摘要
LEO卫星移动通信系统中,卫星与终端的运动会造成可观的多普勒效应。当系统采用OFDM传输体制时,多普勒效应会造成OFDM数据点的旋转及子载波间干扰(ICI)。通过分析LEO卫星的运动规律,得到由卫星造成的多普勒频偏的规律性,该特性保证了多普勒频偏可被估算并消除;接着通过地面终端的移动规律,计算得到系统的多普勒频展;最后计算得到铱星系统和全球星系统的多普勒频展,在最优系统容量的准则下,得到在该系统中适用的OFDM子载波间隔。
In LEO satellite mobile communication systems,the movement of satellites and terminals leads to considerable Doppler Effect. When using Orthogonal Frequency Division Multiplexing（OFDM） technology in such system,Doppler Effect may cause rotation of OFDM signal and Inter-Carrier Interference（ICI）. In this paper,the characteristic of LEO satellite motion is analysed,and an esti- mating method is given. After this,Doppler spread caused by the movement of terminals is also deduced. Finally,referring to parameters of Iridium satellite system and Globalstar satellite system,the concrete values of Doppler shift and Doppler spread are calculated, and the optimal setting of sub-carrier bandwidth is given.
出处
《无线电通信技术》
2013年第2期4-6,42,共4页
Radio Communications Technology
基金
国家自然科学基金面上资助项目(61071083)
