Compressed Sensing Time Domain Channel Estimation Method Based on Wavelet Transform Modulation System

Abstract

The invention discloses a compressed sensing time-domain channel estimation method for a wavelet transform modulation system. The method comprises the steps of selecting a suitable wavelet base function based on a channel estimation condition, adopting time-domain block-type pilot insertion, performing IDWT on a signal to finish modulation, building a measurement matrix by adopting a standard Toeplitz matrix, performing time-domain channel estimation by using a compressed sensing technology, and adopting Fourier transform after channel impulse response estimation to simplify a channel solutionprocess. For a wavelet transform modulation system, ICI (Inter-Carrier Interference) and ISI (Inter-Symbol Interference) of each sub-channel can be removed efficiently by utilizing the wavelet base function, and the channel estimation accuracy is improved; the number of measurement values required by channel estimation is reduced by adopting the compressed sensing time-domain channel estimation,and the calculation complexity and cost are reduced; the data signal part is solved by adopting the FFT, so that massive operation caused by wavelet change is avoided, limitations caused by wavelet transform is overcome, and the wavelet transform modulation system is enabled to have a wider application scope.

Description

technical field [0001] The invention relates to a high-precision and low-complexity channel estimation method in the time domain based on a wavelet transform modulation system proposed for a frequency-selective fading environment and using a compressed sensing technology. Background technique [0002] In LTE and 4G systems, we use multi-carrier modulation based on Orthogonal Frequency Division Multiplexing (OFDM) technology, which has the advantages of high spectrum utilization and the use of IFFT and FFT to realize modulation and demodulation systems , Effectively resist Inter-carrier Interference (ICI) and Inter-symbol Interference (Inter-symbol Interference, ISI), but there are also some shortcomings, such as being easily affected by frequency deviation, which will make the regularity between subcarriers Intercourse is destroyed, resulting in ICI; it is necessary to insert guard intervals and cyclic prefixes to eliminate ISI and ICI, and reduce spectrum utilization. The ...

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Problems solved by technology

[0005] The present invention proposes a time-domain channel estimation method for wavelet transform modulation systems, which solves the traditional channel estimation problem of constrained wavelet modulation applied in communication systems. Since the orthogonal wavelet basis functions have non-zero translation self-orthogonality and The orthogonality between the wavelet function bases can effectively eliminate the interference ICI and ISI of each sub-channel, can save the cyclic prefix, and improve the spectrum utilization rate; the use of time domain pilot insertion is beneficial to resist frequency selective fading. The technical solution adopted includes the following steps:

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