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HUAWEI TECHNOLOGIES Co., Ltd. HUAWEI Confidential
LTE Hardware Operation and Maintenance
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Chapter 1 BBU Architecture
Chapter 2 Hardware Fault Alarms
Chapter 3 Indicator Functions
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BBU Architecture – Logical Relationships Between Different Systems
控及时钟模块
Back plane
BBI
MPT
BBP RFU
TRP
LMILMT
RRU
Control plane
INUSCU
CLKIHigh-speed user
CIU/EXU
CLKI
PWRFAN
BBU interconnection
Controller
BBP
BBIs and BBPs run on the same type of board and the availability of CPRI ports on these boards depends on their slot numbers.
An MPT board provides clock, transmission, and operation and maintenance functions.
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FAN
SLOT0(BBP, TRP, SCU, and CIU) SLOT4(BBP, TRP, SCU, and CIU)
POWER0
SLOT1 (BBP, BBI, TRP, SCU, and CIU) SLOT5(BBP, TRP, SCU, and CIU)
SLOT2(BBP, BBI, TRP, SCU, and CIU) SLOT6(MPT, EXU, SCU, and TRP)
POWER1
SLOT3(BBP, BBI, TRP, SCU, and CIU) SLOT6(MPT, EXU, SCU, and TRP)
BBU Architecture – Slots of Main Control and Baseband Boards
In most cases, MPTs are inserted
in slots 6 and 7 and work in
active/standby mode. In dual-
mode scenario, they can be
configured to work in active/active
mode.
The system has eight board slots, two power supply slots, and a fan slot.
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BBU Architecture - LBBPc Board Structure
Module Function
CPU small system module
Key service channel and control center
Baseband processing module
Consists of the FPGA and DSP. The DSP performs uplink service processing based on algorithms.The FPGA performs uplink and downlink baseband processing, encrypts data, and performs CPRI framing.
Control logic module
Watchdog, resetFPGA loadingIOBUS transparent data transmission
CAN moduleMonitors and manages boards
Clock moduleManages the clock resources of boards
Power supply module
Controls the sequence for supplying boards with power and for powering on the boards
RapidIO Switch module
Responsible for data exchanges between chips
JTAG module Debugs and loads software
CPU
DDR2 DDR2DDR2 DDR2 DDR2 DDR2 DDR2 DDR2
SFPGE
FLASH CPLD
RS
T
GP
IOSGMII 1
SGMII 2
SGMII4
IDX1IN
T
IO BUS
JTAG
DDR2
UART
FPGA0
BSBGPIO
SG
MII
0
IO BUS
FPGA1
CLK
POWER
DSP 0
DSP 1
DSP 2SGMII 7
SGMII 6
SGMII 5
66 . 67 M CORE
125 M SGMII
125 M SRIO
V33V25V18VA10
V09 COREV09 VTT
RIOSW
UA
RT
RIO1*1X
232
PHY
SG
MII
3
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BBU Architecture – LBBPd Architecture
pan
el
CPU
bac
kbo
ard
ASIC A
FPGA
RIOSW
ASIC B
LCPRI*3 3.072G
MPT—> CPU IDX1
HDLC
SGMII*1
LBUS*2 4.9152G
uart, rsv_io
DBUS 8bit*122.88M
1
2
2
3
4
2
maintenance: GE*1
CPU_SRIO 3.125*4
SRIO*4 operation
reserve HDLC
CPRI extend
SGMII*2 encrypt
SRIO*1 load &maintenance
CPRI*6
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BBU Architecture – Main Control Boards Working in Active/Standby Mode
SWITCH (active)6#
SWITCH (standby)7#
BBI/BB/TRP0#
BB/TRP2#
BB/TRP3#
BB/TRP5#
BBI/BB/TRP
1#
BB/TRP4#
MPT CPU (active)
MPT CPU(standby)
GMII/RGMII GMII/RGMII
1 2 3 4 5 6
7
123456
7
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BBU Architecture – Signal Transmission on the Main Control BoardTransmission directions of signals on front panels
The red lines indicate the transmission directions of signals at electrical ports.The green lines indicate the transmission directions of signals at optical ports.After the FPGA receives four input signals, it chooses two of them to send out to lower-level devices.
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Hardware Fault Alarms
Troubleshooting guideline
1. Refer to the alarm online help to clear the alarm.
2. As an alternative, refer to the error locating guide to clear the alarm based on the
symptom. To view the error locating guide, visit http://support.huawei.com and choose
LTE TDD -> LTE TDD eNodeB -> Technical Guides -> Troubleshooting Guide.
3. Collect logs to assist in error locating. The commands for collecting one-click logging
files (brdlog) of each board are similar. The only difference lies in their cabinet,
subrack, and slot numbers.
A hardware error is difficult to locate without log and
serial port information, or even hardware test tools.
The customer or onsite engineers are required to be
capable of identifying a hardware error and then
replace the faulty board.
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Hardware Alarm - 26205
Problem 1 ALM-26205 BBU Board Maintenance Link Failure
Symptom: The service channel between a baseband board and the main control board is disconnected and
there is a high probability that an alarm such as ALM 26200 Board Hardware Fault of ALM 26203 Board
Software Program Error is reported. If an alarm is reported, clear the alarm first.
Troubleshooting:
1. Power off the board that is reporting on the alarm. Then power on the board by running OPR BRDPWR.
Check whether the fault is rectified.
2. Reset the main control board by running RST BRD.
3. Remove the board that is reporting the alarm and check whether the pins on the connectors between the
board and the back plane are inserted properly. If they are inserted properly, insert the board to the
subrack again and check whether the fault is rectified.
4. Replace the baseband board.
5. Remove the main control board. Check whether the connectors between the main control board and the
back plane are inserted properly. If yes, insert the main control board and check whether the fault is
rectified.
6. Replace the main control board.
7. Replace the back plane.
Note: If the fault is not rectified after board replacement, the board is not faulty and do not treat it as a
damaged board.
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Hardware Alarm - 26200/26234
Problem 2 ALM-26200 Board Hardware Fault
Root cause: The power supply, clock, or temperature of a board is abnormal.
Troubleshooting:
1. If the alarm is automatically cleared within 10 minutes and is no longer reported, the alarm is a false alarm
mistakenly reported during automatic software restoration. In this case, no hardware fault occurs and
troubleshooting is not required.
2. If the alarm persists for longer than 10 minutes, power off the board and then power on it. If you are at the site, pull
out the board and then insert it. If you are at the remote end, run OPR BRDPWR.
3. Check the indicators on the board panel at the site. If the RUN indicator is steady on, pull out the board and then
insert it to another slot. Check whether ALM-26200 is reported.
4. Replace the board.
Problem 3 Alarm ID: 26234 BBU CPRI Interface Error
Root cause: An error occurs when CPRI data is exchanged between the BBU and RRU over a CPRI link (link layer).
Troubleshooting:
1. Run DSP SFP to query the optical power of the optical module between the baseband board and the optical module.
Make sure that the optical power falls on the normal range.
2. Reset the RRU and the baseband board, and check whether the fault is rectified.
3. Use an optical power meter to check whether the optical module and optical fibers between the BBI and RRU are
working properly.
Note: To find the root cause in a timely manner, it is recommended that both qualified and faulty optical fibers be used
for cross testing.
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Hardware Alarms - 26232/26201
Problem 4 ALM-26232 BBU Optical Module Transmit/Receive FaultSymptom: An error occurs when optical signals are exchanged between the BBU and RRU over an optical
link (physical layer).
Probable causes:
1. Optical fiber connectors on optical modules or optical modules of the baseband board are loosely
connected or the optical modules are faulty.
2. Optical fiber connectors on optical modules or optical modules of the RRU are loosely connected or the
optical modules are faulty.
3. Optical connectors on the ports used for the BBU to connect to lower-level radio frequency units are not
clean.
4. The working mode (single-mode or multi-mode) of optical modules is different from that of optical fibers.
5. The transmission rate of the optical modules on the baseband board is inconsistent with that on the RRU.
6. The optical connections between the BBU and the RRU are interrupted.
7. The RRU is faulty or is not powered on.
Perform troubleshooting by checking whether the problem is due to one of these causes.
Problem 5 ALM- 26201 Board Memory Soft FailureRoot cause: Part of data in the memory of the board is overwritten due to external electromagnetic
interference or radiation.
Troubleshooting:
1. Run RST BRDPWROFF to power off and then on the board.
2. Reset the main control board in slot 7.
3. Replace the board.
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Hardware Alarm - 26104
Problem 6: ALM-26104 Board Temperature Unacceptable
Root cause: The board temperature is out of the normal range.
Troubleshooting:
1. If only one board reports this alarm, run DSP BRDTEMP to check whether the temperature of
the board is higher than 85 . In addition, check whether temperatures of the boards in other ℃
slots fall on the normal range.
2. If the temperatures of all these boards are normal, the temperature sensor of the board
reporting this alarm may be faulty. In this case, the alarm is a false alarm mistakenly reported
by the board. Replace the board or ignore this alarm.
3. Check the temperature of each board in the BBU subrack. If the temperatures of all these
boards are higher than 85 , check whether a fan fault alarm is reported.℃
4. Check whether the BBU subrack is positioned in a high-temperature environment. If yes,
place it in a position where ventilation is good.
5. Check whether the air vent on each side of the BBU is blocked.
6. Check whether the three fans in the fan frame have stopped rotating.
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Hardware Alarms - 26216/26204
Problem 7 ALM-26216 Board Not Securely Installed
Root cause: The pins between the board and the back plane are not inserted properly.
Troubleshooting:
1. Remove the board and then insert it again. Check whether the fault is rectified.
2. Remove the board and check whether any pin on the back plane is bent, fallen, or damaged. If any pin is
bent, fallen, or damaged, replace it.
3. Insert the board into another slot. Check whether ALM-26216 is reported. If yes, replace the board.
Problem 8 ALM-26204 Board Not In Position
Cause: The main control board detects that a board is not in position.
Troubleshooting:
1. Check whether the connectors between the board and the back plane are inserted properly.
2. Insert the board again and make sure that the board is properly connected to the back plane through
connectors.
3. Insert the board into another slot and check whether ALM-26204 is reported.
4. Replace the board.
5. Remove and then insert the main control board that is in the same subrack as the faulty board.
6. Replace the main control board that is in the same subrack as the faulty board.
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Indicator Functions
Label Color Blinking Frequency Meaning Remarks
RUN Green Steady on The power supply is normal but the board is faulty.
After the system is powered on, the RUN indicator is steady on. If the secure version is in use, the RUN indicator blinks at the frequency of 4 Hz. If the board starts properly, the RUN indicator blinks at the frequency of 0.5 Hz.
Steady off The board has no input power or is faulty.
At the frequency of 0.5 Hz (on for 1 second and off for 1 second)
The board is running properly.
4 HzThe board is loading software or being configured, is not started, or is running in a secure version.
ALM Red Steady on An alarm is reported and the board needs to be replaced.
The system can be configured to or not to turn on this indicator when a software or configuration error occurs. The configuration is up to the product line.
At the frequency of 0.5 Hz (on for 1 second and off for 1 second)
An alarm is reported and it cannot be determined whether the board needs to be replaced. The alarm may be caused by a board or interface error.
Steady off No error
ACT Green Steady on The board is working in the active state.
1. In dual-mode applications, both the main control boards work in active mode. If this indicator is blinking at the frequency of 4 Hz, the board is an active main control board.
2. During tests, this indicator is on only when the board is working in the active mode.
Steady off
The board does not provide services because it is not working in the active state or the software running on it has not been activated. For example, the board has not been configured or has been manually blocked.
At the frequency of 4 Hz OML link disconnection
At the frequency of 0.5 Hz (on for 1 second and off for 1 second)
The board is being tested. For example, a USB flash drive is used for an RRU VSWR test. If an upgrade is carried out using the USB flash drive, this indicator does not indicate it.
At the frequency of 4 Hz (blinking for 2 seconds and then off for 2 seconds)
The service is not ready. For example, the cell or service link is not ready or a fault that requires onsite troubleshooting occurs.
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Indicator Functions
Label Color Blinking Frequency Meaning Remarks
CPRIxRed or green
On (green) CPRI links are connected and normal.
On (red)
The optical module fails to receive or send data. Examples of the possible causes:− The optical module is faulty.− The optical fiber is disconnected.
Blinking in red at 4 Hz The RRU connected over the CPRI link has a hardware error.
Blinking in red at 0.5 Hz
− CPRI unlock because dual-mode clocks are mutually locked or the transmission rates at the CPRI interfaces do not match each other. To solve this problem, rectify system configurations.
− The RRU connected over the CPRI link reports a VSWR alarm because a test is being carried out using USB flash drives.
OffThe SFP module is not in position or the optical module is powered off.