OFDM signal spectrum sensing method for time synchronization and frequency offset

Abstract

The invention discloses an OFDM signal spectrum sensing method for time synchronization in the presence of frequency offset. The method comprises the following steps: sampling a received signal from a monitoring channel to obtain a sampling signal; then estimating noise power via the autocorrelation of a cyclic prefix of an OFDM signal in the received signal according to the sampling values of all sampling points in the sampling signal under the condition of time synchronization and in the presence of frequency offset; calculating a covariance matrix of the sampling signal according to the sampling values of all sampling points in the sampling signal; then calculating test statistics according to the noise power and the covariance matrix of the sampling signal; and finally, comparing the test statistics with an obtained judgment threshold to judge whether an authorized user signal exists in the monitoring channel so as to realize spectrum sensing. The OFDM signal spectrum sensing method has the advantages of effectively improving the spectrum sensing performance of the OFDM signal and ensuring low computation complexity.

Description

technical field [0001] The present invention relates to a spectrum sensing method in a cognitive radio system, in particular to a noise power estimation-based OFDM signal spectrum sensing method for time synchronization and frequency offset. Background technique [0002] The limited availability of physical spectrum resources, the rapid development of wireless communication technology and the substantial increase in people's demand for data rates constitute a major obstacle to the development of today's wireless communication field. However, a large number of studies have shown that because the current government adopts a fixed spectrum allocation strategy, many allocated spectrums have not been fully utilized. In order to improve these frequency bands that have been allocated but underutilized, cognitive radio technology provides a feasible solution. Cognitive radio technology enables wireless devices to interact with their communication environment and change their own tr...

AI Technical Summary

Problems solved by technology

The covariance matrix-based spectrum sensing method proposed by Zeng et al. in "Spectrum sensing algorithms for cognitive radio based on statistical covariance (spectrum sensing method based on statistical covariance in cognitive radio)" in 2009 can utilize the Correlation realizes spectrum sensing, which has the characteristics of low calculation amount, but this method does not consider the specific situation of time synchronization and frequency offset, so it cannot effectively use the cyclic prefix autocorrelation characteristic of OFDM signal

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