What is the CPRI? How can solve its Alarm ?

CPRI is the Common Public Radio interface and use to transmit / receive the data between RRU & BBU (Base band Unit )

L = LTE → Long Term Evolution and this a standard for 4G Mobile Communication Services

U = UMTS → Universal Mobile Telecommunication System and this a standard for 3G Mobile Communication Services

G=GSM → Global System for Mobile communications and this a standard for 2G Mobile Communication Services

① BBU CPRI Interface Error Alarm:

Description of Alarm:  The alarm is generated when the interface (((CPRI Cables))) between the BBU & RF Units are malfunction

·        CPRI Interface Initialization Failure

·        CPRI Interface Transmit Error

·         CPRI Interface Receive Error

Possible Causes of Alarm:

1.      The Optical Module is Faulty

2.      The Optical Fiber Cables are destroyed

3.      The Optical Module maybe improperly installed in BBU / RRU

4.      The Optical Fiber’s Connector is Faulty

5.      HW is Faulty ( BBU / RFU )

6.      Inner BBU Connection is Faulty

7.      Data Configuration is incorrect

·        Cabinet Number

·        Sub-rack Number

·        Slot Numder

·        Port Numder

·        Board Type

8.      If the Transmission is electrical , Check the above too

Procedure of Troubleshooting:

v Check physical Connection Between BBU & RRU

v Check the inner BBU Connection

·        Run the Command LST RRUCHAIN to check the inner of BBU Connection & provides the
number of pins that hold the Port

·        Run the Command LST RRU/DSP RRUCHAINPHYTOPOto Check the Configuration work Mode for RFU &
Verify the main Control Board if there are dual-Modes operation

·        Run the Command LST SOFTWAREto check Software Version of dual Modes & which SW Mode supports the inner-BBU Connection(( and Ensure that dual Modes are support the inner-BBU Connection  ))

v Verify the Configuration and guarantee that it is applicable with the Design

v Check the Status of Cables

·        Run the Command DSP SFP to Check the status of Cables

·        Make loopback by closing TX & RX ports of an Optical Module in the BBU …then remove the Loop after checking

v Reset the BBU by using the Command RST BRD  to reset the BBU interconnection and Please wait until the board is restarted

v Replace the faulty board for BBU interconnection if any.

Goodluck! Walid Nawar