Troubleshooting Typical Problems for SDR Deployment

CDMA Technical Support Department

Troubleshooting Typical Problems for SDR Deployment

Version Date Author Reviewer Remarks

V1.0 2009-01-05 Not open to third party

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. I

© 2008 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information of the document is subjected to change without notice.

Contents

1 WAYS TO CHECK WHETHER RRU IS POWERED ON.................................................1

1.1 METHOD 1.....................................................................................................1

1.2 METHOD 2.....................................................................................................1

1.3 METHOD 3.....................................................................................................2

1.4 METHOD 4.....................................................................................................2

2 CHECKING STATUS OF OPTICAL LINK.......................................................................2

3 OMC ALARM: OPTICAL MODULE INDICATOR OFF, RTR NOT DETECTED.............2

3.1 TOOLS...........................................................................................................2

3.2 TROUBLESHOOTING PROCEDURE...........................................................3

4 OMC ALARM: RTR NOT DETECTED (RLS INDICATOR OF THE FOREGROUND FS BOARD FLASHES NORMALLY AND THERE IS NO FS ALARM IN OMC)..................4

5 BBU FAILS TO START BECAUSE OF E1 PROBLEM...................................................5

6 BBU FAILS TO POWER UP BECAUE OF PROBLEM OF PM POWER SUPPLY.........6

6.1 TOOLS...........................................................................................................6

6.2 TROUBLESHOOTING PROCEDURE...........................................................6

7 CC (ON BBU) FAILS TO POWER UP WHILE PM/SA/FA POWER UP NORMALLY....6

8 FAULT OF PA DISABLING (LOW POWER ALARM/AUTO CALIBRATION FAILURE/VSWR ALARM)................................................................................................7

9 GPS RECEIVER FAULT...................................................................................................7

10 alarm of Optical module not in position..............................................................................8

II © 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

List of Figures and Tables

Figure 1 RRU Concatenation Optical Port................................................................................1

Figure 2 GPS Voltage Measurement.........................................................................................8

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. III

1 WAYS TO CHECK WHETHER RRU IS POWERED ON

Figure 1 RRU Concatenation Optical Port

1.1 Method 1

After the RRU is connected to power, a clear click sound will be heard if the device is powered on. This method does not apply if the RRU is installed on the tower as the sound cannot be heard in that case.

1.2 Method 2

After the RRU is connected to power, uncover the RRU’s concatenation port and see if there is light inside the RRU chamber. If yes, this means the device is powered on. If there is an optical module, do not look at the optical module directly. The light can be seen from this interface even if the optical module is there. But the optical module can also be extracted if necessary.

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. 1

SDR基站开局常见故障解决方法

1.3 Method 3

Some time after the RRU is connected to power, touch the RRU’s shell and now if the shell feels a little heated, this means the device is already powered on. However, the shell may feel hot because of the sunshine.

1.4 Method 4

Use a clamp meter to measure either the 48V or 48VGND power line. Any measured current indicates the RRU is powered on successfully. Remember NOT to clamp both the 48V and 48VGND power line to test the current. The problem is, however, the clamp meter is often unobtainable.

2 CHECKING STATUS OF OPTICAL LINK

Use a tester that can test the 1310nm and 1550nm optical intensity to test the optical intensity of BBU’s and RRU’s Rx end. The allowed optical power ranges the following:

10KM optical module: -3dBm ~ -18dBm (Rx optical power); 5dBm ~ -10dBm (Tx

optical power).

40KM optical module: -3dBm ~ -20dBm (Rx optical power); 0dBm ~ -5dBm (Tx

optical power).

80KM optical module: -3dBm ~ -20dBm (Rx optical power); 2dBm ~ 0dBm (Tx

optical power).

The optical link must be faulty if the tested optical intensity fails the allowed range.

3 OMC ALARM: OPTICAL MODULE INDICATOR OFF, RTR NOT DETECTED

3.1 Tools

Two self-loop test optical fibers and at least two optical modules.

Optical fiber and optical module for connecting BBU with RRU (spare parts for commissioning).

2 © 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

3.2 Troubleshooting Procedure

It should be noted beforehand that the communication between BBU and RRU works in the following mode:

BBU(FS) ->optical port optical module->optical fiber->RRU optical port

optical module-> RRU;

If during BBU + RRU deployment, the foreground and background are powered on successfully and the communication between foreground and background is normal, but the OMC shows such alarms that the optical module indicator is off and RTR fails to be detected, we can locate the fault with the following methods:

Check whether RRU is powered on or not. Refer to Chapter 1 Ways to Check Whether RRU Is Powered on.

Check whether the optical link is normal. Refer to Chapter 2 Checking Status of Optical Link.

At the foreground, extract and insert the BBU optical port optical module again or the optical fiber at both ends, so as to make sure the optical module and optical fiber are well in position.

Check whether the BBU optical port optical module is normal or not:

Checking the optical port module: Use a prepared optical fiber to make the FS optical module self loop and observe the status of the RLS indicator. If the RLS indicator flashes normally, it means the BBU is normal; otherwise replace the optical module or FS board. (Note: The reverse link from RRU to BBU, not necessarily the forward link from BBU to RRU, is normal if the RLS indicator flashes normally after BBU and RRU are connected with the optical fiber).

Checking the optical network: Loop back from the end of the optical fiber on the RRU side to the BBU. Observe the status of the RLS indicator. The optical link is normal if the RLS indicator flashes normally. Check whether any alarm of the BBU’s CHV and FS board exists (especially the “BDS link fault” alarm of CHV, and the “Optical port optical module not in position” alarm (to be determined), the “Optical port optical module indicator off” alarm and the “Optical port reverse frame unlocked” alarm of FS). (name of the alarms are to be determined). If no such alarms exist, it means the transmission works fine. If any of the alarms exist, the transmission may have some problem and in this case, it is necessary to locate any fault of the optical transmission network.

Disconnect power and connect the FS board to power again through OMC operations .

Replace the optical fiber for BBU_RRU communication with a prepared or spare one.

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. 3

SDR基站开局常见故障解决方法

Replace the whole RRU device if none of the previous operation helps.

4 OMC ALARM: RTR NOT DETECTED (RLS INDICATOR OF THE FOREGROUND FS BOARD FLASHES NORMALLY AND THERE IS NO FS ALARM IN OMC)

Such alarm indicates that the reverse link from RRU to BBU is normal. The forward link may be faulty or the RRU has some problem. Way to locate the fault:

1 Check whether the forward link is normal:

1) At the foreground, extract and insert the FS optical port optical module again or the optical fiber at both ends, so as to make sure the optical module and optical fiber are well in position.

2) Self loop to make sure the optical module and optical network are normal.

Checking the optical port module: Use a prepared optical fiber to make the FS optical module self loop and observe the status of the RLS indicator. If the RLS indicator flashes normally, it means the BBU is normal; otherwise replace the optical module or FS board. (Note: The reverse link from RRU to BBU, not necessarily the forward link from BBU to RRU, is normal if the RLS indicator flashes normally (see Comments for indicator definition) after BBU and RRU are connected with the optical fiber).

Checking the optical network: Loop back from the end of the optical fiber on the RRU side to the BBU. Observe the status of the RLS indicator. The optical link is normal if the RLS indicator flashes normally. Check whether any alarm of the BBU’s CHV and FS board exists (especially the “BDS link fault” alarm of CHV, and the “Optical port optical module not in position” alarm (to be determined), the “Optical port optical module indicator off” alarm and the “Optical port reverse frame unlocked” alarm of FS). (name of the alarms are to be determined). If no such alarms exist, it means the transmission works fine. If any of the alarms exist, the transmission may have some problem and in this case, it is necessary to locate any fault of the optical transmission network.

3) Disconnect power and connect the FS board to power again through OMC operations

4) Replace the optical fiber for BBU_RRU communication with a prepared or spare one.

2 Check the version of RTR in OMC

4 © 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

1) In OMC, initialize and query the version of RTR.

2) In OMC, download the correct RTR version.

3) In foreground, download the RTR version.

4) Replace the whole RRU device if none of the previous operation helps.

Please note that if several RRUs are connected on site, it’s advisable to switch the optical links of the RRUs to cross-check the optical modules and optical links.

5 BBU FAILS TO START BECAUSE OF E1 PROBLEM

The foreground symptom when the E1 link between BBU and BSC has a problem is like this: After the BBU is powered up and some time after the CC board gets started, the ES0 indicator on the panel of CC board flashes, the MS/REF indicator is constantly ON, the ALM indicator turns OFF and finally the RUN indicator is constantly ON. Several minutes later, the CC board still has no response and then it is reset (the ALM and RUN indicators flash).

1 Perform an E1 loop back test before the E1 transmission cable connects with BBU, to make sure the E1 transmission from the BBU site to BSC works fine without error code (error code cannot be detected in the loop back test).

2 Observe whether the E1 indicator is normal on the CC board’s panel (ES0 0~3 E1 links; ES1 4~7 E1 links). Connect the E1 link 0 and now the ES0 indicator should flash in normal cases.

3 Check the sequence of E1 cables. From the DB44 interface, the E1 cable goes in two branches, eight cables each (four first links and four later links). The cable of E1 link 0 is often labeled. Make sure the E1 link 4 is not used as E1 link 0 by mistake (if it is mistaken, the ES1 indicator on CC panel flashes).

4 Extract the SA board to check whether the Abis_ModeID and BDS_ID jumpers are in correct state (in the case of a single frame and 75 ohm, these E1 jumpers do not need the cap for short circuit connection).

5 Check whether the E1 connector is in normal state, if high error code ratio is found to be caused by a reason other than the transmission problem.

6 Extract and insert the panel cables again to the SA board, or extract and insert the CC board again. If none of these operations helps, replace the transfer cable of the SA board or the SA board itself.

7 Replace the whole BBU device if none of the previous operation helps.

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. 5

SDR基站开局常见故障解决方法

6 BBU FAILS TO POWER UP BECAUE OF PROBLEM OF PM POWER SUPPLY

6.1 Tools

Tailor-made PM serial cable.

MCU versions of all boards.

6.2 Troubleshooting Procedure

1 Extract the PM board from the frame and power it up. Observe the indicators on its panel.

1) The PM is normal if its RUN indicator flashes normally.

2) If RUN and ALM indicators flash quickly at the same time, the PM may have a version problem and the test version is used. Now use the PM serial cable to download the formal version of PM from the foreground. The version cannot be distributed from the OMC for the moment because the whole BBU device cannot be powered up yet.

2 If the PM can be powered up normally (as shown by the RUN indicator) after it is extracted from the frame, but the whole BBU fails to be powered up by the inserted PM module, the power supply of the PM must be faulty. Replace the power board of PM.

7 CC (ON BBU) FAILS TO POWER UP WHILE PM/SA/FA POWER UP NORMALLY

1 Extract and insert the CC board again.

2 Extract and insert the PM power board again.

3 Replace the CC board or PM board.

4 Replace the whole BBU device if none of the previous operation helps.

6 © 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

8 FAULT OF PA DISABLING (LOW POWER ALARM/AUTO CALIBRATION FAILURE/VSWR ALARM)

Please refer to the RF troubleshooting.

In the process of cutover, the connector problem of antenna feeder may result in VSWR alarm which in turn leads to PA disabling. The PA disabling usually comes with the low power alarm, carrier low power warning and auto calibration failure. The reason for PA disabling may fail to be found in the current alarm record due to the problem of alarm mechanism employed at present. We can do the following to locate a fault of PA disabling:

1 In the RF control of dynamic management, manually stop the auto calibration so as to avoid repeated auto calibration caused by VSWR alarm while the RRU is powered up for the first time.

2 Query whether there is VSWR alarm in history alarm.

3 Double click the alarm of auto calibration failure and see whether there is reason description indicating that the auto calibration failure is caused by VSWR alarm.

4 In the RF control of dynamic management, manually start the auto calibration and see whether the operation is successful. If the calibration fails, check whether there is VSWR alarm reported in the process of auto calibration.

5 The antenna feeder interface of RRU is labeled with RX/TX (main antenna) and RX (diversity antenna). The difference should be noted while the antenna feeder is being installed. If a VSWR alarm is reported, switch the antennae and check the alarm. Now if the alarm disappears, it indicates the original RX/TX connector of the main antenna has a problem and it should be made again.

9 GPS RECEIVER FAULT

1 In OMC, check the information attached with the “GPS receiver fault” alarm and see whether it is a problem of open circuit or short circuit of GPS antenna feeder.

2 Problem of GPS open circuit/short circuit. Note that on the CC panel, the voltage between the copper core of the GPS connector and the enclosure is about 5.3V. Check whether each segment of GPS connector cable and GPS lightning arrestor connection are normal.

3 At the foreground, do the following checks:

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. 7

SDR基站开局常见故障解决方法

1) Extract the CC board and check whether the RF feeder from the CC panel to the SMA connector inside the board is connected well.

2) Check whether the soft feeder copper core from the CC panel to the GPS lightning arrestor is open circuited (or whether the copper core is shorted circuited with the enclosure).

3) Check whether the copper core of GPS lightning arrestor I/O is open circuited (or whether the copper core is shorted circuited with the enclosure).

4) Check whether the feeder connector of the GPS mushroom head is correctly installed and connect it to the CCP board to be powered up. Measure the voltage between the connector at the mushroom head side and the enclosure. The voltage should be approximately 5.3V.

5) Check whether the feeder connector of the GPS is made correctly and make sure the feeder and GPS lightning arrestor are connected with the CC board correctly. Replace the reception antenna of the GPS mushroom head if necessary.

Figure 2 GPS Voltage Measurement

Take the cable off and measure the voltage between the GPS connector copper core and the enclosure, which should be approx. 5.3V

8 © 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

10 ALARM OF OPTICAL MODULE NOT IN POSITION

1 Make sure in OMC that the FPGA and CPU versions of the FS board are correct. Compare the versions with those of the sites that are working fine if necessary.

2 Configure the optical module to other optical port and see if now the alarm disappears. For example, switch the optical module to optical ports 3~6 of the FS board. If the alarm persists, it’s recommended to replace the optical module first (if no spare board is available, take the optical module off the RRU for a test).

3 Replace the optical module and test the module on all six optical ports on the FS board.

4 Replace the FS board if none of the above operations helps.

ZTE Confidential Proprietary © 2008 ZTE Corporation. All rights reserved. 9