一种快速高效的无线信道实现方法

Efficient Channel Simulator for Mobile Radio Communications

提出了一种快速高效的基于IIR滤波器的无线信道实现方法。根据所需生成信道功率谱,IIR滤波器在频域用LMS(最小均方)算法进行优化设计,这种方法适用于任意的功率谱;通过线性内插和抽取,可实现任意带宽的时变无线信道。仿真表明在Clarke均匀散射Rayleigh信道假设下,新方法的二阶统计特性与传统无线信道生成方法如SOS(正弦波叠加)、FFT滤波以及AR滤波法等完全一致,但新方法的滤波器阶数可以做到很低,因此具有快速高效的优点。另外,提出的方法适合非均匀散射环境的信道设计,文章最后讨论了新方法在非均匀散射环境的仿真实现。

A new wireless channel simulator was proposed,using an IIR filter to filter independent white Gaussian variables. Firstly,the IIR filter was implemented based on the desired power spectral density （PSD）,employing the least mean square （LMS） algorithm in frequency domain. Then the arbitrary normalized maximal Doppler frequency,which is also known as the normalized digital bandwidth of the generated channel,was achieved by linear interpolation and decimation. Under the assumption of isotropic scattering Rayleigh fading channels,simulation shows the second order statistics of the proposed method is consistent with the traditional methods,such as the sum-of-sinusoids （SOS）,the FFT,and the AR,with lower order of the IIR filter. Consequently,the new simulator is both efficient and fast. Furthermore,the new method is also suitable for non-isotropic scattering environments which are more practical than the isotropic scattering assumption,and the application is also treated under those cases.