UL interference occured at combine system WCDMA850 and GSM1800

[Nipon]

Hi,
I have found one problem case in DAS, combine WCDMA850 and GSM1800, by Combiner, there are a high RTWP (in WCDMA850) and high ICM band (GSM1800), suspect that the cause is come from Combiner unit becasue when change to the new one, problem is cleared. But after bring that combiner unit to lab test, it is not failure. isolation, VSWR and PIM test result is normal. So I dont know now what is a real cause...

Anyone suggest me?

[kamy]

Hi,
I have found one problem case in DAS, combine WCDMA850 and GSM1800, by Combiner, there are a high RTWP (in WCDMA850) and high ICM band (GSM1800), suspect that the cause is come from Combiner unit becasue when change to the new one, problem is cleared. But after bring that combiner unit to lab test, it is not failure. isolation, VSWR and PIM test result is normal. So I dont know now what is a real cause...

Anyone suggest me?

you should check for this:
+ congestion interference
+ Spurious interference
+ Intermodulation interference

one of the methods is using spectrum analyzer and directional antennas to detect the interference sources

highly recommended this docs:
W-Indoor Coverage Design Guide-20060817-A-3.1.pdf
from Huawei.

[Nipon]

many thanks Kamy, I am considering to use spectrum tool for test also, but no idea test procedure, should it be BTS offline test or connect to the antenna for test? :confused:

Moreover, may I ask you a W-Indoor Coverage Design Guide-20060817-A-3.1.pdf doc please?

[kamy]

many thanks Kamy, I am considering to use spectrum tool for test also, but no idea test procedure, should it be BTS offline test or connect to the antenna for test? :confused:

Moreover, may I ask you a W-Indoor Coverage Design Guide-20060817-A-3.1.pdf doc please?

BTS should keep online and using scanning test procedure.

[chachajarv]

I think from Lmt tools we can do Rx scanning to make sure its ext / int interference

[danikd]

Hi,
I have found one problem case in DAS, combine WCDMA850 and GSM1800, by Combiner, there are a high RTWP (in WCDMA850) and high ICM band (GSM1800), suspect that the cause is come from Combiner unit becasue when change to the new one, problem is cleared. But after bring that combiner unit to lab test, it is not failure. isolation, VSWR and PIM test result is normal. So I dont know now what is a real cause...

Anyone suggest me?

You have mentioned DAS - Distributed Antenna System.

Can you elaborate on it? What kind of DAS solution did you use for this site?

If it simple passive coax DAS or some active elements used in this DAS like RF to Fiber or RF to CAT5? or similar?