Blind equalization method for wavelet neural network based on space diversity

Abstract

The invention discloses a blind equalization method for a wavelet neural network based on space diversity. On the basis of analysis of a space diversity technology and the equalization performance of a wavelet neural network, the method reduces the influence of fading by utilizing the space diversity and overcomes intersymobl interferences by using the stronger approximation capacity of a blind equalizer of the wavelet neural network. The invention overcomes the intersymobl interferences caused by the multipath propagation and the fading characteristic of a channel at a receiving end, improves the communication quality and has high convergence speed and small mean square error. The effectiveness of the method is verified by an acoustic channel simulation result. The method can effectivelyrealize the separation of signals and noise and the real-time restoration of the signals.

Description

technical field [0001] The invention relates to a wavelet neural network blind equalization method based on space diversity, and belongs to the technical field of blind equalization methods for overcoming inter-symbol interference (Inter-Symbol Interference, ISI) caused by multipath fading of underwater acoustic channels. Background technique [0002] In the underwater communication system, inter-symbol interference (ISI) caused by multipath fading and channel distortion distorts the transmitted signal and generates bit errors at the receiving end, which seriously affects the communication quality. An effective means to reduce intersymbol interference is to use equalization technology. Since the equalization itself can be regarded as a pattern classification problem, and the neural network has good pattern classification characteristics, it is worth studying to design a blind equalizer with a neural network (see literature [1] CHENG Hai-qing, ZHANG Li-yi. Blind Equalization...

AI Technical Summary

Problems solved by technology

Traditional equalization techniques need to periodically send training sequences, which wastes limited bandwidth resources. Blind equalization techniques that do not need to send known training sequences can save bandwidth and improve communication efficiency.

Through equalization technology, an equalizer that is completely opposite to the channel characteristics can be designed to offset the influence of channel distortion (see literature: [3] E.G.Larsson, On the combination of spatial diversity and multi-user diversity [J]. IEEECommunications Letters, 2004, 8: 517-519), but the traditional blind equalization method is researched on a single channel, and the new generation of high-speed underwater communication system will adopt the method based on multipath equalization, so the emergence of diversity technology is a blind The design of the equalizer proposes a new idea (see literature: [4] Sung-Hoon Moon, Ju-Yeun Kim and Dong-Seog. Han. Spatial diversity technique for Improvement of DTV reception performance [J]. IEEE Transactions on consumer electronics , 2003, 49(4): 958~964)

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