Chapter 16
Performing RFoCPRI Testing
JD700B Series User’s Guide
547
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.
JD700B series analyzers provide 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.
The RFoCPRI testing provides following measurements and analysis:
◼
Layer 2 monitoring of link maintenance alarms and optical power
o
Loss of Signal (LOS) – Code violation or low optical power
o
Loss of Frame (LOF) – Frame synchronization or alignment
o
Remote Alarm Indication (RAI) – Any error including LOS and LOF
o
SAP Defect Indication (SDI) – Link not to be used for service access points
o
Optical Rx and Tx power levels
◼
Layer 2 terminate testing or Layer 2 BERT
◼
Interference analysis
o
Spectrum
o
Spectrogram
o
Received Signal Strength Indicator (RSSI)
o
Spectrum replayer
o
Dual Spectrum
o
Dual Spectrogram
o
Quad Spectrum
◼
PIM detection of single or multiple carrier(s)
◼
LTE-FDD downlink signal analysis over CPRI
o
Spectrum
o
RF analysis – Channel Power and Occupied Bandwidth
o
Power vs. Time (Frame)
o
Modulation analysis – Constellation, Data Channel, Control Channel, Subframe, Frame,
Time Alignment Error, and Data Allocation Map
o
Power Statistics CCDF
◼
LTE-TDD downlink signal analysis over CPRI
o
Spectrum
o
RF analysis – Channel Power and Occupied Bandwidth
o
Power vs. Time (Frame)
