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

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.

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...

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Problems solved by technology

[0013] In view of this, the present invention is to provide a method and system for obtaining the α-section of the cyclic spectrum based on frequency-domain smoothing, so as to solve the problem that the prior art cannot obtain the spectrum information of odd positions, so that subsequent signal processing such as parameter extraction and modulation identification cannot be satisfied. For the problem of process requirements, the technical solution is as follows:

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