Wavelet constant modulus blind equalization method in MIMO (Multiple Input Multiple Output) system

Abstract

The invention discloses a wavelet constant modulus blind equalization method in a MIMO (Multiple Input Multiple Output) system from the aspect of reducing?inter channel?and inter signal?correlation, so as to overcome defects that the traditional constant modulus blind equalization method in the MIMO system is weak in inter channel interference inhibition ability, slow in the convergence rate and large in steady-state errors. According to the method, singular value decomposition is used for reducing the correlation of channel output signals; an orthogonal wavelet base function is used for carrying out orthogonal wavelet transformation on MIMO channel output signals and autocorrelation of input signals of a blind equalizer is reduced; on the basis of fully considering the inter channel correlation, a cost function of MIMO system constant modulus blind equalization algorithm is redefined, and cross-correlation of output signals of the blind equalizer is reduced; and a variable step size function is used for controlling a blind equalization?weight vector?updating process, the convergence rate quickened, and the steady-state errors are reduced.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to an improved wavelet normal mode blind equalization method for a multiple-input multiple-output MIMO system. Background technique [0002] In order to meet the large-capacity and high-speed requirements of future mobile communication systems and improve spectrum utilization, multiple-input multiple-output (MIMO) systems with multiple antennas for transmission and reception have become a hot research topic in the field of communications. In a MIMO system, limited channel bandwidth, Inter-symbol Interference (ISI) and Inter-channel Interference (ICI) have important impacts on communication efficiency and communication quality. Research shows that introducing blind equalization technology at the receiving end is an effective way to suppress ISI and ICI and improve channel bandwidth utilization. However, in the traditional normal mode blind equalization technology o...

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Problems solved by technology

[0032] Aiming at the shortcomings of the traditional norm blind equalization method for MIMO systems, such as weak ability to suppress inter-channel interference, slow convergence speed, and large steady-state error, through experiments and analysis, we found that the root causes are: (1) They are based on the traditional norm The cost function obtains the weight vector update process, the correlation between MIMO channels is not considered in this traditional normal cost function; (2) measures to reduce the correlation between signals are not considered

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