Ericsson MINI-LINK TN R3 ETSI Technical Description page 74

MINI-LINK TN R3 ETSI
The block holds a Device Processor (DP) running plug-in unit specific software.
It handles BER collection and communicates with processors in the RAU
through the RCC.
Exchange of control and supervision data over the hop is made through the
HCC.
4.2.2.8 SPI
This block interfaces the SPI bus and handles equipment status. Failure is
indicated by LED's on the front of the unit.
4.2.2.9 Power
This block interfaces the Power bus and provides secondary voltages for the
unit. All plug-in units have a standard power module providing electronic soft
start and short circuit protection, filter function, low voltage protection, DC/DC
converter and a pre-charge function.
Furthermore, this block provides a stable voltage for the RAU, distributed in
the radio cable.
4.2.2.10 Cross Polarization Interference Canceller
MMU2 F 155 is equipped with Cross Polarization Interference Canceller (XPIC)
functionality.
Microwave signals can be transmitted in two separate and independent
(orthogonal) polarizations, vertical and horizontal. The signals can be
transmitted at the same time using one dual polarized antenna. The wanted
polarization is called co-polarization and the unwanted/interference polarization
is called cross-polarization.
Even though the polarizations are orthogonal there is a small interference
between them, in the antennas and due to propagation effects over the
hop. The effect of this interference needs to be cancelled out with the XPIC
functionality
In XPIC, each polarization path receives both the polar signal and the
cross-polar signal. The receiver subtracts the cross-polar signal from the polar
signal and cancels the cross-polar interference. XPIC processes and combines
the signals from the two receiving paths to recover the original, independent
signals.
An XPIC solution doubles the wireless link capacity and enables operators to
reduce cost in terms of their frequency license fee.
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