认知对流层散射通信中的频谱感知

Spectrum Sensing in Cognitive Troposcatter Communications

认知对流层散射通信是解决现阶段对流层散射通信系统频段拥挤、共道干扰和容量与带宽矛盾的有效手段。而频谱感知技术作为认知对流层散射通信的核心,能够给认知用户提供特定频段的频谱信息,为及时规避干扰和利用空闲频带提供依据。针对认知对流层散射通信中的频谱感知问题,在能量检测方法的基础上,研究了AWGN和Nakagami-m信道条件下的频谱检测问题,推导出AWGN信道下和Nakagami-m信道下基于最大比合并的检测概率的精确表达式,并进行仿真分析。结果表明散射天线的离轴角越大,检测性能越差,且基于分集合并的频谱感知在对衰落信道信号的检测性能相较于无分集有较大优势。

The cognitive troposcatter communications is a potential technology to deal with the problems of spectrum congestion,co-channel interference and conflict between capacity and bandwidth in the current troposcatter communication system. As a key technique of cognitive troposcatter communications,the spectrum sensing can provide terminal users with the spectrum data of the given frequency band,and give the basis for prompt avoidance of interference and idle frequency band utilization. Aiming at the spectrum sensing in troposcatter communications,this paper studies the spectrum detection over AWGN and Nakagami-m channels based on energy detection method. The exact expression of detection probability over AWGN channel,as well as Nakagami-m fading channel based on maximum ratio combining,is derived.The simulation results show that the detection probability decreases as the increasing of axis off angle,and the diversity combining can significantly improve the detection performance over fading channel.