# What does co-phasing of cross-polarized antennas mean?

I was working with the 3GPP release 14.6, and it mentioned that modern communication systems have cross polarized antennas, and in order to perform beam-forming we need to co-phase our pre-coder.

Pre-coding is an algorithm we use at the transmitter side in order to aid our performance at the receiver. We model our system as $y = Hx$ where H is the channel,x is transmitted data and y is received data.

Instead of sending $x$ we send $Wx$ where W is our pre-coder, our system would then be $y = HWx$ assuming we have the channel at the transmitter side we can just make $W = H^{-1}$ that way the channel doesn't affect the data.

What does co-phasing between cross-polarized antennas mean and how does it affect my precoder?

• Perhaps you could add more detail about the antennas and explain what a precoder does. But it sounds to me like a circularly-polarized array where the vertical and horizontal antennas are fed in quadrature (90° phase delay). – Mike Waters Sep 17 '18 at 15:26