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认知无线电频谱检测中能量检测算法在低信噪比下检测效率低,而似然比检测(LRT)算法复杂度过高.对此,首先在低信噪比下对LRT算法进行了化简,并给出了化简LRT算法性能参数的闭合表达式;提出了一种联合检测算法,在低信噪比条件下采用能量与简化LRT二次检测,在其他条件下则采用能量检测.理论分析和仿真结果均表明,所提算法在低信噪比下能对主用户信号有效检测,且实现复杂度低,检测性能优于LRT算法.
In the cognitive radio spectrum detection, the energy detection algorithm has low detection efficiency at low signal-to-noise ratio (SNR), and LRT algorithm is too complex. In this case, the LRT algorithm is first reduced at low SNR , And gives a closed expression of the performance parameters of reduced LRT algorithm. A joint detection algorithm is proposed, which uses energy and simplified LRT quadratic detection under low signal-to-noise ratio and energy detection under other conditions. The analysis and simulation results show that the proposed algorithm can effectively detect the main user signal under low signal-to-noise ratio, and the implementation complexity is low and the detection performance is better than the LRT algorithm.