基于分形相关盒维数的恒虚警检测方法

Constant False Alarm Detection Method Based on Related Box Dimension

为了提高低信噪比下频谱感知的有效性和可靠性,提出了一种基于分形相关盒维数的恒虚警检测方法。通过对信号进行自相关运算一定程度上可消除噪声的影响;对于判决门限只是凭借经验进行设定,虚警概率无法进行量化计算,通过实验拟合可知,噪声相关盒维数大致服从高斯正态分布,利用恒虚警检测可得到判决门限。仿真结果表明,基于该假设的门限值在检测概率一定的条件下,所得到的虚警概率与设定值相同,提高了感知结果的可信性;相关运算消除噪声影响,提高了信号的感知率。

To improve the credibility and effectiveness of spectrum sensing under the low signal to noise rate, this paper presents a CFAR （constant false alarm） detection method based on fractional related box dimension. The influence of the noise can be weakened by the related operation of the signal. Because the threshold main- ly is set only by our experience, the probability of false-alarm could not be calculated. By the experiment fit- ting, we can know the box dimension of noise basically obeys the Gaussian distribution. The threshold by the constant false alarm detection can be gotten. Simulation results show that by the threshold based on the constant false alarm detection can a same probability of false-alarm as that we set be gotten. The related operation weakens the influence of the noise. This method improves the credibility of spectrum sensing and the possibili- ty of detection of the algorithm.