LTE Cell KPI Degradation – Possible Causes?

Hi friends!

Have you ever experienced a sudden degradation of all KPIs in an LTE cell (Ericsson) that was not caused by:

  • Off-baseline parameters
  • Missing neighbors
  • PCI conflicts
  • Physical issues or alarms

I have already reset the Baseband and the RRU, and the other cells on the same site are not affected.

Could this still be a Baseband failure, or should I investigate other potential causes?

What is the cause of the failure, and which vendor equipment is involved?

At Ericsson.

All KPIs have degraded, including accessibility, mobility, and retainability.

In Nokia, I have often encountered this hanging issue in 80% of cases.

A reset usually improves the situation, but in some cases, R&D team intervention is required, and the root cause is found to be a hardware fault.

You need to dig deeper to identify the failure cause, as it may provide some indication. If not, involving other teams for further investigation is necessary.

Try analyzing accessibility failure causes, as they might give you a useful hint.

Ok, I will check. Thanks!! :+1:t4::+1:t4:

Based on experience, this type of degradation is often caused by either the Baseband (BB) unit or the RRU.

As an initial action, try resetting the BB if you haven’t already, especially if the degradation affects all cells. If the issue is isolated to a single cell, then reset the RRU if you haven’t done so yet.

What are the RSSI levels?

The RSSI levels are within normal ranges… :cold_sweat:

I suggest first checking whether the issue is at the sector or NodeB level.

  • If it’s a sector issue, check VSWR/feeder conditions.
  • If it’s at the NodeB level, investigate transport issues.
  • Also, check for missing neighbors and RRC failures as an initial step.

If you have a CV saved before resetting the BBU, please roll back to that configuration.

Have you checked if any changes have been implemented?

Are the KPIs of other cells stable?

Also, verify the VSWR value.

sometimes DSCP Marks on transport layer are different (access, Aggregation, IP core, Core), and cause this kind of degradation.