What is XPIC,
why is it used,
how is it used,
and why is it used with the CCDP and not with the ACAP:
First, before explaining what the XPIC is and why it is used, we must know the difference between single polarized and dual polarized transmission
For single polarized, the signal is transmitted on one polarization and one frequency, either vertical or horizontal
While the dual polarized, the signal is sent both vertically and horizontally at the same time and on the same frequency
We do this to increase transmission capacity.
There are two types of Dual polarized transmission and they are ACAP and CCDP:
ACAP: Adjacent Channel Alternate Polarized
In ACAP, a channel of signal is sent to V or H, meaning that a signal is sent to V, and then another signal is sent to H
CCDP: Co-Channel Dual Polarized
In CCDP, two signal are sent to V and H at the same time and no interference occurs between them because the V and H are orthogonal, so the receiver can recover the signal without problems.
But in fact, there is a Cross Polarization Interference because of the channel (Channel deterioration) problems.
In this case, the XPIC at RX technology must be used in order to retrieve the original signal.
What is the feature of XPIC
In the transmitter, two signals are sent, one on the V and the other on the H at the same time and on the same frequency
Cross Polarization Interference occurs on the receiver due to problems with the Channel and Antenna XPD
Using XPIC technology as follows to retrieve the Original Signal:
Each receiver in V and H converts the RF Signal to IF Signal and separates them on Two Channels
The first channel is sent to its modem, RTN / TN / IPASO
And the second channel is sent to its modem on the RTN / TN / IPASO
In addition to a copy of the Channel that is sent to the other modem under the name XPIC Signal
Each Modem collects the IF Signal and XPIC Signal in order to overcome the Cross polarization Interference and restore the Original Signal.
Conclusion:
The XPIC is used with the CCDP because two signals are sent over Vertical and Horizontal waves. Because of the channel deterioration and antenna XPD, interference occurs between the two channels. To overcome this, the XPIC is used as follows:
At the Receiver, both the Receiver and the Vertical unit and Horizontal Unit transfer the two RF signals into IF signals and then send them to each of the Modems who reach them through the IF cables, in addition to a copy of these Signals, which each of them sends to the other modem, which in turn does the compilation of this Signal, and then retrieves the .
Thanks.
