Wideband Modeling of Land-Mobile-Satellite Channel in Built-Up Environment

This paper presents a propagation model for land-mobile-satellite (LMS) wideband radio channel in built-up environment. The model characterizes the behavior of the radio channel, under shadowing and multipath effects due to buildings, with variation of the elevation angle of the satellite. The wideband parameters (coherent bandwidth and time delay spreading) for LMS channel, in residential and urban environments, are computed. These parameters can be considered as a measure of the amount of ISI (inter-symbol interference) of the radio channel, which distorts the received signal and accordingly increases the bit error rate. The calculated values for these parameters using our model, show very good agreement with the corresponding measured ones, which accordingly shows the validity of the developed model for radio channel design in satellite mobile communication systems.

利用电磁波极化实现微蜂窝系统扩容的研究

为利用电磁波极化实现移动通信系统扩容 ,对MichaelR .Andrews等人的发现[1] 做了进一步研究。通过实验测试和计算机模拟 ,结果表明 ,原文所提供的扩容方法仅在一定范围内 (实验测试为 12 0m )有效 ,随着收发天线距离的增加 ,附加极化状态数将因散射波强度的减弱而减小 ,因此这种扩容方法只适用于微蜂窝小区。另外 ,还详细介绍了实验测试方案及结果 ,可作为进一步研究的参考。