Cross Polarization Interference Cancellation (XPIC) is used in directional radio to increase frequency spectrum effectiveness and to compensate for interference between microwaves. To increase transmission capacity, directional radio uses a frequency that is orthogonally polarized: vertically and horizontally. This mode of operation is called Co-Channel Dual Polarized (CCDP). Due to refractions, diffractions and reflections
, both polarization planes interfere with each other during transmission. This interference must be compensated for on the receiving side. By reducing the interference between vertically and horizontally polarized frequencies, interference is reduced
andthe transmission bandwidth
isincreased at the same time. The problem of interference occurs mainly in large cities and in mountainous areas, where radio waves reflect off skyscrapers and mountains.
Technically, XPIC processes the received and polarized frequencies with the other signal attenuated.
For example, the received vertically polarized signal, which contains interference from the horizontally polarized signal, is combined with a portion of the received horizontally polarized signal, compensating for the interference in the vertically polarized signal. The interference is reduced and the transmission bandwidth improves.