Swap in LTE site causing degradation

Dear Experts,
An interesting case I want to share with you:
On field I get swap on site in LTE, but if remove swap we found degration in KPIs.
All parameter are audited.
Vendor is ZTE.

Any suggestion?

Please check if you have any PCI Collison/confusion after removal of swap.
Also, if external definition are redundant and classify to previous design.

Sorry, but which KPIs were degradated after the swap has been finished?
The old antennas were kept and physical pararemeters are as before the swap?
Have you verified the alarms, mainly related with VSWR?
During the swap, any new carrier or modernization were issued?
Have you compared the new covered area? Maybe overshooting cells rised after the swap?

I agree.
@akifpk, did you check the VSWR and the packet loss?

KPI are degraded in 2G and 4G after removing swap.
(Degraded KPIs: 2G mainly Access KPIs, and 4G MIMO RANK and Payload).

All cable tracing has been done no issue also found.

No such alarm rise.

Did you check the propagation?
Is it the same as before?

Also check if it’s converted into a partial swap.

Whenever you change vendors, KPIs have to be revised (i mean pegging points, definitions).
Although names are the same, they don’t always mean the exact same thing.
I’d start with comparing data volumes on Core level.

Its not a swap project site.
Swap occurred between sectors when KPIs are improved.

So, it is not a swap. Right?
You mean maybe a modernization.

Did you check the transmission (IP route, IP Path, etc)?

No packet loss in transmission path.

Considering it is a sector swap, some verifications points can help:

  • Neighbors relations (Is ANR LTE and LTE/2G activated?);
  • CSFallback parameters definiton. Is it OK?
  • Traffic distribtuion.
  • Layers definitions
  • 2G frequenct plan
  • As mentioned here PCI planning
  • Overhooting cells
  • Frequency guard band between 2G/4G if they are using the same frequency band

As mentioned, after removing cable swap KPI degraded, i.e. MIMO RANK and Payload, it’s quite interesting.
Both of them are some how related with radio conditions, which for sure change on site. Maybe someone changed tilt.
Any site come in nearby area? I mean, any small cell integrated nearby?
What is value of CQI before and after removal of swap?

I have had a similar situation with Huawei equipment.
No packet loss, and so on…
But the IP Path was configured the wrong way, affecting directly the QCI 9 and QCI 7, and KPI degraded.

Is the same antenna model and configuration
like EDT, MDT and Azimuth?

Degradation happened on all 3 sectors and all layers? Did you correlate it to traffic/users? Also pls verify PCI design after swap clearance their might be clashes