基于软件无线电USRP的多径衰落实验

Multipath Fading Validation Experiment Based on SDR USRP

  • 摘要: 无线信号的多径衰落很难直观观测且不易验证。针对这些问题,本文利用软件仿真(Simulink)+硬件系统(SDR-USRP设备)搭建真实的无线传输系统,采用了多传输线模拟、室内无遮挡电波传播、有遮挡电波传播三种多径信道方式,验证多径传播是否一定会导致信号衰落。以USRP获取的无线电波信号采样数据,用局部最大值法提取信号包络、用统计拟合方法刻画信号的衰落特性,验证了多径传播不一定会导致信号的衰落这一结论,同时也验证了非视距多径传播的接收信号其包络服从瑞利分布,实现了“看得见”的多径衰落!

     

    Abstract: The multipath fading of radio signals is hard to verify and intuitively observe. In this paper, a combined wireless communication system by software simulation platform (Simulink) and hardware devices (SDR-USRP) is established, by adapting 3 multipath propagating modes: multi-cable transmission, line-of-sight radio propagation, non-line-of-sight radio propagation, to test the question “does multipath propagating inevitably result in signal fading?”. The envelope of the captured physical signal is then derived by using Local Maximum Method, and further the envelope samples are used for fading channel modeling by statistical data fitting method. A conclusion “multipath propagating does not always cause signal fading” can also be draw by this experiment. Meanwhile, the envelope of received mixed signal after transmitting over the nun-line-of-sight multipath channel following the Rayleigh distribution is then tested, hence a “visible” multipath fading channel is implemented.

     

/

返回文章
返回