PUSCH and Uppts interference

Hi Experts,
How do you deal with pusch interference?
And Uppts interference?

I have issue in 1st carrier of TDD only. (It ll also appear in a neighbouring sector)
I have tried interference suppression, pusch irc switch , randomisation via ENB based,
It has had no impact on interference.

Any recommendations?

Have you checked UL BLER? Does it increases as well?
I’m suspecting ducting in your case i.e. external interference source.

Also it may be due to GPS toggling alarm, it will appear in one site and Most of the Neighboring area will be impacted.
Please check GPS alarms and availability.

No alarms on site. (And no GPS alarm).
Swept through.

Then it may due to External interference, May be illegal repeaters, or Ducting.

Have you checked interference on OFDM symbols for special subframe?

Usually is due to strong PRACH interference.
Have you tried to change preamble format, zerocorrelationzoneconfig?

Prach interference is ok.
It’s graph takes the shape of pusch interference

image

You didn’t get my suggestion.
PRACH, due to large delays on cells, is interfering the PUSCH so you will get PUSCH degradation not PRACH degradation.

What prach config index has your cell and what zerocorrelationzoneconfig?
How many intra-freq neighbours have your cell?
In your chart I see values like -120 dBm max for PUSCH.
It is not too bad, I think.

1 Like

Prach config index is NULL.
Zero correlation is 11.

Zero correlation 11 corresponds to a maximum cell range of 12 km.

So if you have users served from 15 km for example than there will PUSCH interference by PRACH.

This is why I asked how many neighbours has your cell to understand how large is the footprint: so you have 30 neighbours, 60 neighbours, 100 neighbours?

The affected sector has 4 neighbours.

Ok, so it is a country side cell probably covering a village or something.
What’s the height and downtilt?

It’s the last site.
Not highly populated area. Down tilt is at 2 currently. It was zero. Height 45m.
But one of the neighbours too has similar problem.
I have 2 tdd carriers in one sector.
Issue only showing up in 1st carrier/ 2nd carrier is ok.
In both cases where I have this issue.
One sector of the neighbour in 1st carrier only for have the same trend shared earlier

When did you change tilt from 0 to 2?

Maybe you should go to 3 downtilt and then you could see improvements in everything.

Few days ago. Due to this issue.

2 degree is not enough, till shooting to the stars. Make it 3 degrees and have a look again
45m height and 2 degree only tilt you get no coverage close to site like this.
Make it 3 degrees and all KPIs will improve and you will get rid of the area with problem (far from site) where anyway UE has not enough power to serve it.

If issue exists in 1st tier neighbours?

Take them one by one. First implement tilt 3 degrees and see how it goes.

Almost vertical beam width of antennas are about 7°.
So if tilt = 2, alot of signal will go to sky.
And it waste.