Viavi CellAdvisor 5G, User Manual

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Using RFoCPRI Analyzer
Introduction
Cell sites today have a distributed architecture of the radio that consists of the radio equipment control (REC) or base band unit
(BBU) installed at the bottom of the tower and the radio equipment (RE) or remote radio head (RRH) installed at the top of the
tower. These two elements communicate with each other via the Common Public Radio Interference (CPRI) protocol over fiber links.
This distributed architecture provides the benefit of replacing coax-based feeders with fiber- based feeders, significantly reducing
the problems of signal loss and reflections. However, since all the RF interfaces reside on the RRH, any RF maintenance or
troubleshooting requires climbing to the top of the tower to access the RRH, increasing operational cost and unnecessary safety
issues.
CellAdvisor 5G provides the option of RFoCPRI that allows you to perform RF maintenance and troubleshooting activities on the
ground via the fiber interfaces at the BBU, significantly reducing maintenance time and operational expenses. Thanks to the
RFoCPRI technology, you can verify the CPRI control signals and extracts the IQ data transmitted between the BBU and RRH to
monitor and analyze the uplink interferences and the downlink signals.
You can also monitor current and history CPRI alarm status for LOS and LOF displayed on the interference measurement screen.
The RFoCPRI testing provides following measurements:
■
Spectrum Analysis
▪
Spectrum
▪
Spectrogram
▪
Spectrum Replayer
Selecting mode and measure
To start measurement, do the following steps:
1 Tap RFoCPRI on the MODE panel.
2 Tap any measurement mode from the following choices:
Spectrum Analysis > Spectrum, Spectrogram or Spectrum Replayer
NOTE:
You can choose RF Source On or Off in Setup menu after tap to CAA RF Power On if you have RF Source
option in your CAA(Cable and Antenna Analyzer).
Connecting cables
You can connect cables with a tap or without a tap as illustrated below. If you have connected cables directly from RRH and BBU
without using the nTap, you must turn on the through mode (Thru) in the CPRI parameter settings.
A SFP/SFP+ transceiver that is connected to your CellAdvisor 5G must be compatible with your DUT and you must have your
module information such as line rate, wavelength, and mode (MM or SM) handy.
Connection diagram for interference analysis
Without nTap (both Thru On/Off) With nTap (Thru On only)