Detection of external interference while doing drive test on 900 and 1800 LTE band

4G LTE
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1

Can someone pls help with the suggestion on detection of external interference while doing drive test on 900 and 1800 LTE band.

Customer experience is bad.

2

Is it high UL RSSI ?

3

RSSI doesn’t indicate either UL or DL . But the value is -80.81dbm

4

Do you mean interference toward BTS or UE?

5

After Optimization, I was able to achieve RSSI of -70.68

Interference is towards the UE. However, since it’s external interference, I believe it affects the two

6

Only certain area or all over?

7

Yes, in certain areas.

8

Your value seem like UL RSSI to me because that’s the one we always look at . Try to get performance UL RSSI stats

9

How should I get the UL RSSI stats?

10

You can check whether it is always high or only at certain times. High UL RSSI can be on many sectors.

11

Can the UL RSSI stats be detected while drive testing?

12

Something else I can think of is increase of traffic, poor cable installation, and also external device

13

what if it’s the external device?

14

No, UL RSSI can only be collected on BTS side, that means from moshell if its Ericcson
To detect external interference you need a scanner…you might be able to prove there is an external device interference, but to locate where the device is, is very very difficult

15

That value from DT is DL RSSI . -70 dbm is of course better than -80

16

Yes, can BLER show interference?

17

What’s you noise floor? A high noise floor will indicate external interference on the DL (customer side). Download LTE Discovery, Network Cell Info or My Mobile Coverage apps to your Android device and that way you can record the PCIs and the RSRP-RSI and SNR. Thatd give you an Idea where to start looking. If it’s external you need to check if your other sectors are creating it (you can turn them off) or use an Spec A and scan your channels. External interference is one of the hardest things to troubleshoot/find but it’s doable. Hope this helps.

18

I think you have to use scanner as pctel with tems investigation or use spectrum analyser to detect external interference, the best one use spectrum analyser

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19

Do you have CDMA2000 carriers (operators)?
CDMA2000 may cause external interference on EGSM band

20

The LTE bands are 900 and 1800. I don’t think CDMA has its bands