Ka波段雨衰减时间序列的合成及性能仿真

Generation of Rain Attenuation Time Series and Performance Simulations at Ka-Band

在Ka波段(30/20GHz)卫星通信系统传输中,降雨衰减是导致信号衰落的重要原因之一。为了通过功率控制算法来补偿动态雨衰减,用ITU-R降雨衰减预测模式,通过最小二乘曲线拟合方法详细推导我国北京地区雨衰减统计分布的参数,获得北京地区的动态雨衰减时间序列;用下行链路雨衰减预测上行链路雨衰减的方法,为上行链路功率控制算法奠定了基础;采用QPSK调制,分别考虑AWGN信道和莱斯多径衰落信道,将有小雨、中雨、大雨这三种降雨与没有降雨情况进行性能对比,仿真结果表明雨量越大对系统的影响越严重。

In satellite communication system transmission at Ka band （30/20GHz）, the rain attenuation is one of the most important reasons for signal fading. In this paper, in order to compensate for dynamic rain attenuation by the power control algorithm, based on the ITU recommendation rainfall attenuation prediction model, firstly, statistical distribution parameters of rainfall attenuation for Beijing areas in our country were derived in detail by a method of the least squares curve fitting. Secondly, dynamic rain attenuation values were produced by the parameters. Then, the uplink attenuation was estimated from the downlink attenuation for uplink power control. Finally, after QPSK modula- tion, signals were polluted by additive noise in AWGN channel and rice fading channel respectively ; simulations were performed based on the effect of light rain, middle rain, heavy rain and no rain on signals. The simulation results show that the greater the rainfall, the worse the effect on the systems.