Method for estimating signal-to-noise ratio of time-frequency overlapped signals in cognitive radio

Abstract

The invention discloses a method for estimating the signal-to-noise ratio of time-frequency overlapped signals in cognitive radio. The method includes the following steps that: a normalized higher-order cumulant equation is constructed according to the normalized higher-order cumulant of received signals; all component signal modulation type combinations are traversed, the power of component signals is calculated through the normalized higher-order cumulant equation, and whether the modulation type combinations are correct is judged; and correct component signal modulation type combinations and power are obtained, the noise power of the time-frequency overlapped signals is calculated, so that the signal-to-noise ratio of the time-frequency overlapped signals in the underlay cognitive radio can be estimated. According to method, the normalized mean square error of the estimation of the signal-to-noise ratio is smaller than 0.2 under a high spectrum overlap rate when a signal-to-noise ratio is 0dB. The method has excellent performance in the estimation of the signal-to-noise ratio of the time-frequency overlapped signals in the underlay cognitive radio. With the method of the invention adopted, the measurement of interference temperature can be facilitated, primary users and secondary users can coexist under the interference temperature, and therefore, spectrum efficiency can be improved.

Description

technical field [0001] The invention belongs to the technical field of communication, and in particular relates to a signal-to-noise ratio estimation method of a time-frequency overlapping signal in an underlay cognitive radio. Background technique [0002] In the field of modern wireless communication, with the development of communication technology, spectrum resources become more and more tight. The underlay cognitive radio method can enable primary users and secondary users to share the same frequency band, which is an effective way to solve the problem of spectrum resource shortage. In the underlay mode, the secondary user may be accessed only when the interference temperature of the signal in the authorized channel is lower than the interference temperature limit of the channel. At this time, the power of the time-frequency overlapping signal in the channel is an important parameter to calculate the interference temperature, and the calculated signal power can be obta...

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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for estimating the signal-to-noise ratio of time-frequency overlapping signals in cognitive radio, aiming to solve the problem that the signal-to-noise ratio of time-frequency overlapping signals is difficult to estimate in the underlay spectrum sharing mode

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