作为认知无线电的关键技术之一, 频谱感知通过实时感知电磁环境以检验授权用户频谱和可用频谱空穴。低轨卫星地球站是典型的单用户感知节点, 具有地理位置及频谱环境相对固定的特点, 但是, 随其天线仰角变化, 其接收信号信噪比并不固定。为了提高卫星地球站频谱利用效率, 需要感知地球站周边频谱环境, 根据多分辨率检测算法检测速度快、匹配滤波器检测算法检测概率高的特点, 设计了一种基于多分辨率检测和匹配滤波器检测结合的两步检测算法。通过理论分析和实验仿真表明, 与能量检测相比, 两步检测的检测时间缩短, 同时检测的准确性得到了提高。

As one of the critical technology of cognitive radio, spectrum sensing detects the surrounding electromagnetic environment in real-time to make sure whether ‘spectrum hole’ exists and primary users’ spectrum. Low earth orbit (LEO) satellite earth station is a kind of typical single user perception nodes, and it has the characteristics of fixed geographical location and spectrum environment. However, with its antenna elevation changing, the received signal SNR is not fixed. The spectrum environment around the earth station needs to be sensed for improving the spectrum utilization efficiency of satellite earth station. According to the characteristics of multi-resolution detection algorithm with fast detection speed and matched filter detection algorithm with high detection probability, a two-step detection algorithm is designed based on the corporation of multi-resolution detection and matched filter detection. Through theoretical analysis and experimental simulation and comparing with energy detection, this method shortens the detection time and improves the accuracy of detection.