多时间尺度短波信道建模与仿真方法

Modeling and simulation of multiple time scales HF channel

为解决Watterson模型不能准确反映较长时间内短波信道变化情况的问题,通过引入IONCAP电离层传播预测模型和对数正态过程时间序列,给出一种适合于多种时间尺度的短波信道建模和仿真方法。通过ITS预测软件得到小时级的SNR变化规律;借助平均周期图法从实测数据中提取信道特征参数,并代入Alpha滤波器获得反映分钟级信道变化的SNR时间序列;将获得的SNR值进行叠加,输入Watterson模型得到新的多时间尺度模型。仿真结果表明,采用Alpha滤波器能够准确反映短波信道在分钟级上的变化规律,建立的多时间尺度信道模型比Watterson模型能更好地反映较长时间上的信道变化情况。

To solve the problem that Watterson model is invalidated to reflect HF channel features at long time scale, a multiple time scales HF channel modeling and simulation method is proposed by introducing IONCAP ionospheric propagation prediction model and the lognormal random process time series. Firstly, hourly changes of channel SNR is predicted by ITS propagation software. Then the channel characteristic parameters are acquired from the average periodogram of the measured data, which are imported into the alpha filter to obtain the minutely SNR time series. The novel multiple time scales HF channel model is estab lished by adding the SNR values and building Watterson model lastly. Simulation results show that the alpha filter can depict precise minutely changes of HF channel, and the proposed model can match the channel variations of various time scales much better than Watterson model.