SNR Estimation Method of Time-Frequency Overlapped OFDM Signal in Spectrum Sharing Mode

Abstract

The invention belongs to the technical field of communication, and discloses a signal-to-noise ratio estimating method of time frequency overlapping OFDM signals under a frequency spectrum sharing mode. The method comprises the steps of firstly computing a cyclic autocorrelation function of received time frequency overlapping OFDM signals, capturing a cross section in which delay is less than chip time when oversampling ratios of component signals are equal or unequal, and then estimating overall power of the component OFDM signals by extracting a discrete spectrum line from the cross section; and at last estimating the overall power of the received signals according to values of the cyclic autocorrelation function when both the delay and cycle frequency are zero, thus estimating a signal-to-noise ratio of the time frequency overlapping OFDM signals. According to the method provided by the invention, the signal-to-noise ratio of the time frequency overlapping OFDM signals can be effectively estimated; not only the signal-to-noise ratio of the time frequency overlapping OFDM signals can be estimated, but also prior parameters such as the oversampling ratio and the chip time of the component signals can also be estimated.

Description

technical field [0001] The invention belongs to the technical field of communication, in particular to a method for estimating the signal-to-noise ratio of a time-frequency overlapping OFDM signal in a spectrum sharing mode. Background technique [0002] Underlay spectrum sharing technology improves spectrum utilization by sharing spectrum resources between primary users and secondary users, and has gradually become a hot spot in cognitive radio research. Orthogonal Frequency Division Multiplexing (OFDM) technology is widely used in cognitive radio because of its efficient spectrum utilization and anti-fading performance. In underlay cognitive OFDM, when the secondary user does not exceed the interference temperature of the primary user, it can share spectrum resources with the primary user at the same time, and the signal in the frequency band is an OFDM signal with time-frequency overlap, where the interference temperature measurement is the underlay cognitive One of the ...

AI Technical Summary

Problems solved by technology

[0003] To sum up, the problem existing in the existing technology is: due to the coexistence of the primary user and multiple secondary users, which overlap in the time domain and frequency domain, it is impossible to directly process the signal from the time domain, frequency domain or space domain to perform signal-to-noise ratio analysis. Therefore, the existing technology cannot estimate the signal-to-noise ratio of time-frequency overlapping OFDM signals in underlay cognitive radio

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