  Spectrum sensing technology is a crucial aspect of modern communication
technology, serving as one of the essential techniques for efficiently
utilizing scarce information resources in tight frequency bands. This paper
first introduces three common logical circuit decision criteria in hard
decisions and analyzes their decision rigor. Building upon hard decisions, the
paper further introduces a method for multi-user spectrum sensing based on soft
decisions. Then the paper simulates the false alarm probability and detection
probability curves corresponding to the three criteria. The simulated results
of multi-user collaborative sensing indicate that the simulation process
significantly reduces false alarm probability and enhances detection
probability. This approach effectively detects spectrum resources unoccupied
during idle periods, leveraging the concept of time-division multiplexing and
rationalizing the redistribution of information resources. The entire
computation process relies on the calculation principles of power spectral
density in communication theory, involving threshold decision detection for
noise power and the sum of noise and signal power. It provides a secondary
decision detection, reflecting the perceptual decision performance of logical
detection methods with relative accuracy.
