Improved double-threshold cooperative spectrum sensing method

The invention relates to an improved double-threshold cooperative spectrum sensing method, which comprises the following steps that: a cognitive user in a cognitive radio system senses a local spectrum, compares and classifies sensed main user energy values, if the energy values are beyond two thresholds, can directly perform local judgment to obtain a hard judgment result whether a main user exists and send the result to a fusion center, if the energy values are between the two thresholds, the cognitive user needs to send the sensed main user energy values and signal to noise ratios to the fusion center, and the fusion center calculates a weight factor of each cognitive user according to the received signal to noise ratios and performs fusion judgment according to the received energy values to obtain a soft judgment result whether the main user exists; and the fusion center comprehensively processes the hard judgment result and the soft judgment result, and makes a final judgment whether the main user exists by using an 'or' rule. According to the method, the advantage of double-threshold cooperative spectrum sensing can be fully realized; and the spectrum sensing performance is improved.