OFDM系统中时域和频域波束形成的比较

Comparison of Time Domain and Frequency Domain Beamforming in OFDM Systems

正交频分复用(OFDM,Orthogonal Frequency Division Multiplex)和智能天线的结合能够有效的提高频谱利用率和增大系统容量。在OFDM系统中,智能天线的算法有两种:时域(Pre-FFT)波束形成和频域(Post-FFT)波束形成算法。Post-FFT被普遍认为性能上优于Pre-FFT。研究了这两种算法,并基于Matlab仿真工具,给出了两种方法在不同天线阵元数、导频数、信道多径数下的误码率比较。仿真结果表明,时域波束形成和频域波束形成在不同情况下各能展现出优于对方的表现。

The combination of OFDM （orthogonal the frequency division the multiplex） and smart antennas can effectively improve the spectrum utilization and increase system capacity. In OFDM systems, time-domain （Pre-FFT） beamforming algorithm and frequency-domain （Post-FFT） beamforming algorithm are two smart antenna algorithms. Post-FFT is generally considered better than Pre-FFT. In the paper, both Pre-FFT and Post-FFT beamforming are studied. The BER performance of these two methods is simulated with the software Matlab under different numbers of antennas, pilots and channel multipaths. The experiment result shows that one algorithm could perform better than the Other in different conditions.