Andrew Node C, User Manual

Page: 40 / 62

User’s Manual for Node M and Node C
Network Elements
Page 40 M0121A4A.doc
5.2.3. Digital ICE (Digital Interference Cancellation Equipment)
Digital ICE has been developed to enhance antenna isolation. This feature enables
the Node M/C to provide coverage in areas where effectivity is decreased due to
physical site limitations which cause insufficient antenna isolation.
Antenna isolation is the RF loss measured between the donor antenna and the
coverage antenna. If the gain of the network element exceeds the path loss,
feedback in form of oscillation occurs. The isolation is usually dominated by the direct
path loss from one antenna to the other, but reflections can contribute to or even
affect antenna isolation. Digital ICE cancels the signal from the primary feedback
path, thus allowing the gain of the network element to be increased.
The required delay resulting from the on-site conditions is measured by the DCM and
set accordingly.
For software setting commands please refer to the online help screens.
The Digital ICE function can be enabled or disabled in the “Technician Setup” page.
Isolation and gain margin* can be checked in the “Status and Reports” menu
accessible via the home page of the web interface (see software manual).
* gain margin = antenna isolation minus Node M/C gain
5.2.4. VSWR (Voltage Standing Wave Ratio)
This feature enables the provider to query the status of the antenna system (antenna
and cable). The voltage standing wave ratio of the DL output antenna port is
measured.
If the VSWR falls below the value set in the
Alarming Management of the software,
an alarm is released. The alarm can be forwarded to the OMC where the faults and
irregularities can be acknowledged and eliminated promptly.
The current VSWR value can be checked in the “Status and Reports” menu
accessible via the home page of the web interface.