Wavelet weighted multi-mode blind equalization method based on chaos optimization of support vector machine

Abstract

The invention discloses a wavelet weighted multi-mode blind equalization method based on the chaos optimization of a support vector machine. The method comprises the following steps of: operating a complex signal source transmission signal by using a pulse response channel, and thus obtaining a channel output vector; summating a channel noise and the channel output vector, and thus obtaining an input signal of an orthogonal wavelet transformer; performing orthogonal wavelet transformation on the input signal of an equalizer, and thus obtaining the input signal of the equalizer; operating the input signal of the equalizer by using the equalizer, and thus obtaining an output signal of the equalizer; and operating the output signal of the equalizer by using a judger, and updating the weight vector of the equalizer by using a weighted multi-mode blind equalization method. The method has the advantages that: by using the support vector machine, the weight vector of the wavelet weighted multi-mode blind equalization method is initialized; a convergence speed can be improved, and the immergence of a local minimal value point is avoided; parameters of the support vector machine are selected for parameter combined optimization; combined optimization target functions are established; the optimum target function value is searched by chaos optimization; and the fitting capacity of the support vector machine is improved.

Description

technical field [0001] The invention relates to a wavelet weighted multi-mode blind equalization method based on chaos support vector machine optimization in an underwater acoustic channel. Background technique [0002] In the underwater acoustic channel, the limited channel bandwidth and multipath propagation lead to intersymbol interference, resulting in bit errors in received data, which affects the quality of the communication system. In order to improve the frequency band utilization of the channel, high-order QAM modulation is often used. In order to overcome inter-symbol interference, equalization technology needs to be introduced at the receiving end. Blind equalization technology is widely used because it does not need to send training sequences. [0003] Among the existing blind equalization methods, the constant modulus algorithm (Constant Modulus Algorithm, CMA) has a simple structure, a small amount of calculation, and good stability, and is widely used (see lit...

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Problems solved by technology

Literature (see literature [2] Yang J, Werner J J, and Dumont G A. The multiple modulus blind equalization and its generalized algorithm. IEEE Journal on Sel. Area in Commun., 2002, 20(5): 997-1015) The multi-mode blind equalization method (Multiple Modulus Algorithm, MMA) uses the amplitude and phase information of the equalizer output signal to improve the steady-state convergence performance, but the in-phase and quadrature components of the weight vector in MMA use a single decision The circle is adjusted. With the increase of the QAM order, the performance of channel equalization becomes worse, and the convergence speed and mean square error cannot achieve the ideal effect.

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