Troubleshooting Steps

1. After receiving the call from NOC, First confirm the alarms which came before OML fault alarm & if there is some power/Tx alarm, do the proceedings accordingly.

2. If NOC informed you that multiple sites are down around the same time, then try to find the common thing among them. Try to check the common route between them or any Hub site or any specific lease line/MW link involved.

3. After reaching on site, check all the Power breakers.4. Check the IDU & its working condition physically.5. Check BTS & check all the LED’s physically specially LIU0 on

GTMU.6. Give the Internal loop from DDF Krone towards the BTS & check

whether the status of LIU0 is normal or not, If it is normal then GTMU is most probably OK.

LIU0 will be off when E1 is normal.LIU0 will be on when E1 is break.LIU0 will be blinking if only Tx is up & Rx is down (check patching on DDF)

7. Check the patching status through LED & try to re punch the DDF Krone & check with NOC again.

8. Try to give the loop towards the BSC & if it is not ok then move to far end to check the loop from there & continue it till BSC, till you find the missing node.

9. During all this troubleshooting, stay in touch with Front office.

During all this, if you think there is a problem in GTMU then replace it & if the problem is resolved then again replace the new GTMU with old one to confirm that old GTMU is faulty.Try to give hard reset to the BTS in b/w this troubleshooting.

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 31

Board Port Connector Type Description

GTMU

CPRI0～CPRI5

SPF

Ports for the communication between the BBU and the RF

module; support input and output of the optical and

electrical signal.

ETH RJ45 Port for local maintenance and commissioning

FE0 RJ45

Connects the BBU to a routing device in the equipment

room through the Ethernet cable to transmit network

information.

FE1 DLC

Connects the BBU to a routing device in the equipment

room through the optical cable to transmit network

information.

USB USB Enables the automatic software upgrade from a USB disk.

TST USB Provides a reference clock for the tester.

E1/T1 DB26 female

Provides the input and output of the four E1/T1 signals

between the GTMU and the UELP or between the GTMU

and the BSC.

BBU Hardware – GTMU Board

Ports on the GTMU panel:

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 32

BBU Hardware – GTMU Board

LEDs on the GTMU:

LED Color Status Description

RUN Green

ON The board is faulty.

OFF No power supply is available or the board is faulty.

ON for 1s and OFF for 1s The board is operational.

ON for 2s and OFF for 2s The OML link is abnormal.

ON for 0.125s and OFF for 0.125s The board is loading software.

ALM RedON A fault occurs in the running board.

OFF No alarm is generated.

ACT GreenON The board is operational.

OFF The board is faulty.

LIU0~LIU3 Green

ON This link is not used.

ON for 0.125s and OFF for 0.125s A remote E1/T1 alarm is generated.

OFF This link is operational.

CPRI0~CPRI5

Green ON The CPRI link is normal.

Red ONThe reception of the optical module is abnormal and an

alarm is generated.

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 33

BBU Hardware – GTMU Board

DIP Switches:

DIP SwitchDIP Status

Description1 2

SW1

ON ON The E1 impedance is set to 75 ohms.

OFF ON The E1 impedance is set to 120 ohms.

ON OFF The T1 impedance is set to 100 ohms.

DIP SwitchDIP Status

Description1 2 3 4

SW2

ON ON ON ON

When four 75- ohm E1 links are faulty, all the

DIP bits of S2 should be set to ON

(unbalanced mode) so that the Faults are rectified.

OFF OFF OFF OFFAll the DIP bits of S2 are set to OFF (balanced

mode) by default in all modes.

HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential Page 34

BBU Hardware – GTMU Board

DIP Switches:

DIP SwitchDIP Status

Description1 2 3 4

SW5

ON ON ON ON The E1 link cannot be bypassed.

OFF ON ON OFF The E1 link of the Level 1 cascaded BTS can be bypassed.

ON OFF ON OFF The E1 link of the Level 2 cascaded BTS can be bypassed.

OFF OFF ON OFF The E1 link of the Level 3 cascaded BTS can be bypassed.

ON ON OFF OFF The E1 link of the Level 4 cascaded BTS can be bypassed.

OFF ON OFF OFF The E1 link of the Level 5 cascaded BTS can be bypassed.

DIP SwitchDIP Status

Description1 2 3 4

SW4

ON ON ON ON The E1 link can be bypassed.

OFF OFF OFF OFF The E1 link cannot be bypassed.