Owb404400 Nodeb Wcdma v200r011 Troubleshooting Issue 1.00

8/13/2019 Owb404400 Nodeb Wcdma v200r011 Troubleshooting Issue 1.00

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Confidential Information of Huawei. No Spreading Without Permission

WCDMA NodeB Troubleshooting


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Please visit the technical support website for the contact information of the local branchoffices

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As defined by the protocol, the range of received total wide band power (RTWP) is -

1064 dBm.

Therefore, the RTWP is abnormal if its value is greater than -102 dBm or less than -110dBm continuously.

In addition, the RTWP is also abnormal if its value is greater than -80 dBm in rush hours.

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Check the uplink RF sensitivity

Run the following two MML commands: DSP RFDESPARAM and DSP DESENS. Then, view

the execution results. Usually, the two values are set to 0. If they are set to other values,the RTWP may be abnormally high. To modify the two values, run the SET RFDESPARAMand SET DESENS commands.

Check the attenuation value of the Rx channel

Run the LST RXATTEN MML command. The setting of this parameter affects the gain of theRx channel. If no TMA is available, you do not need to set this parameter. If you set thisparameter, the RTWP is abnormally low. If a TMA is available but the parameter is not set,the RTWP is abnormally high. You need to set the RXATTEN value according to the gain ofthe TMA.

There are two types of TMAs: 12dB TMA and 24dB TMA. You need to observe thisprinciple: TMA gain = Feeder loss + RXATTEN. To modify this parameter value, run the SETRXATTEN command.

Check whether passive inter-modulation occurs Assume that the main RTWP is abnormally high but the diversity RTWP is normal. In this

case, you can suspect that the problem is caused by passive inter-modulation. It isrecommended that you disable the transmit power first. You may encounter thisphenomenon: The RTWP is raised when the transmit power is enabled, but the RTWP isrecovered to the normal range after the transmit power is disabled. In this case, you needto check the connection of the main feeder.

Check whether the abnormally high RTWP is caused by interference

Describe the RTWP symptom (for example, abnormally high continuously, in rush hours, orintermittently). Describe the RTWP value range.

Then, preliminarily determine whether the problem is caused by any interference (if asimilar waveform appears in all surrounding sites, the network planning personnel need to

handle the problem locally). Check whether the abnormally high RTWP is related to subscribers' behaviors

Observe whether the problem is related to subscribers behaviors if you are sure that thepreceding settings are all normal. If the RTWP is raised, see whether a large number ofhigh-speed packet subscribers access the system.

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Check the configuration

Run the LST RXATTEN MML command.

The setting of this value affects the gain of the Rx channel. If no TMA isavailable, you do not need to set this parameter.

If you set this parameter, the RTWP is abnormally low. If a TMA is availablebut the parameter is not set, the RTWP is abnormally high. You need to setthe RXATTEN value according to the gain of the TMA.

To modify this parameter value, run the SET RXATTEN command.

There are two types of TMAs: 12dB TMA and 24dB TMA. You need toobserve this principle: TMA gain = Feeder loss + RXATTEN.

1. When the RTWP is still abnormally low even if the value is set correctly,collect the log information of the main control board and RRU.

2. Trace the RTWP for 20 minutes, and return the tracing result.

Note: When the RTWP is abnormally low, you do not need to collect theinformation as described in the checklist. You only need to provide afeedback of the data of 1) and 2).

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Enable the tracing of Tx Carrier Power of cells on the RNC LMT, and observe the Tx CarrierPower value. In the following figure, 19% indicates that the downlink Tx Carrier Power

accounts for 19% of the maximum Tx power of the cell when the cell is idle (the maximumTx power of the cell is 43 dBm, and the PCPICH configuration is 33 dBm).

Time Tx Carrier Power Avg Non Hspa Tx Pwr

2010-12-21 10:43:25(80) 19 19

2010-12-21 10:43:26(30) 19 19

2010-12-21 10:43:26(80) 19 19

If the reported Tx Carrier Power is abnormal, you need to check the powerconfiguration of the logical cell in the RNC configuration file, especially whetherthe configurations of the maximum Tx power and pilot power are reasonable.

If the default pilot power is 10 dBm lower than the maximum Tx power (forexample, the maximum Tx power of the cell is 43 dBm and the PCPICHconfiguration is 33 dBm), the pilot power accounts for 10% of the maximum Txpower of the cell. Considering all downlink public channels, the total transmitpower of the cell should be account for 19% of the maximum transmit power if noservice is in process.

If the pilot power is configured to an extremely small value, the transmit powermay be not enough. If the pilot power is configured to an extremely large value,the available power may be not enough or severe interference may occur.

The traffic measurement data on the RNC can include minTCP, meanTCP, and MaxTCP. If

the traffic is measured for a long time, minTCP usually refers to the downlink Tx Carrierpower (35.7 dBm) when the cell is idle. This value is reported by the NodeB baseband tothe RNC. MaxTCP cannot be greater than the maximum transmit power of the cell.

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1. Observe the VSWR alarm, and check the antenna feeder.

Check whether there is a component failure alarm at the RRU side. If a VSWR

alarm occurs, check whether the connector of the antenna feeder is installedproperly. Then, check whether there is any power output at the RRU side by usinga power meter.

2. Trace the RF output power on the NodeB LMT.

3. Rest the RRU first, and see whether it can be recovered. Then, reset the baseband boardand see whether it can be recovered.

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Symptom of UL CE Congestion

1. At the BTS side, an alarm prompts that the system exceeds the License capacity

limit. The reason is that the control item is equal to 0 (number of uplink CEs). 2. The standard signaling tracing shows that there are lots of

NBAP_RL_SETUP_FAIL, NBAP_RL_ADD_FAIL, and NBAP_RL_RECFG_FAIL faults.The reason value is cell-synchronization-not-supported (the License configurationcapability is limited) or UL_radio_resources_not_available (the physical capability ofhardware is limited).

3.The IOS signaling tracing at the RNC side shows that there are lots ofRRC_RRC_CONN_REJ faults.

4. At the RNC side, the traffic measurement data contains theVS.RRC.Rej.UL.CE.Cong record.

Symptom of DL CE Congestion

1. At the BTS side, a user alarm prompts that the system exceeds the Licensecapacity limit. The reason is that the control item is equal to 1 (number ofdownlink CEs).

2.The standard signaling tracing shows that there are lots ofNBAP_RL_SETUP_FAIL, NBAP_RL_ADD_FAIL, and NBAP_RL_RECFG_FAIL faults.The reason value is cell-synchronization-adj-not-supported (the Licenseconfiguration capability is limited) or DL_radio_resources_not_available (thephysical capability of hardware is limited).

3.The IOS signaling tracing at the RNC side shows that there are lots ofRRC_RRC_CONN_REJ faults.

4. At the RNC side, the traffic measurement data contains theVS.RRC.Rej.DL.CE.Cong record.

In case any of the preceding symptoms occurs, it indicates that the BTS CEs are congested.To determine whether CE leakage occurs, refer to the section TroubleshootingProcedure.

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To determine the occurrence time and locate the problem accurately, you should collectthe related information synchronously when the problem occurs.

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If the popup page displays detailed error information, handle the fault as instructed. If noerror prompt is available, check whether the common control items are set correctly.

1. Check whether the number of downlink/uplink CEs exceeds the limit allowed bythe License, and whether the configured value is a multiple of 8.

2. Check whether the configured number of local cells is smaller than the actualone.

3. PA[XXDbm] means the maximum number of local cells in license, then themaximum transmit power does not exceed XXDbm. If the NodeB has a 46dBm celland the control item delivered by the License is 43 dBm, the delivery fails. It is thefirst control item that may be ignored.

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Check whether the local cells are configured correctly

1. The cell type should be consistent with the type of the corresponding sector.

2. The baseband resources of the uplink/downlink resource group to which the cellsbelong should be enough to be allocated to the cells.

3. The cell receiving antenna should be configured while the sectors are established, andthe cell transmitting antenna should be configured when local cells are established. Theconfiguration of the cell transmitting antenna should agree with the transmitting diversitymode in the sector configuration. The transmitting antenna must be configured

4. The maximum transmit power of cells and uplink/downlink frequency should match theRF hardware attributes. You can run the DSP RRUTC MML command to view the RFhardware attributes

Check whether the IQ resources on the RRU link are enough to be allocated formultiple cells

The 1.25G fiber supports 10 uplink IQs and eight downlink IQs. The 2.5G fiber supports 20uplink IQs and 16 downlink IQs.

One 1.25G fiber link can be cascaded with up to eight RRUs, One 2.5G fiber link can becascaded with 16 RRUs.

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Check whether the logical cells are configured correctly

Check the following parameters: Cell scramble, cell frequency, maximum transmit

power of cells, transmission parameters (including AAL2PATH, NCP/CCP, ALCAP,and the transmission parameters of the bottom layer in different transmissionmodes), and public channel. When configuring the frequencies of logical cells andlocal cells, you need to observe the following configuration principles:

The maximum transmit power of logical cells should be equal to or lower than thatof local cells;

The transmission configuration at the RNC side should be consistent with that atthe NodeB side, for example, the VPI and VCI of the AAL2PATH;

The cell parameter configuration at the RNC side should be consistent with that atthe NodeB side.

Query the failure reason by running the DSP CELL command at the RNC side

When the establishment of logical cells still fails even if the configurations arecorrect, provide a feedback of the related information to the R&D department foranalysis.

Check whether the local cells associated with the logical cells are available

If the local cells at the NodeB side are not available, the establishment of logicalcells fails. In this case, analyze the problem as described in the section Fail toEstablish Local Cells .

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Query the current clock status by running the DSP CLKSTAT command. First, check thatConfigured Clock Source is set to Line. Then, check whether Configured Work Mode

is set to MANUAL. If Current Work Mode is set to FAST TRACKING, you can wait for at least half

an hour to observe whether the alarm disappears or is locked. Before delivery,Original DA has been rectified and thus cannot be modified. Center DA iscapable of automatic adjustment, and is usually approximate to Original DA.

If the difference between them is extremely large (at least 500), it indicates thatthe DA is deviated. Therefore, you need to adjust the DA to Original DA or so,and then observe.

%%DSP CLKSTAT:;%%

RETCODE = 0 Succeed.

Current Clock Status

--------------------

Slected Clock Source = LINE

Current Clock Source State = NORMAL

Clock Working State = LOCKED

Center DA = 29914

Current DA = 29909 Original DA = 30847

Phase Discrimination

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Checking the Clock Source

Check whether there is an alarm related to E1 transmission, for example, sliding

frame and abnormally high BER. If yes, solve the transmission-related problem first.

Check whether the clocks of the RNCs are locked. If not, the system surely gives analarm of high frequency deviation of the NodeB. Check whether the 8K clocks ofthe GCU and SCU are normal by running the DSP CLK command.

If a large number of the NodeB clocks cannot be locked but the RNC clocks arelocked (the precision requirement of the RNC clocks is far below that of the NodeBclocks), check the upstream clock of the RNC. Usually, the customer or core-network vendor needs to participate in the work.

If a clock alarm occurs to some the NodeB sites connected to a RNC, checkwhether these the NodeB sites are upwards converged to one transmission device.You need to check whether there is a clock alarm caused by the transmissionequipment.

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Testing and Analyzing the Quality of the Clock Source

Query the result of the clock source quality test. The desirable result is that all

Phase Discrimination Values are 0. It is acceptable if a small number of suchvalues are +1 or -1.

You can adjust Current DA if the following conditions are met:

The frequency deviation of Phase Discrimination Value is less than orequal to 5,

The value is obviously positive-skewed or negative-skewed,

The deviation results are even

The adjustment principle is as follows:

If the sum value of Phase Discrimination Value is obviously positive-skewed,raise the Current DA value.

If the And value of Phase Discrimination Value is obviously negative-skewed, reduce the Current DA value. The step is 10. Every time youmodify the DA value, observe the clock quality until Phase DiscriminationValue is equal to 0 stably.

If Phase Discrimination Value fluctuates greatly, it indicates that theclock source quality is poor and there exists the jitter phenomenon. In thiscase, check the clock source.

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Identifying the Oscillator Fault

If the board oscillator is faulty, the system also gives an oscillator fault alarm.

To troubleshoot the board oscillator, perform the following procedure:

Record the Current DA and Center DA values.

Modify Current DA into 16 by running the MOD CURRDA command.Start the clock source quality test, and test the frequency deviation of theOCXO and IUB source clocks of the main control board once or twice (thetest should last for at least 5 minutes every time).Assume that the testresult isA. Modify Current DA into 4080 (maximum), and conduct theclock quality test by using the preceding method. Assume that the testresult is B.

Criteria:

Calculate the adjustable range by B-A. The computation result may be as follows:

The result is equal to or greater than 15, so the result is basically normal.

The result is 15 to 10. Record the result. It is not a serious problem.

If the result is smaller than 10, it indicates that the OCXO is faulty.

If you determine that the OCXO is faulty, you can replace the faulty board. If youdetermine that the oscillator is basically normal or no serious problem occurs butyou still fail to lock the clock by adjusting the DA value, provide a feedback of the

information and the preceding results to the Huawei R&D department for analysis.

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Checking the Connection of Optical Module

1. Check whether the optical module is loosened. Remove the optical module and inset the

optical module again. 2. View the vendor information in the label of the optical module. It is recommended that

the optical modules at two ends of the fibers are from the same vendor.

3. For the RRU cascading scenario, check the interfaces of all cascaded optical modules.

Checking the Fiber Connection

1. Check whether the connection between the fiber and optical module is tight andreliable. Remove the connector and then insert the connector tightly.

2. Check the fiber quality. Check whether the fiber is extremely bent. The fiber may bebroken if the bend radius is extremely small. Test the fiber quality and check its agingdegree by using an optical power meter.

3. Replace the poor fiber with the normal fiber.

4. For the RRU cascading scenario, check all cascaded fibers. check all cascaded fibers. Checking the Optical Module of the RRU through the Local Loopback Operation of the Fiber

1. Arrange a normal test fiber.

2. Connect two ends of the test fiber to the same optical module of the RRU.

3. Press the TST_CPRI button in the maintenance cavity of the RRU, as shown in thefollowing figure:

4. View the indicator status of the corresponding port in the maintenance cavity of the RRU(for example, view the status of the CPRI_W indicator in the RRU maintenance cavity if twoends of the fiber are plugged to the CPRI_W port of the RRU at Step 2). If the CPRI_Windicator is green, it indicates that the RRU and the optical module plugged on the port arenormal. If the CPRI_W indicator is red, it indicates that the RRU or the optical moduleplugged on the port is abnormal.

5. If the CPRI_W indicator is red at Step 4, replace the faulty optical module. Repeat Steps 2to 4. If the CPRI_W indicator is still red, it indicates that the interface of the optical moduleat the RRU side. Replace the RRU.

6. For the RRU cascading scenario, check all cascaded RRUs, and check all cascaded fibers.

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Symptom

Sleeping Cell has the following features:

The cell status is normal

No BTS alarm is generated

All channels/resources in the cell are unavailable, cannot be provided

You need to enable RNC IOS signaling tracing or Uu interface tracing, and observewhether a Uu interface message of the cell is reported, thus analyzing the problempreliminarily.

The Sleep Cell problems are categorized into the following types and are numbered asfollows:

SLC-Q1: The downlink signals are abnormal or the downlink scramble cannot be

detected. SLC-Q2: The RRC Connect Request message is not reported.

SLC-Q3: The RRC Connect Setup Complete message is not reported.

SLC-Q4: The RB Setup Complete message is not reported.

The following two phenomena are normal and cannot be considered to be Sleeping Call:

1. In a desert area under coverage, there are no subscribers in the most time. It isnormal that there are some subscribers once in a while.

2. In the multi-carrier scheme, some carrier cells are always barred, and the DRDhierarchically switches the services to these cells.

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Check the status of the RNC cells

Run the DSP CELL command in the RNC LMT and query the execution result. If the cellstatus is abnormal, it indicates that the Sleeping Cell problem does not occur. If the cellstatus is normal, proceed to the next step.

Check whether the cell is barred

Run the LST CELLACCESSSTRICT command in the RNC LMT and query the executionresult. If the cell is barred, it indicates that the Sleeping Cell problem does not occur. If thecell status is normal, proceed to the next step.

Check the cell radius

Run the LST LOCELL command in the RNC LMT and query the execution result. If the cellis extremely small, access fails in the area beyond the cell radius, which is not a SleepingCell problem. If the cell status is normal, proceed to the next step.

Check the alarm shield of the NodeB

Run the LST OBJALMSHLD: QRMD=AID command in the NodeB LMT. Check whetherthe execution result shields from some important alarms. If the alarm shield is disabled and

the alarm is reported, process the alarm emphatically. If the execution result does not shieldfrom any alarm, proceed to the next step.

Check the AAL2PATH configuration (the transmission mode is ATM)

Check whether the AAL2PATH configuration on the RNC is consistent with that on theNodeB. If not, the problem is not a Sleeping Cell problem and thus you need to modify theAAL2PATH configuration to ensure the consistency between them. If yes, proceed to thenext step.

Check the status of the NodeB cells

Run the DSP LOCELL command in the NodeB LMT and query the execution result. If thecell status is abnormal, it indicates that the Sleeping Cell problem does not occur. If the cellstatus is normal, proceed to the next step.

Check the VSWR

Run the DSP VSWR command in the NodeB LMT. Query the VSWR of the RRU. If the

VSWR is lower than 10 (illegal), it indicates that the RRU is faulty. When the VSWR reachesthe VSWR threshold, the system reports a user alarm of SASU VSWR Abnormal.

If you do not find any problem at the preceding steps, collect and return the related information tothe R&D department for analysis.

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P-56WCDMA NodeB Troubleshooting

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Owb404400 Nodeb Wcdma v200r011 Troubleshooting Issue 1.00