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Modulation identification and blind pseudo-code sequence estimation of MC-CDMA signals

A technology of MC-CDMA and MC-DS-CDMA is applied in the field of blind estimation of pseudo-code sequences to achieve the effect of improving anti-noise performance.

Inactive Publication Date: 2016-08-17
CHONGQING UNIV OF POSTS & TELECOMM
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Problems solved by technology

[0004] At present, the research on MC-CDMA signals mainly focuses on channel estimation, frequency offset, or bit error performance analysis, involving modulation identification and pseudo code sequence estimation of MC-CDMA signals, and there are few related literatures at home and abroad.

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  • Modulation identification and blind pseudo-code sequence estimation of MC-CDMA signals
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  • Modulation identification and blind pseudo-code sequence estimation of MC-CDMA signals

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[0020] The implementation of the present invention will be further described below in conjunction with the accompanying drawings and specific examples.

[0021] figure 1 Shown is the flow chart of MC-CDMA signal modulation identification and pseudo code sequence blind estimation in the present invention. Specific steps: after synchronously demodulating the received signal (the frequency of the subcarrier has been estimated), use the existing cyclic autocorrelation algorithm to estimate the symbol length, useful symbol length and other parameters, and then remove the cyclic prefix. Then construct a matrix with the number of subcarriers as rows and integer multiples of the number of subcarriers as columns, and perform FFT transformation on each column of the matrix. Then construct the signal matrix and perform singular value decomposition on it. According to theoretical analysis, if the number of the largest non-zero singular value is 1 (that is, the rank of the matrix is ​​1 w...

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Abstract

The invention claims a singular value decomposition-based MC-CDMA signal modulation identification and pseudo-code sequence estimation method, which belongs to the technical field of signal processing. By removing the cyclic prefix first, then constructing the matrix and performing singular value decomposition on it, the signal categories can be distinguished according to the number of eigenvalues. Since the number of eigenvalues ​​of a single-user MC-CDMA signal is always 1, it has nothing to do with the size of the construction matrix, so it is easy to distinguish from it. In the case of known prior information such as modulation type and pseudo-code period, the pseudo-code sequence is estimated by the left singular vector. For complex problems such as classifier design, the algorithm has the advantage of less calculation for the estimation of pseudocode sequences. The method can effectively distinguish MC-CDMA and MC-DS-CDMA signals, and at the same time blindly estimate the pseudo-code sequence of the MC-CDMA signal, which is of great significance for the subsequent processing of the signal and the analysis of subtle features.

Description

technical field [0001] The invention relates to communication signal processing, in particular to modulation identification of multi-carrier CDMA signals (MC-CDMA and MC-DS-CDMA signals) based on singular value decomposition, and blind estimation of pseudocode sequences of MC-CDMA signals. Background technique [0002] Multi-carrier CDMA, which combines CDMA and OFDM technology, fully retains their respective advantages, and has the advantages of low interception rate, strong anti-fading ability, high spectrum utilization rate, high data transmission efficiency and good code division multiple access capability. These multi-carrier signals are easily generated and recovered using Fast Fourier Transform (FFT) and Inverse Fast Fourier Transform (IFFT) at the transmitter and receiver, respectively, reducing the complexity of the transmitter and receiver. There are three forms of multi-carrier CDMA: multi-carrier code division multiple access (MC-CDMA), multi-carrier direct sprea...

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Application Information

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IPC IPC(8): H04L27/00H04L27/26H04J13/00
CPCH04L27/0012H04J13/0022H04L27/2695
Inventor 张天骐钱文瑞张刚罗忠涛
Owner CHONGQING UNIV OF POSTS & TELECOMM
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