High RTWP level in Huawei UMTS network

[lpkojihu]

Dear colleagues,

We experiencing exceptionally high level for RTWP measurements for many cells in Huawei UMTS network. Such level (-85....-75dBm) can not be explained by regular interference caused by mobile phones. This is a new UMTS network with very low traffic.
Spectrum analyzer measurements did not show any external interference sources. Typically measured RTWP with spectrum analyzer is around -110dBm

Event measurements through UMTS cell antenna shows -110dBm level.

Only when RRU unit is in operation the measured RTWP jumps to -80dBm.

GSM and UMTS networks are fully separated and isolated, i.e. separate antennae used and they are space separated and only single carrier used in UMTS - this excludes any source of Intermodulation cause.

The only problem that I can raise is a problem with RRUs. There are ~30% of cells are suffering from constant high RTWP level and 70% of cell suffering from peak levels of RTWP.

Please, assist with possible solution. Or you may know if some issues with new generation of the Huawei UMTS equipment.

Best regards

[bindi]

If you have already checked with spectrum analyzer and ruled out external interference, then it clearly looks like hardware issues. May be it was a particular batch of faulty hardware (RRU/MHAs etc), or even commissioning file may be. Check settings, in the comm file or if there are any switches needed to be set in node B for this.

[mobilink999]

Are you using TMA ??? whats attenuation setting??

use lst rxatten in MML and share with us.

[aly280779]

Hi,
Have you already checked if there is any cross sector? Because if it is the case you must correct it first. Check also neighboor declaration.

[D33T0X]

Are the RTWP levels constantly high? If yes then you have hardware issue. If the high RTWP levels come and go - that can be external interference.

[mdiazd]

The possible cause is the frequency of GSM carry, This generated intermodulation in you Reception of UMTS. The receiver are superheterodine circuit, and down convertion used a mutilplier, the multiplier generates harmonics that fall in the uplink Umts Carry.

You need set The GSM carry in other frequency, so that the intermodulation is out band the uplink UMTS carry .

[romagdinio]

which RNC software are you using RAN 10? and which SPC?

[sonerss]

Hi

Have you ever change the RRU?? It looks like a Hw problem.. Maybe you can control vswr values each fiders

BR

Dear colleagues,

We experiencing exceptionally high level for RTWP measurements for many cells in Huawei UMTS network. Such level (-85....-75dBm) can not be explained by regular interference caused by mobile phones. This is a new UMTS network with very low traffic.
Spectrum analyzer measurements did not show any external interference sources. Typically measured RTWP with spectrum analyzer is around -110dBm

Event measurements through UMTS cell antenna shows -110dBm level.

Only when RRU unit is in operation the measured RTWP jumps to -80dBm.

GSM and UMTS networks are fully separated and isolated, i.e. separate antennae used and they are space separated and only single carrier used in UMTS - this excludes any source of Intermodulation cause.

The only problem that I can raise is a problem with RRUs. There are ~30% of cells are suffering from constant high RTWP level and 70% of cell suffering from peak levels of RTWP.

Please, assist with possible solution. Or you may know if some issues with new generation of the Huawei UMTS equipment.

Best regards

[patek1968]

RTWP is caused by faulty hardware or loosed cables that weren't properly terminated..if its HW you can check in m2000 for the RTWP value and therefore can address this to their PM..

[danikd]

We have a similar problem in our Huawei network....we could not not find any external interference. The high RTWP appears only when RRU connected to the antenna. RRU replacement did not solve the problem, even UL frequency change did not show improvement.
Any thoughts about RRU performance? Any trouble tickets open?
Huawei told us just install filters, but I do not understand how it can solve a problem, since nothing appears on UL channel in the air.

Dear colleagues,

We experiencing exceptionally high level for RTWP measurements for many cells in Huawei UMTS network. Such level (-85....-75dBm) can not be explained by regular interference caused by mobile phones. This is a new UMTS network with very low traffic.
Spectrum analyzer measurements did not show any external interference sources. Typically measured RTWP with spectrum analyzer is around -110dBm

Event measurements through UMTS cell antenna shows -110dBm level.

Only when RRU unit is in operation the measured RTWP jumps to -80dBm.

GSM and UMTS networks are fully separated and isolated, i.e. separate antennae used and they are space separated and only single carrier used in UMTS - this excludes any source of Intermodulation cause.

The only problem that I can raise is a problem with RRUs. There are ~30% of cells are suffering from constant high RTWP level and 70% of cell suffering from peak levels of RTWP.

Please, assist with possible solution. Or you may know if some issues with new generation of the Huawei UMTS equipment.

Best regards