Does very low MIMO issue can impact to on Erab drop rate?

RAN
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1

Hi Experts.

Does very low MIMO issue can impact to on Erab drop rate?

2

If you don’t have rank2,3,4 together more than 50% you have a problem with cabling in LTE.

I do not think MIMO could impact somehow erab drop rate.

3

But KPIs show that Erab drop rate increase with Decrease of MIMO.
(So that way I’m asking)

4

Yes, may be due to CRS port mapping.

First check its Tx /Rx mode, how much dip of MIMO is observed with rise in ERAB DCR?

Secondly what about CSSR and DL retransmission rate?

5

But what did you do that MIMO average rank decreased?

6

I have completed with cable/jumber tracing till port but no such issue found till now.

7

issue could be at the HW connections between radios and antenna or could be antenna by itself. Is field teams check the cabling ? How about RSSI, VSWR? Did u also check the features and parameters set correctly for MIMO? Normal conditions, MIMO relates with throughput…if erab drops are increased , I suspect some issues at the site like cabling, radio, antenna , etc…

8

Any swap in site? Diversity/cyclic?

9

I have checked - no swap found!

10

MIMO decreasing is not the cause for your DCR increasing but both are causeb by another route cause.
Something related to CQI or SNR increasing.
Have you checked if some change was done that increases cells overlapping, for example?
Or problems related to cell downtime.