Solution fo UL very high and DL very low, RSRP very nice and SINR very poor

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21

Serving Cell RSRQ (dB):

image

CQI CW 0 Carrier 1:
image

22

Check this, RSRP in server cell and Neigh 1 are the same:

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image785×558 118 KB

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image785×558 139 KB

23

Hmm…this sounds like MIMO cabling problem.
Like on one sector you have TX cables from 2 different sectors.
Check MIMO counters to clarify this.

24

You say that in one antenna you have TX cable of sector 1 or 2 for example?

25

Yes, maybe.

26

What Counter do I need to check, please?

27

What’s the site MIMO config 2x2 or 4x4?
Average and max rank indicator.
If MIMO cables are twisted then rank should always be 1 meaning only 1 layer for MIMO spatial multiplexing.

28

It’s MIMO 2x2.

29

Then rank should be always 1 in counters for 2 sectors, not just for one sector.
If you never see samples of 2 layers for mimo then this is it: MIMO cables twisted on site between sectors
Please check counters from several days plotted by hours and see rank indicator or number of layers.
If both are 1 then MIMO cables are twisted.

30

RI Carrier 1:
image

31

So it is always 1 in Drive Test.
This is a good hint I am right.
But check counters for Rank Indicator and MIMO layers.
For cells, in OSS.

1 Like
32

Couldn’t it cause high VSWR?

33

No I don’t think so.
It’s just that different signals are radiated on a wrong antenna.
That’s all.

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34

So cross feeder alarm?

35

Nope. No such alarms. Paths are orthogonal +45 and -45 degrees.

Or maybe there is?
Which vendor is it?
Was site like this since integration or it just happens recently?

36

Vendor is ZTE.
Issue only happening recently.
Site have 3 years in service, and no recent intervention on site recently.

37

Yes, we need to plot counters of rank and mimo layers to conclude.

It may not be MIMO issue but 2 PCIs having same signal strength coming from pretty much same direction.
So again too much overlapping between cells.
It is weird that 2 PCIs have exactly same RSRP as in your picture.

1 Like
38

I think that there are bad connections, because RTWP in sector B don’t measure, and in Sector C have one in -104.
Average RSSI Charts…

Average RSSI Sector A:

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Average RSSI Sector B:

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image697×431 65.4 KB

Average RSSI Sector C:

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image829×421 77.7 KB

39

Usually policy got wrongly implemented at router end then such cases apear.

40

This is another problem you have to fix as a flat RTWP.