Method and system for acquiring cyclic spectrum alpha section based on frequency domain smoothing

A cyclic spectrum and smoothing technology, which is applied in the field of obtaining cyclic spectrum α-section based on frequency domain smoothing, can solve problems such as the inability to obtain odd-numbered position spectrum information, the inability to meet the needs of parameter extraction, modulation mode identification signal processing, etc., to reduce The effect of α-section spectral information loss and spectral information integrity

CN101917239AInactive Publication Date: 2010-12-15THE PLA INFORMATION ENG UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2010-12-15
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a method for acquiring a cyclic spectrum alpha section based on frequency domain smoothing. The method comprises the following steps of: setting a certain time length for the received signal to perform discrete Fourier transform (DFT); and fixing a Fourier frequency value k, utilizing the calculating result of the discrete Fourier transform, setting a value of a cyclic frequency variable alpha as m1+m2 and selecting two smoothing windows to perform cross transposition and performing frequency domain smoothing calculation to acquire the cyclic spectrum alpha section corresponding to the cyclic frequency variable alpha, wherein the centers of the two smoothing windows are k+m1 and k-m2 respectively and the lengths of the two smoothing windows are 2M+1. In the method,the cyclic spectrum alpha section is acquired through the cross transposition of the two smoothing windows in the frequency domain, the spectrum information at the odd number position of the section can be effectively recovered, so that the spectrum information of the odd position in the cross section can be effectively restored, alpha section spectrum information loss caused by a DFT barrier effect can be reduced, the spectrum information of the acquired cyclic spectrum alpha section is more complete, and the requirements of subsequent signal processing processes, such as parameter extraction, modulation mode identification and the like, can be met.
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Description

Technical field

[0001] The present invention relates to the technical field of electromagnetic spectrum detection in a cognitive radio system, and more specifically to a method and system for obtaining a cross-section of a cyclic spectrum based on frequency domain smoothing. Background technique

[0002] With the continuous development of communication technology, as a more mature communication technology, cognitive radio technology has been widely used. In cognitive radio systems, signals with periodic or multi-period steady changes in statistical characteristics are generally collectively referred to as cyclostationary or cyclostationary signals, which are also one of the main forms of radio signals.

[0003] In cognitive radio systems, the processing of radio signals usually mainly includes signal detection, parameter estimation, and modulation recognition. At present, cyclic spectrum theory is one of the main methods to study and analyze periodic stationary signals. Cyclic sp...

Examples

Embodiment Construction

[0030] The core idea of ​​the present invention is to adopt the cross-shifting method of two smoothing windows to provide a new method for obtaining the cyclic spectrum α section based on frequency domain smoothing, which can effectively reduce the cyclic spectrum section characteristics caused by the discrete Fourier transform fence effect The loss of information can obtain more obvious and stable cyclic spectrum α cross-sections with characteristic information, provide a reliable basis for further signal processing, and improve the performance of parameter estimation and modulation recognition.

[0031] The method for obtaining a cyclic spectrum α section based on frequency domain smoothing provided by the embodiment of the present invention may include the following steps:

[0032] Step 1: Set a certain duration on the received signal to perform discrete Fourier transform.

[0033] For the received signal x(n), a certain duration Δt=NT can be selected s ,Using formula (1) to perfo...