interference in U900

[almoqbali36]

Do you have CDMA 850 . if yes as vaampeere said you need filter due to intermodulation.

BR

Dear
We don't have

[Feriko]

Hi,

you have to give more information in order to get helped....

- Try to halt / block 2G cells, if RTWP gets down when halted, it's clearly an IM problem. Then you'll have to check the antenna system, every connector, every passive element, to find where the problem source is. Or you can measure the antenna system with a PIM tester if you have the chance to get one.

- If you halt all cells, 2G and 3G, and RTWP is still high, then you're probably having an external interference. I understand that you have already check that seeing yous comments, so please chech first of all the above point and tell us.

Regards,

David

[RF engineer]

Dear
We don't have

Your U900 taking more user or U2100? and for RTWP you are considering average or maximum in KPI when looking to RTWP? as for my network checked when checked the RTWP increase with HS users increase as this is normal .

BR

[brianm]

1. Make sure you did your frequency refarming correctly including on neighbouring sites. Will be better if you can refarm the whole BSC/cluster
2. Do a footprint optimisation on the surrounding 2G sites to limit over-lapping of signals
3. Reduce excess capacity of 2G sites so that your frequency reuse is greatly reduced
4. Swap around the radio's to check if the interference will move from one sector to the other

[Optimustron]

If you have the UMTS BAND above the GSM BAND is a bad thing, you need to switch the bands because if a single connector/cable/antenna/TRX of GSM is bad you will get IM, by the way you always will have IM but the cuestion is that you have a low level for you technology, for example for UMTS you need to have at most only -130 dBc or -87 dBm because if not you will have high RTWP depending on the level, for LTE you need at most -140 dBc or -97 dBm, by the way you can't remove it by means of filtering because it's in your Rx band then you need to kill that from the source.
Another source of interference is if there is a 800 or 850 Mhz system in your country, because this band have 14 Mhz that overlaps the EGSM band, if that is the case you can use filters and you'll need to put frequencies starting from 904 Mhz at least because if not your RX is desensitized and you'll get high RTWP.
If there is a HIGH BRODCAST TX like TV or FM transmiter or maybe a repeater from another band near to your base station you can get high RTWP too and you don´t will see any interference in your band.
Check if there is a structure of metal near to the antennas, or maybe someting like improper type of paint for your antennas or camouflage in order to hide your antennas, then you can get IM from this kind of passive sources.

Excuse me for this rush and little explanation, However I hope this can help you, best regards,

[zeldalcl]

Hi!
U can think about:
1. Does it has any 850Mhz Network, especially CDMA technology are working.
2. May be equiments issued

BRs!

[brianm]

If you have the UMTS BAND above the GSM BAND is a bad thing, you need to switch the bands because if a single connector/cable/antenna/TRX of GSM is bad you will get IM, by the way you always will have IM but the cuestion is that you have a low level for you technology, for example for UMTS you need to have at most only -130 dBc or -87 dBm because if not you will have high RTWP depending on the level, for LTE you need at most -140 dBc or -97 dBm, by the way you can't remove it by means of filtering because it's in your Rx band then you need to kill that from the source.
Another source of interference is if there is a 800 or 850 Mhz system in your country, because this band have 14 Mhz that overlaps the EGSM band, if that is the case you can use filters and you'll need to put frequencies starting from 904 Mhz at least because if not your RX is desensitized and you'll get high RTWP.
If there is a HIGH BRODCAST TX like TV or FM transmiter or maybe a repeater from another band near to your base station you can get high RTWP too and you don´t will see any interference in your band.
Check if there is a structure of metal near to the antennas, or maybe someting like improper type of paint for your antennas or camouflage in order to hide your antennas, then you can get IM from this kind of passive sources.

Excuse me for this rush and little explanation, However I hope this can help you, best regards,

Can you please explain what you mean by "UMTS above the GSM band" and where the switching is done.

Thanks