cross polarization interference problem in polarization diversity

What is cross polarization interference? Why does this not take place if the channel doesn't vary too much? I read that cross polarization interference deteriorates polarization diversity technique. How?

Thanks in advance.:-D

Hello,

If you transmit a vert. pol. wave, you would receive on both a vert. pol and hor. pol. antenna, you would only receive on the vert. pol. antenna (assuming free space, no rain effects, etc).

However due to reflections waves with vert. pol. may change their polarization vector, so they get a hor. component, and vice versa. So practically spoken, in a real world with reflections, the hor. pol. receiving antenna will receive some signal from the transmitter with vert. pol. antenna. One can see this as interference when using both polarizations on the same frequency and in the same EM environment.

you may know that hor. and vert. polarization is used in sattelite communication to enable two communication channels on the same frequency.

Thank you. But how does this deteriorate the polarization diversity. This seems to improving polarization diversity.

In my opinion, you are right, it should improve polarization diversity. When there was no cross polarization, you had only two paths, now you have four.