Abstract: Because the eigenvalue-based double thresholds spectrum sensing algorithms overlook the reliability differencebetween second users(SU) and the highexpense of fusion decisions,a double thresholds DMM cooperative spectrum sensing algorithm based on credibility(DT-CDMM) was proposed to improve the sensing performance.Based on the difference between maximum and minimum eigenvalue(DMM) algorithm,a double thresholds DMM spectrum sensing algorithm based on limiting eigenvalue distribution is used as SU’s local sensing,a triggered mechanism combined with soft and hard decisions is established to cut the system expenses,the final decision is obtained via the weighting of SU’ssensing performance and local credibility,and a self-adaption compensation for hard decisions is applied.Theory analysis and simulations show that the DT-CDMMimproves the probability of multi-user collaborative detection compared with double eigenvalue thresholds algorithms and double thresholds energy detection algorithm when noise is undefined.

Key words: Cooperative spectrum sensing, Credibility, DMM, Eigenvalue, Limiting eigenvalue distribution