Blind Equalization Algorithm For Multi-user MIMO Systems

In recent years, the demand of wireless communication data traffic has been increased, it accelerate the evolution and application of the broadband wireless communication technical, so people take more and more attention on multi-user Multiple Input Multiple Output (Multiple-Input Multiple Output, MIMO) wireless systems in the signal processing technology. In order to remove inter-symbol interference, the blind equalization technique is always used, this text firstly studies the mode of single-user MIMO system and multi-user MIMO system channel and the capacity of the channel, then studies the single-user MIMO system norm blind equalization algorithm, the wavelet theory is used to reduce the autocorrelation of the input signals and increase the performance of the algorithm, Finally studies the orthogonal wavelet blind equalization technology in the application of the multi-user MIMO system.The main contributions are as follows:1Blind Equalization Algorithm Based on the Orthogonal Wavelet Transform for SIMO SystemsIn order to improve the anti-fading and constant modulus blind equalization algorithm performance of SIMO system. A blind equalization algorithm based on the orthogonal wavelet transform for Simple-Input Multiple-Output system is proposed, the signals can be equalized in wavelet transform domain. The wavelet transform is used to reduce the autocorrelation of the input signals. After the analysis and computer simulation, it can be seen that this algorithm has better performance than CMA in SIMO system.2The norm blind equalization algorithm based on SVD of single-user MIMO systemIn a single-user MIMO system, the channel cannot be equalization if the output signals load into equalizer directly. Based on the matrix singular value theory as the mathematical basis, norm of blind equalization algorithm combined with singular value decomposition theory. The received signals are transformed into an orthogonal signal subspace, after the wavelet transform, then via the channel of blind equalization. Based on the norm blind equalization algorithm of SIMO systems, propose a wavelet blind equalization algorithm for MIMO system based on SVD.3MIMO system based wavelet blind equalization algorithm Because of the complexity of the multiuser Multiple-Input Multiple-Output (MIMO) wireless communication system. The theory of this research is very scarce. Multi-user multiple input multiple output (MIMO) communication system is not only affected by inter symbol interference caused by multipath effect and frequency selective fading channel, the signal interference between different users seriously affect communication effect. In order to improve the performance of the system, this article is based on the study of single-user MIMO system blind equalization algorithm, using the theory of singular value decomposition, the multi-user MIMO system is decomposed into several parallel independent channel, channel again separately for each individual channel equalization, the success of wavelet blind equalization algorithm is applied to multi-user MIMO system. Theoretical analysis and computer simulation results show that the algorithm can achieve faster convergence speed and low steady-state error, and the eye diagram after convergence is relatively clear, all these prove the feasibility and effectiveness of this method.