Cognition radio frequency spectrum sensing method based on multi-antenna Friedman inspection

Abstract

The invention discloses a cognitive radio frequency spectrum sensing method based on multi-antenna Friedman inspection. The cognition radio frequency spectrum sensing method includes receiving radiofrequency signals with continuous time domains by a plurality of receiving antennas; carrying out down-conversion and time-domain sampling processing for the radiofrequency signals with the continuous time domains to obtain base-band signals with discrete time domains; carrying out modular operation for the base-band signals with the discrete time domains at first, and then squaring operational results to obtain instantaneous powers; comparing the instantaneous powers of the different antennas at the sampling moment in the same time domain by a Friedman inspection method; assigning numbers sequentially ranging from 1 to M to comparison results from small to large; computing a Friedman inspection statistical magnitude; and finally comparing the Friedman inspection statistical magnitude with a judgment threshold to judge whether other wireless communication services occupy a frequency band or not. Accordingly, a frequency spectrum is sensed, and a sensing performance is good. By the aid of the cognitive radio frequency spectrum sensing method, the shortcoming that noise power needs to be accurately foreseen in an existing energy detection method is overcome, and the shortcoming that frequency spectrum sensing is failed when time domain relevancy is low or time domains are irrelevant among received signals of multiple antennas in a covariance matrix detection method is also overcome.

Description

technical field [0001] The invention relates to a spectrum sensing technology in a cognitive radio system, in particular to a multi-antenna Friedman test-based cognitive radio spectrum sensing method. Background technique [0002] With the rapid growth of wireless communication services, people's demand for spectrum resources continues to increase, and the phenomenon of lack of spectrum resources becomes more and more serious. On the one hand, the rapid development of wireless communication services and the continuous emergence of various systems, protocols, and networks have made more people need to use radio spectrum; on the other hand, many frequency bands have been allocated to authorized users, and non-authorized users can only use Those frequency bands that are not authorized, and the frequency bands that are not authorized are very scarce. One of the main reasons for this phenomenon is that the existing fixed spectrum resource allocation strategy makes the utilizatio...

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Problems solved by technology

Among them, the energy detection method and the cycle feature detection method need to know the precise noise power and signal cycle feature frequency respectively in advance. When the prior information is insufficient, the perceptual performance will be greatly degraded. However, this prior information cannot be obtained in practice; in In the case of multiple antennas, the covariance matrix detection method and the eigenvalue detection method can use the time-domain correlation between the signals received by multiple antennas to realize spectrum sensing, but in practical applications, in order to obtain diversity gain, multiple antennas receive The time-domain correlation between signals is low or even irrelevant, and the covariance matrix detection method and eigenvalue detection method will fail at this time

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