Site Troubleshooting Guide
LTE
RBS 6000 Series
RBS 6102
RBS 6101
RBS 6201
RBS 6601
RBS 6301
RRU
• MetroPCS primarily uses RBS 6201 inside a weatherized cabinet
• MetroPCS primarily uses SIMO
• Some sites will use RBS 6601 with RRUs, but not currently available
Weatherized Cabinet
• Majority of
MetroPCS sites are
outdoors
Cabinet – Back
RBS 6201 Hardware
DUL – Digital
Unit LTE
RU – Radio
Unit
SIMO
Tx/Rx1
Rx2
Cabinet Diagram
Fans
Radio
RUs
DUL
CC
Power
SIU
C
Transmission
Cabinet – No Jumpers
Power
RUs
DULs
SIU
Cabinet – Jumpers
Antenna
Jumpers
Power
DUL
RUs
Diplexer Site
Diplexer
LTE
CDMA
Output
Input
Diplexer Detail
Input
Output
Diplexers
Visit Preparation
• Printed Materials
– RFDS Sheet with all plumbing diagrams
– Notes about site access
– Directions
– Satellite image
– Site Shakedown report
• Equipment
– Cabinet key
– Dummy load set
– Sitemaster
– Laptop setup to run TEMS Investigation with UE
Equipment
Sitemaster
Laptop with UE
Cabinet Key
First Steps
• Best Practices
– Take photos!
– Be prepared
– Ensure E-UTRAN support is available
– Notify relevant parties based on customer procedures
• Visual Inspection
– Make sure nothing immediately looks incorrect
– Trace the RU-DUL cables to ensure there are no swaps
– Ensure the RU-DUL cables have a good connection
– Check small QMA wave guide for damage and ensure connection
Photos
• Take a photo of the site label to identify pictures
RU to DUL Jumper check
• Ensure the RU-DUL jumpers are correct
DUL
RU-DUL
Jumpers
RU
RUL QMA Wave Guide Check
• Check small QMA wave guide for damage and
ensure connection
Bent
Correct
RUL QMA Wave Guide Check
Bent Connector
Disconnected Connector
Common Issues
•
•
•
•
Sector Swaps
DL or UL throughput low
Bad or no coverage
Azimuth incorrect
Sector Swaps
• Causes
– RU-DUL cables
– Jumpers from cabinet to diplexer
– Jumpers from diplexer to antenna feeders
– Antenna feeders to antennas
– CDMA incorrect
– Do not trust colors on cables
• Troubleshooting Steps
– E-UTRAN lock test
– Cable tracing
E-UTRAN Lock Test
• Procedure
– Have E-UTRAN lock a single sector
– Verify the reference signal transmit light stops
blinking
– Repeat for each sector
• Conclusion
– Ensures that the DUL is configured correctly
– Verifies there is no RU-DUL cable swap
E-UTRAN Lock Test
• Blinking
– Transmitting
reference
signals
• No Light
– Locked
Antenna Jumper check
• Verify all cables match colors in plumbing diagrams
• Non-diplex site
– Trace the antenna jumpers from the RUL to the back of the
cabinet
– Trace the antenna jumpers from the cabinet to the antenna
feeders
• Diplex site
– Trace the antenna jumpers from the RUL to the back of the
cabinet
– Trace the antenna jumpers from the cabinet to the diplexer
– Trace the antenna jumpers from the diplexer to the antenna
feeders
Antenna Jumper Check
• Verify all cables match colors in plumbing diagrams
Sector 4
Sector 5
Sector 6
Antenna Jumper Check
• Trace the antenna jumpers from the RUL to the
back of the cabinet
Jumpers exit cabinet
Jumpers at RUL
View – Cabinet Back
Jumpers exit cabinet
Antenna Jumper Check
• Trace the antenna jumpers from the cabinet to the antenna
feeders
Jumpers from cabinet
Antenna feeders
Antenna Jumper Check – Diplex
• Trace the antenna jumpers from the cabinet to the diplexer
Jumpers from
cabinet
Jumpers
enter
Diplexer
Antenna Jumper Check – Diplex
• Trace the antenna jumpers from the cabinet to
the diplexer
Jumpers from
cabinet
Jumpers
enter
Diplexer
DL or UL throughput low
• Causes
– Backhaul
– Antenna system and jumpers
– Hardware problems with RU-DUL
• Troubleshooting Steps
– Dummy Load Test
– Feeder Sweeps
– E-UTRAN support
Dummy Load test
• Procedure
– Trace the power connector to the RUL and turn it off
– Detach the antenna jumpers from the RUL
– Connect the attenuators to the RUL
– Connect the dummy antennas to the attenuators
– Power on the RUL
– Have EUTRAN unlock the target sector and lock all other sectors
– Place the UE near the dummy antennas
– Upload and download a file and record a TEMS log
• Conclusion
– Eliminates or identifies antenna system cause of problem
Dummy Load Test
• Trace the power connector to the RUL and turn
it off
Power light off
Dummy Load Test
• Detach the antenna jumpers from the RUL
Disconnected
Jumpers
Dummy Load Test
• Connect the attenuators to the RUL
Use high power
attenuators
Adapters
Attenuators
Ensure attenuators are connected
to both Tx/Rx2 and Rx2
Dummy Load Test
• Connect the dummy antennas to the
attenuators
Attenuators
Dummy
antennas
Dummy Load test
• Power on the RUL
Power light on
Power Button
Power
Connector
Dummy Load Test
• Have EUTRAN unlock the target sector and lock
all other sectors
Ensure blinking
Dummy Load Test
• Place the UE near the dummy antennas
Dummy
antennas
UE
Dummy Load Test
• Upload and download a file and record a TEMS
log
Feeder Sweeps
• Tests
– Voltage Standing Wave Ratio
– Return Loss
– Distance to Fault
– Covered in a different guide
• Conclusion
– Determines if there are problems in the antenna system
E-UTRAN support
• Procedure
– Connect to the cell (dummy load or otherwise)
– Download or upload a file
– Have E-UTRAN monitor the node
• Conclusion
– Determines if there is a configuration problem or a
problem in the backhaul
Bad or No Coverage
• Causes
– Antenna System
– Jumpers not connected
– Hardware problems with RU-DUL (damaged
connectors)
• Troubleshooting Steps
– Ensure all connectors are tightly secured
– Dummy Load Test
– Feeder Sweeps
Incorrect Azimuth
Troubleshooting Steps
– Drive Test
– Visual inspection of antenna direction
THANK YOU