摘要
在认知无线电的空闲频段二次利用中,针对感知用户通信可能引起的多普勒效应对临近信道带来的干扰的问题,提出了一种基于多普勒频谱扩展程度量化的实时计算方法。首先利用平方根升余弦函数使训练码频谱限定为特定带宽,并将感知空闲频谱划分为基带频段和保护频段,其次将保护频段划分为多个保护频段子区间,分别计算各个保护频段子区间的信号功率,最后累加信号功率不为零的保护频段子区间,即为整个信号的频谱扩展程度。文中方法同时也满足了对空闲频段实时检测的要求。仿真验证了在不同移动速度条件下,基于保护频段子区间的信号谱估计来计算多普勒频谱扩展的程度。
For the secondary utilization of the idle spectrum in cognitive radio,a real-time calculation method based on the quantization of the Doppler spectrum expansion degree is proposed aiming at the interference of the second user communication on the adjacent channel,which is caused by the Doppler effects.Firstly,the square root raised cosine function is used to limit the training codes spectrum to a certain bandwidth,and each sensed idle spectrum is divided into base band and guard band.Secondly,the guard band is divided into multiple subintervals,and the signals power of each subinterval is calculated separately.Finally,it accumulates the guard band subintervals of the signals power not zero.The whole spectrum expansion of the signal is the accumulated value,and the method simultaneously meets the requirements of real-time detection of the idle spectrum.The simulation testifies that the range of Doppler spectral spread is calculated based on the signal spectrum estimation of the subintervals of the guard band under the conditions of different moving speed between the transmitter and receiver.
出处
《信息技术》
2017年第12期168-171,共4页
Information Technology
