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 HardwareDUL – Digital

Unit LTERU – Radio

Unit

SIMO

Tx/Rx1

Rx2

Cabinet DiagramFans

Radio

C Transmission

CC Power

RUs

DUL

SIU

Cabinet – No Jumpers

Power

DULs

RUs

SIU

Cabinet – Jumpers

Power

DULRUs

Antenna Jumpers

Diplexer Site

Diplexer

Input

Output

LTE

CDMA

Diplexer Detail

InputOutput

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

Cabinet Key

Sitemaster

Laptop with UE

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

Correct

Bent

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

Sector 4

• Verify all cables match colors in plumbing diagrams

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

Jumpers from cabinet

Antenna feeders

• Trace the antenna jumpers from the cabinet to the antenna feeders

Antenna Jumper Check – Diplex• Trace the antenna jumpers from the cabinet to the diplexer

Jumpers enter

Diplexer

Jumpers from cabinet

Antenna Jumper Check – Diplex• Trace the antenna jumpers from the cabinet to

the diplexer

Jumpers enter

Diplexer

Jumpers from cabinet

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

Adapters

Use high power attenuators

Ensure attenuators are connected to both Tx/Rx2 and Rx2

Attenuators

• Connect the attenuators to the RUL

Dummy Load Test

Attenuators

Dummy antennas

• Connect the dummy antennas to the attenuators

Dummy Load test• Power on the RUL

Power light on

Power Connector

Power Button

Dummy Load Test• Have EUTRAN unlock the target sector and lock

all other sectors

Ensure blinking

Dummy Load Test

Dummy antennas

• Place the UE near the 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 AzimuthTroubleshooting Steps

– Drive Test– Visual inspection of antenna direction

THANK YOU