA-DFE) is proposed and MATLAB and DSP simulation is done.Figure [47] Table [10] Reference [94]...