A Weight Extreme Value Detection Method of Radio Frequency I/Q Data Component for Software-Defined Radio Electromagnetic Spectrum Dynamic Access Strategy

The dynamic spectrum access strategy of secondary users (SUs) of software radio can effectively improve the utilization rate of electromagnetic spectrum resources. The signal detection algorithm determines the decision standard of white space frequency band. The main prerequisite of dynamic spectrum access strategy is not to interfere with the normal wireless communication of the primary user (PU). Especially in the low signal-to-noise ratio (SNR) environment, the detection ability of weak radio signals directly affects the estimation accuracy of space electromagnetic spectrum occupancy. In this article, a radio signal detection method based on radio frequency (RF) I/Q data components is proposed to improve the detection ability of weak signals. The weight extreme value detection method of RF I/Q data component is proposed to replace the traditional energy detection (ED) method, and the boundary range of SU dynamic electromagnetic spectrum access is redefined from the perspective of radio signal coverage. When SU is dynamically connected to the electromagnetic spectrum resources, the probability of PU band interference is reduced. The software-defined radio (SDR) technology is used to extract and analyze the original RF I/Q data distribution characteristics of the target frequency band. We focus on the method of distinguishing weak signal from background noise based on components’ distribution characteristics of RF I/Q data in low SNR environment. The effective radio signal coverage criteria are defined according to the RF I/Q data distribution characteristic values of background noise. The Monte Carlo method is used to determine the decision threshold of background noise characteristic values of RF I/Q data samples in the process of analyzing data on a specific SDR hardware platform. The measured data show that the weight extreme value of RF I/Q data with background noise is larger than that of the radio signal. The fluctuation range of its weight extreme value is small. The extreme value method of RF I/Q data component weight improves the ability of radio signal detection. This method can effectively reduce the probability of PU interference during dynamic spectrum access.