BTS Field Maintenance Support

BTS Field Maintenance Support TOP10 Alarms and troubleshooting

Huawei Technologies Co., Ltd

Table des matières 1. Troubleshooting procedure:........................................................................................................ 4 1.2 - Preparation: ........................................................................................................................ 4 1.2 – Common BTS troubleshooting procedure: ......................................................................... 4 2- Alarms and troubleshooting procedure: ..................................................................................... 6 2-1- BTS startup faults: .............................................................................................................. 6 2.2- Power supply and environment monitoring faults: ............................................................. 8 2.2.1- Mains phase loss: .......................................................................................................... 8 2.2.2- PSU AC/DC Fault: ........................................................................................................... 9 4-

Abis interface fault: .............................................................................................................. 11 4.1- Abis transmission link fault: ............................................................................................... 11

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RF system fault:..................................................................................................................... 13 5.1- Call drop caused by high VSWR:......................................................................................... 13 5.2- Difficult access and high call-drop rate .............................................................................. 13

TOP10 Alarms ................................................................................................................................ 15

Huawei | BTS Field Maintenance and Support

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Region/Site ID:

All BSC

Date:

2010-03-22

Product:

BSC6000, BTS3900

INWI Contactor

N/A

Huawei Contactor

Elourouba Soufiane

Mobile Phone

N/A

Mobile number:

0646144277

E-Mail:

N/A

E-Mail:

[email protected]


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1. Troubleshooting procedure: 1.2 - Preparation: Before troubleshooting the BTS ensure that:  The BTS power supply is normal. If BTS power failure occurs, contact the power supply department to recover the power supply.  The connection between BTS and BSC LMT is normal.

1.2 – Common BTS troubleshooting procedure:

Figure 1 The following details the actions marked in figure 1: 1- Query current alarms: On the BSC LMT Choose Alarm Maintenance > Browse Alarm The Browse Alarm window is displayed:


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2- Clear the current alarms: Check the alarm description in the alarm details. An alarm description includes alarm name, alarm severity, the cause, alarm location, and suggestions for clearing the alarm. You can clear the alarms according to the alarm description, or refer to the suggestions in this chapter to handle some specific faults.


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3- Judge the type of the fault according to the faults : Faults type BTS start UP faults Power supply and environment monitoring faults Abis interface fault

RF system faults

Symptom

- The boards cannot be started. - The BTS reset itself frequently. - Power supply module is faulty. - Mains phase is lost. - Environment alarms is generated. - E1/T1 alarm is generated. - The OML, signaling or traffic link is faulty. - The signaling or traffic link is overloaded. - Alarms related to the RF system are generated. - The forward power is too low. - The call drop rate is high.

2- Alarms and troubleshooting procedure: 2-1- BTS startup faults: The symptom of BTS startup faults include:   

The BTS cannot start. The board cannot be started. The BTS reset itself frequently.


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Figure 2 Huawei | BTS Field Maintenance and Support

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The following details the actions marked on figure 2-1: 1- Check the hardware of the board. Make sure that the hardware of the board is normal. Check whether any alarm is generated. If so, replace the board according to the alarms or the indicators. 2- Check the voltage of the power supply. Make sure that the voltage of the power supply is normal. 3- Check the temperature of the BTS. Make sure that the temperature of the BTS is normal. 4- Check the software version. Make sure that the software version of the BTS is correct.

2.2- Power supply and environment monitoring faults: When the power supply and environment monitoring faults occurs to the BTS, solve them in the first place. This section describes the symptoms of some common power supply and environment monitoring faults, and troubleshooting procedures.

2.2.1- Mains phase loss: Symptom The BTS3900 report the “Power Supply Alarm”¸ The troubleshooting procedure for the main phase loss


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Figure -3The following details the actions marked in figure 3: 1- Check the power switches AC/DC power subrack power switches must be turned on. 2- Check the power supply of the site. Contact the power supplier or use a multimeter to confirm the power supply of the site. 3- Check connections of AC power cables and correct errors of any.

2.2.2- PSU AC/DC Fault:


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Symptom: The BTS3900 report “PSU failure Alarm” .The troubleshooting procedure of PSU fault :

Figure -4-

The following details the action marked in figure : 1- Check the data configuration for errors. 2- Check the power supply of the site. Huawei | BTS Field Maintenance and Support

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Contact the power supply department and check whether the power supply of the site is cut off. Alternatively, use a multimeter to measure the voltage between modules 3- Check the connections of AC power cables and correct errors if any.

4- Abis interface fault: This section introduces the symptoms of several common Abis interface faults and their troubleshooting procedures. Before handling the Abis interface faults, clear the power supply and environment monitoring faults first. 4.1- Abis transmission link fault:

Symptom The BTS report “E1/T1 alarm” like “E1/T1 local alarm or E1/T1 prompt alarm” Troubleshooting Troubleshooting procedure for the Abis transmission link fault.


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Figure -4The following details the actions marked in figure 4 1- Clear the fault of the power supply or transmission system. If disconnection of the transmission link is caused by the transmission or power supply system faults, contact the power supply personnel or transmission maintenance personnel to solve the problem as soon as possible. 2- Check the E1/T1 status. 3- Stop the test. 4- Loopback the transmission link section by section to locate the faulty part. Locate the faulty part of the transmission link and then clear the fault. The following problems may result in bad transmission link: - The board involved with the transmission link is faulty. Huawei | BTS Field Maintenance and Support

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The connector is in poor connection. The cable is damaged.

5- RF system fault: This section describes the symptoms of common RF system faults and troubleshooting procedures. Caution: Before handling the RF cable or replacing the RF parts, power off the corresponding RF module first.

5.1- Call drop caused by high VSWR: Symptom: The network signal received by handsets is rather weak. It is easy to cause call-drops. The BTS coverage area shrinks. Troubleshooting: If the VSWR of the antenna system exceeds the carrier Module VSWR warning alarm threshold, the VSWR warning alarm is generated. To Clean this alarm: Using the site master, check first the connector of the cable connecting to the antenna port of the carrier Module. Then Check whether the jumper connector on the tower or the jumper connector under the tower is securely connected to the feeder. When the fault is localized replace the fault part.

5.2- Difficult access and high call-drop rate Symptom: The network signal is strong, but the subscriber access success rate is low and the call-drop rate is high. Troubleshooting: The troubleshooting procedure for the problem of difficult access and high call-drop rate.


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Figure -6-

The following details the action marked in figure 6 1- Test the received signal strength indicator (RSSI) For RSSI test method, test whether the RSSI is normal according to the following standard: -

When there is no on-ongoing call, that is, the load is zero, the normal average RSSI ranges from -105dbm to 110dbm. 2- Check and clear the interference. When checking for interference, note the following points: -

Check whether the antenna installation position (such as antenna azimuth, antenna isolation) meets the requirements. If the main and the diversity RSSI values differ a lot, self excitation occurs to the antenna system with the larger RSSI. Check if the filters are installed in the CDMA and GSM sectors.


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3- Check the antenna system and cable connections of RF equipment and clear faults if any. When checking the antenna system and cable connections of RF equipment note the following points:  

Check that all connectors are in good contact. If the main and diversity RSSI values differ a lot, check the cable connections of the antenna system with the smaller RSSI for errors.

TOP10 Alarms 1- LAPD OML Fault : Description: The data link layer protocol between the BSC and the BTS is the LAPD protocol. To enable the communication between the data layers of the BSC and the BTS through the LAPD protocol, the LAPD Link should be established. The link carries operation and maintenance information is called OML, or LAPD OML. This alarm is generated when the BSC detects the LAPD OML disconnection between the BSC and the BTS or the BSC detects that the handshake with the BTS times out.

Impact on the system: -

All the BTS services are disrupted when the LAPD OML is disconnected. Fifteen minutes after the LAPD OML is disconnected, the corresponding BTS will be reset automatically.

System action: The BSC sends handshake messages to the BTS periodically, trying to reestablish the disconnection.

Possible causes:


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The transmission device or transmission link between the BSC and the BTS is faulty. The Abis interfaced board of the BSC is faulty. The BTS experiences power failure. The GTMU board or E1 lightning protection board of the BTS is faulty.

Handling procedure:


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Figure The following details the action marked in figure: 1- Check the trunk parent alarm: Log in to the LMT and then choose Alarm Maintenance>Browse Alarm. Check whether the BSC reports any parent’s alarms, then Rectify the fault according to the alarm help. Huawei | BTS Field Maintenance and Support

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2- Check the Abis interface board of the BSC : Check whether the Abis interface board of the BSC is in normal state ( please refer to section - -). 3- Check the BTS power supply: Contact the maintenance engineer on the BTS side and check whether the BTS is equipped with batteries. Then check whether the BTS experiences power failure on the BTS side. For more details please refer to section - 4- Check the GTMU board: Reinsert the GTMU board, then check whether the alarm is cleared, if the alarm is not cleared replace the GTMU board. Caution: If the site is cascaded, you need to change DIP switch configuration.

2- Sensor failure: Description: This alarm is reported when an analog sensor fails to work properly.

Impact on the system: The BTS cannot work properly, and heat dissipation of the system is affected.

System action: None.

Possible causes: - The sensor is not installed. -

The cable connected to the sensors is faulty. The sensor is faulty. The monitoring unit is faulty.

Handling procedure: Huawei | BTS Field Maintenance and Support

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Figure The following details the action marked in figure : 1- Check the sensor : Check whether the sensor is installed. 2- Check the cable connections of the sensor: Huawei | BTS Field Maintenance and Support

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Check whether the cable of the sensor is properly connected. 3- Replace the sensor: Replace the monitoring unit or the external sensor. Caution: For batteries sensors, for the cable connections, be sure that the green and whitegreen cables are connected in the right way: green with green cable and white with the white one (see picture below).

3- Temperature sensor fault : Description: This alarm is reported when the built-in temperature sensor of the DHEU or the external temperature sensor of the DHEU is abnormal.

Impact on system: Huawei | BTS Field Maintenance and Support

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The heat dissipation of the system is affected.

System actions: None Possible causes: -

No temperature sensor is installed. The cable that connects to the temperature sensor is faulty. The temperature sensor is abnormal. The heat exchanger is faulty.

Handling procedure:


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Figure The following details the action marked in figure 1- Check the temperature sensor: Check whether the temperature sensor is installed. Huawei | BTS Field Maintenance and Support

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2- Check the cabling of the temperature: Check whether the cabling of the temperature is proper. 3- Replace the external temperature sensor that connected to the DHEU.

Caution: For the temperature cable alarm (on the left of the picture), the white cable of the alarm cable should be connected to the orange one, and the orange of the alarm cable to the white one.

4- Board type mismatch alarm: Description: Huawei | BTS Field Maintenance and Support

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The alarm is reported when the type of a board actually installed in a slot of the rack is different from that of the board configured in the same slot at the BSC side.

Impact on system: The RFU in the slot where alarm is generated cannot work.

Possible Causes: The board type actually installed in the slot of the rack is different from the data configured in slot at the BSC side.

Handling procedure: Replace the board according to the system configuration.

5- SFP port inconsistency alarm : Description: The SFP port configuration on the RFU of the BSC is inconsistent with the physical connection.

Impact on system: The communication between BBU and RFU fails when the alarm occurs.


Possible causes: - Topology configuration on the SFP port is inconsistent with physical connection. - RFU chain on the SFP port is disconnected. - A CPRI port on the RFU chain on the SFP port is blocked Handling procedure: Huawei | BTS Field Maintenance and Support

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Figure The following details action marked in figure 1- Check the RFU configuration at the SFP port : Based on the detailed alarm information, check the RFU configuration at the SFP port on the LMT.


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2- On site check the actual RFU connections and configuration : Based on the detailed alarm information, check whether the CPRI LED on the main controlling board (GTMU) and the CPRI LED on the RFU are steady ON in red. Then rectify the CPRI link fault.

6- PMU communication alarm: Description: This alarm is triggered when the communication between the GTMU and the PMU is interrepted.

Impact on the system: The BTS cannot monitor the PMU and the PSU upon the occurrence of this alarm.


Possible causes: -

The DIP switches of the PMU are incorrect. The communication cable of the PMU is incorrectly connected. The MON1 port of the UPEU boards is faulty. The software of the main control boards is faulty.

Handling procedure:


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Figure The following details the action marked in figure 1- Check if the cables are correctly connected: Check whether the DIP of the PMU is correct. Check the port on the APMI to which the BBU is connected. Ensure that all the cables are correctly connected. Check the Huawei | BTS Field Maintenance and Support

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MON1 port to wich the BBU is connected. Ensure that the cable is not connected to the MON0 port. Check the RJ45 port on the panel of the PMU. The RJ45 port should be connected to the RS232 port. 2- Check whether the heat exchanger board communication alarm is generated on the BSC side: The alarm is generated. Replace the UPEU board (the MON port is faulty). If the alarm is not cleared, the main control board might be faulty. Clear the alarm according to the troubleshooting procedure of the main control board.


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BTS Field Maintenance Support

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