On Polarization Diversity in Mobile Communications
- Xing-Peng Mao, Jon W. Mark
- Communication Technology,
WCDMA signal is enhanced using 3D polarization diversity where the receiving antenna consists of three orthogonal dipoles to achieve the vertical, horizontal and orthogonal one to both of them. After random reflections, the polarization state of the signal will be independent of the transmitted polarization. The non line-of-sight path would change the polarization at the receiver which can affect the quality and the strength of the received signal. This method is proposed for WCDMA mobile systems which are commonly used in the third generation (3G). The receiver RAKE is used to identify the multipaths of receiving elements for each polarization state. The received signals of the antenna elements are combined with coherent detection on the maximum ratio combining (MRC) for signal maximization. Coherent detection necessitates estimation of the amplitude and phase of the propagation channel. It is shown that the average SNR is only degraded by errors in estimating the phase, but not the amplitude. This method can be applied even in the near field.