BBU CPRI Optical Interface Performance Degraded

BBU CPRI Optical Interface Performance Degraded

This alarm is reported when the TX/RX performance of the optical module on the CPRI port of the BBU deteriorates.

When the TX/RX performance of the optical module deteriorates significantly, the quality of services carried on the CPRI link of the RF units may decrease significantly, or the ongoing services carried on lower-level RF units may even be disrupted.

Reasons for fault:

?The optical module or connector of the BBU is improperly installed. Or the optical module is aged.

?The optical connector on the CPRI port of the BBU is dirty.

?The optical module on the CPRI port of the BBU is not supported by the BBU, in terms of type (single-mode or multi-mode) and rate.

?The optical module or connector of the lower-level RF unit is improperly installed. Or the optical module is aged.

?The optical connector of the lower-level RF unit is dirty.

?The optical module on the CPRI port of the lower-level RF unit is not supported by the lower-level RF unit, in terms of type (single-mode or multi-mode) and rate.

?The optical fibers between the BBU and the lower-level RF unit are bent, deformed, or worn-out, or too long (longer than 40 km), which leads to a high attenuation of optical signals.

First of all, we need to check the RRU is getting power or not.

we also need to check the voltage in power cable by Multimeter, it must be minimum -48V DC.

If RRU is not getting the power, we need to change the RRU

If RRU is getting power then we need to check the CPRI cable.If the alarm is in cell B,then we can interchange the cpri cable with cell A(from both GTMU and RRU),if the alarm is shifted to Cell A,then the problem was in CPRI cable.So we need to change the CPRI cable.